While short may be handy if all you want is numbered instruction on how to fix an item, I much prefer the long in real time compete with back story and chat. You learn more and can actually fix stuff live along side without constantly pausing which even on short you need to do. Best of all you get occasional insights into the Sony pro repair days, production company detail and weather/nature content which adds extra interest especially when watched from another country. Either way great videos which give confidence and instruction to many. I bet i’m not the only one who thanks to you have re-purchased old Hifi video and dvd tech I used to own in the late 80’s and successfully repair it /enjoy again 💯✅👍😊
Keep the old way if you don’t like something ff is a wonderful tool to skip ahead. You are old school repair tech please keep us in the loop of the whole process. Thanks Dave
FF is wonderful but doing so much is missed and then i have to field questions that were covered but missed because people skipped and they get all bent out of shape when i call them out on not paying attention.
X gen tech here. (born in 88). This is another reason I do not trust fluorescent displays. I would have modified the display for LED readout. Taken far longer, but more reliable. Thank you for keeping these going.
i like all your videos and enjoy your chat and your problem solving for me. i feel it is important to involve what techniques you apply and why. Great work.
Very interesting watch ,And it shows one needs experienced knowledge as well and how one can be fooled by using a ESR meter that didn't cut the mustard , Always enjoy ur video's many thanks again for sharing.
Bit unfair....what would you expect an ESR meter to read with a shorted cap? It gave the right reading. You just need to be aware of the other possibilities.
just as an example of why i like your longer videos i found myself trying to work out your technique of converting 12vlts to 9 volts for the casette motor replacement recently. I think i got it but maybe you could explain more. Great work
Dave, I generally watch most anything repair related that you post! Thank you so much for everything you do! I prefer the longer videos, they give more context and it is easy enough to skip through the portions that I'm not interested in. I'd personally prefer to see you use your time creating new repair videos rather than going back and editing down old videos. Like a good movie, this is part of the adventure with the twists and turns. I like the VCR repair videos the best. Have you ever considered doing something like "repair clinic" videos where you help someone out in the field remotely through their repair? You get the video of the person doing the repair and the person gets your expert help. I'd gladly submit high quality videos to you to help me repair something.
I enjoy some of your stories. I like the repairs you do on the old high power receivers. I just wished they still made replacement parts for some of them.
I got the tuner (in dark brown) cheaply from a dealer in Hamburg in 1984 as an exhibition piece because the F socket was virtually unknown in Europe and no one wanted to buy it. The standard only came to Europe through satellite reception. Unfortunately, the gold caps expired while they were still able to store the channels, which was a problem for the PCB.
I think these shorter versions are great because they go straight to the point. Although, I still like the longer videos because often times you share various stories and anecdotes, and there's more time to follow your thought processes and how exactly you find the fault. So I'd say that I don't mind these short versions of older videos, but definitely don't forgo making longer and more in depth videos that you've been doing
I watch your videos everyday and sometimes a brief version is better. I will add that the 30 min ones I do occasionally skip through them for the result, but not often.
How many volts was on the -31.8V VKK line with the bad capacitor? I'm asking because I have an LG micro hifi with a dim display, it's VKK line is -27V and it is okay, so where could be the issue?
It's nice to see reuploads of older vids from the point of view that I've not dug down far enough to have seen them yet, but if I'm honest I'd still prefer the chat & diagnoses left in. Perhaps as a happy medium you could link the original video in a pinned comment for those of us who'd like to see the originals? Cheers
I have an RTL SDR dongle and use it to listen to radio signals. It has a similar bandwidth adjustment and for weaker FM stations I lower the bandwidth and the station comes in a little clearer. Also there are only two FM stations in my area that have the two digital sidebars along the analog signal.
Great vid! I always measure voltage across each cap in a voltage multiplier. Find one that doesn't have the voltage across it that should be there for that stage you have a shorted capacitor.
In a voltage multiplier all the capacitors in series with the AC will eventually fail as they continually have both foils eroded and reformed. The ones with the diodes across last well, as the 0.6V reverse bias is not enough to degrade the oxide film.
Good call! Most people think that it's the tube that is dying but I suspect that people have forgotten how reliable vacuum tubes were. Just like transistors, they don't die for no reason! There's always another culprit...
Hello, some parts of colored displays (at 3:18), really, they are colored or they are colored filters. P.S.: Any tips on a simple circuit to generate negative power (-24 to -30v) for the VFD Anodes? Thanks.
I have had this same problem with a lot of Akai vcrs in the day. A lot of those models used the same circuit for the display. Replacing all 4 caps was a standard fix for the "dim display" and was a common fault. I think what goes wrong is the frequency of the inverter is very high and causes heat in the cap and a premature failure of the cap . The same thing happens with switch mode power supplies and the filter caps on the output rails. Good video though .
Replacing all 4 is the lazy way. Finding the fault is the final part. They won't all fail. Used to see it all the time on VCRs. Just swap the bad one and the unit never came back. Never did all because the shop charged 4.00 per cap for parts. Changing one got me in under the call if over limit. Changing all 4 would put me over the limit and i would have to call with an estimate and there was a 50/50 chance they would say no and then I got nothing. We didn't charge an estimate fee so it was important to get in under that limit of 75.00 for the repair. 70 labour plus 4 in parts. Believe you me I had many times where I had 2 or 3 parts and the estimate came in 76 or 79 and the customer said no. Then i had to remove the parts and give it back free. Got burned a few times.
@@12voltvids yes agree, problem is just replacing the faulty cap the others would also be on the way out. How long before the others also fail is anyone's guess. That's when you would phone the customer and put it to them and let them make that decision to go the extra mile. That way if the repair bounces, you are covered. $4.00 for a cap is up there, but what service centers have to charge to make money and stay in business. I used to charge similar prices, eg a T205 fuse was $2.00. Labour was then $85.00 HR and this was in 2012 when I left the service industry then. I now drive coaches for a living and clear ( after tax ) $1900 for a 35 HR week. I some times miss the bench work, but not the stress. But I did injoy the chase of tracking down a tricky fault.
@@stephengorin3059 not necessarily. This repair was done 5 years ago and I know the tuner and it runs daily several hours a day. I got out of the service business in 2003, moved on to phone company. 37.5 hour week, pension 4 day work week.
Greetings! I have a Technics SA-CH455 that I picked up at Goodwill. Everything seems to work, but the display of the tuner/cassette deck is barely visible. I cannot seem to find a decent schematic for the 455. Any ideas on what and/or where I should be looking for a fix? Thanks!
I've seen that same defect before... usually the caps go out or the display is EOL. BTW , buy a componenttester. It tells you right away that the capacity is off-spec. Usually I exchange caps that are more than 10% off.
I had a Sony CD player that the screen took a minute to turn on, I originally thought it was just weak or maybe bad caps, but it turned out there was corrosion that ate away the trace for the heater. Apparently, the display eventually got hot enough just from both heat from the machine, and heat from the plate in the display that it would dimly show things after a while
Looking for a tech to repair my sansui s-x1130's VFD in the Oregon area and it strikes me that most tech's won't be versted in the VFD's. Were are you located and do you do repairs for clients still? Thanks Matt
Did you ever do rejuvenation of a VFD display? Would be interested in your thoughts on that. But this video is a nice reminder there is other things to check first. 🙂
Thanks Dave, i have 2 Technics ST-S7 tuners black and silver that match my two Technics SU-V8 amplifiers. I changed the caps to new (nichicon pws), but both displays are dim. I have to work out what you mean by bridging , as maybe it needs more power to the display.
Can you make a video on how to desolder without damage to the board? I've been practicing removing ICs from scrap boards, I learned how to get the chips out OK (with help from a hot air station) but sometimes I think I'm ripping the solder pads on the board on some pins. I think I can desolder things like capacitors and resistors easily since those only have two legs. Are solder suckers good to use or should you use desoldering wick? I have two friends, one says the sucker rips the pads and another friend who says the wick is terrible. Thought it would be interesting to hear your input.
Hello again Dave. I've toured your very informative VFD related vids again as I have been given an old Teac AG-790 that has a dim VFD. The voltages check out (-32V at the 'plate', 4Vac across the filaments, and 5.1V bias supplied by a zener connected to the filaments transfomer's centre-tap). Then I came across your Biasing Your Vacuum Tube Amp video; very interesting, not just for VFD info, but I worked on valve stuff when I was a kid. Anyway, since a VFD is a valve of sorts, what's wrong with altering the VFD bias in the same way as you recommend setting up ageing valves? What are your thoughts on reducing the bias by replacing the 5.1V zener with a lower value, (since the 'HT' is negative), obviously taking into account the current limiting resistor? At best the display will be a bit brighter but uneven. At worst I'm on my way to the burns unit again. Regards.
@@12voltvids Thanks for getting back to me Dave. I think I'll get a selection of zeners and give them a try anyway. Also, there are bits of info elsewhere on the internet that discuss rejuvenating VFDs by increasing the plate voltage (temporarily), and raising the filament voltage a bit. I'll do a bit of tinkering. If I have any luck, I'll let you know. One annoying observation, is that when I take the front panel cover off, the VFD is pretty bright. But, the front panel cover includes a colour filter to mask the VFD electrodes, but it attenuates the VFD light a fair bit. It's a pity the designers could not have included a feature to adjust the display brightness, or peel-off filters behind the front panel. Regards.
I've know Paul for years and yet I can't remember the last time I saw one of his videos. But then again I don't follow many TH-cam channels and the ones i do are not about electronics. Planes trains and automobiles. That's what i watch, that and the jazz music channels.
Dave, I like that short is quick and to the point. Long sometimes has some juicy nuggets of information. Your choice. Question: Are all fluorescent displays powered this way? Thanks a lot, Tom
Yes the 20 min version is great. When you are editing your earlier vids...you should do a blooper reel of the times you snapped. Those were some of the best parts of the earlier vids.
I have a GE Sapcesaveer microwave with a VFD. The left side is pretty good, and the right is very dim. I don't have a schematic. I suppose I need to get in there and compare voltages, then guess which parts to pull and test.
Great video as usual. I own a Panasonic saak 29 shelf stereo that sounds great but the display is very dim and the tech I took it to said that the fossils itself was bad but was wondering if you might have a different opinion on the matter? Thanks a lot!
I like the longer videos, i've learnt a lot watching them especially the ones that take you a while to find the problem, it's given me a few tip's for what to look for with cassette decks, I started buying them and repairing them after a neighbour gave me a 1978 pioneer ct-200, i've now got 17 and 14 working, any tips how to replace the sensor bulbs on sony tc-v7's would be much appreciated
I agree, the longer videos are my favourite. I like your rationals, explanations of your approach, and detailed thoughts you had to resolving the problem. I also like seeing your testing tools, and your diagnostics. So I vote to keep things the same. Thanks for making it look easy, even when it’s not. Also like it when you talk about your parts, substitutions when original not available etc.
@@12voltvids Ignore the people who say they want shorter videos. Your true fans want the long in-depth videos. Anyone who wants shorter videos isn't interested in actually repairing electronics.
@@petenamlook18 I hear you. Short videos are not coming any time soon, but shortened versions of older videos may show up with irrelevant material removed from time to time.
Yes they fade with age. Some faster than others. I have a clock that the vfd failed. I changed it for another one i pulled from another clock module that i had used the chip to make a jumbo display clock.
@@12voltvids Unfortunately I can't do the same thing with my AKAI DT200 timer. They're rare to find and would cost just as much to get! I was secretly hoping you had a magic solution for reviving VFDs!
@@Stelios.Posantzis you can raise the filament voltage slightly. That will heat the hot cathode and create more emission but this is a temporary fix. Most last a long time. I have some displays over 40 years old still relatively bright. It depends on the tube. I built a 6 digit VFD clock a couple of years ago. Perhaps 3 (the build is on my channel) and the 10 minute tube is so dim it barely shows now. Depends on how well the tube was made. Good tubes last a long long long time. The original one from my 1979 RCA VCR is still good . When i scrapped the VCR i made a clock out of it. Still works and it is 42 years old and bright as anything.
Some of the older ones are too long and will be redone at some point. I will be editing off the source files, so it wont just be a shortened video, and most of the audio will be dubbed in to explain what I am doing as I did in this one.
@@12voltvids That's fine, perfect. What stops me looking through some of the older stuff is they are just to long. I just want to see the fault, finding it, fixing it and seeing it work (but not a long working bit) and that is it. It will also allow other to look through some of the older ones, plus, you will get adverts twice for one video :-))
@@12voltvids let's not forget DC leakage current test! Which is what that capacitor you replaced was suffering from! And there's no other way around it, they have to be removed to be tested! They usually show up as having good ESR which throw's of a lot of people as not many people seem to know about that failure mode and therefore don't have the means to test for it...
@@PeterMilanovski No this one shorted. Not leakage. Leakage was really only an issue in the wax coupling caps in tube gear. Electrolytics generally do not go DC leaky unless they short completely as this one did.
@@12voltvids actually you might be surprised, modern electrolytic capacitors are also leaky, the one that you pulled out was really bad! I can't remember if you had one of those cheap Chinese multi component testers, those things usually give a Vloss reading when testing capacitors, this is a great test feature that the majority of people who have one don't even look at the percentage of Vloss because they don't know what it's for or what it means... The old wax paper capacitors do leak... But you have to remember that those things were way underated! You can easily put twice the rated voltage across it when new and it will be fine, try that with a modern electrolytic capacitor LoL... It's also the reason why the wax paper capacitors lasted so long! If you do the same for your own equipment, replace capacitors with twice the rated voltage or higher if the size allowed, your equipment will last a lifetime! I have tried various methods for testing capacitor leakage current, from an LCR Bridge Meter to a simple Lab Power Supply with a uA analogue meter showing up the leakage current.. Sure! You might say that a few uA of leakage current is nothing, well... I can tell you about an article that I read in Electronics Australia, I believe that it was from the 60's, manufacturers were trying to move away from using a traditional transformer in the power supply of TV's in order to cut costs. The new TV's were going to use a half wave rectifier as the power supply, the only problem with this was that the Melbourne board of works tested this as the galvanized pipes used back then were actually the neutral to the electrical system in the house. This new style of TV was sending mA of DC current on top of the AC which caused a brand new galvanized pipe in the ground to rot within a week! Due to electrolysis. There had been a few of these new TV's sold in the country but it wasn't long before they were banned from the Australia, the government bought back the ones that had already sold, it was also found that the small DC leakage current was causing the transformer on the power poles to overheat! Hence the reason why a vacuum tube amplifier has huge output transformers! You essentially have both DC and the AC ripple which is the music that's going to make it across to the secondary side, if you can figure out how to get the DC off the output transformer, which has been done, you can get away with much smaller transformers, so basically.... The less that a capacitor leaks DC current, the better! But first you have to be aware of this particular problem and then have the equipment to identify it... You can probably tell that I have spent far to much time on the topic of capacitor failure... I used to use an ESR years ago and while it seemed to work great, every now and again I would run into a piece of equipment that should for all intents and purposes work properly but doesn't! This drove me nuts! So I went on a research bender and found that a leaky capacitor is worse than a capacitor with high ESR! Now! I always check them on an LCR Bridge Meter, the one that I use shows all the details on the one screen! So with one glance, I know exactly what condition it is in.. and I have never had a problem since! When it comes to equipment from a customer! It's always up to them for what they want to achieve... But I always give them the opportunity to choose... You would be surprised how many people would choose to spend more money when they realise that if their equipment is done properly, it's cheaper than replacing it with something new that will most likely be more difficult to repair... The old one lasted 30 years, the new one will not! And I have never advertised! It's all word of mouth... You have an amazing skill, your ability to fault find is second to none! But you have to keep an eye on capacitor DC leakage current... It's a real silent killer... Let alone electrolyte leakage and expansion, high ESR and all that... It would be so much easier if we didn't need them but we haven't found a good replacement... All we can do is keep those soldering irons on standby LoL.
@@PeterMilanovski On low voltage low impedience circuits this just isn'r an issue like it was on vacuum tube gear. The problem with paper caps was the paper. As it aged acid in the paper from the time it was manufactured gradually turns the capacitor into a resistor. With a high impedance high gain tube circuit it only takes a few microvolts to tickle the grid of the next stage and cause a high dc plate current. This will reduce the life of the tube, and in extreme cases burn out transformers. Solid state circuits this is not nearly as big an issue. Hot chassis leakage is a totally different issue. We had the same problem here, but it was due to submarine DC power cables. Was eating underground pipes. The power company has installed negative electrodes into the ground to mitigate this problem. Firthermore they used ground return. So just the positive wires were sent from the mainland to the island. The negative retudn was a series of electrodes at the shoreline which then went Ariel back to the substation where the rectifiers were. Not all the currents went to these electrodes, so additional kathode electrodes that were fed with about -48v were installed to prevent pipe degradation. Where I live, if you drive 2 ground rods into the ground seperated by about 30 feet, you will have a small differential voltage between them, and can actually pull several amps. All ground electrodes need to be bonded together. This is actually done every 300 metres on all the poles. The multi ground neutral is bonded on every pole that has a transformer and every 300 meters.
Hi sir, I've a Sony MHC- W550 mini hifi home audio system, I'm facing same problem with it's display. The display is too dim, plz give some solution, thank you 🙏
@@12voltvidsAll is not necessarily lost though. This video and all the tips you gave were much appreciated. I have an old Yamaha RX-V390 receiver with a dim display, but all the voltages checked out, and I was resigned to the fact that the age of the VFD was the root cause. However, during reassembly, I noticed that there was a strip of orange film covering the VFD. I peeled it off, expecting the VFD to be brighter but with all the electrodes visible. Not at all. I assume that the designer did not like the blue green colour for some reason, set the VFD circuitry to max brightness, and then put an orange filter on the front of the display. I accept that this may only give me a few more years use, but I'm happy with that.
@@davidwhite9751 must of been one of these blue light snowflakes. Sorry but when someone tells me to put a blue filter on my phone because it is bothering them at the next table I am more likely than not to tell them to eff off. Yes that happened to me once. sitting in a restaurant by myself waiting for my food to come I was surfing around on my phone like a lot of people do. Women sitting at the next table with some little kids has one if the kids whisper something to her then she gets up walks over to my table and asked me to turn down my screen brightness or turn on my blue filter as it was bothering her kids eyes. Guess what i did so apease her. Yup started surfing the twitter feed milfs, juicy mins ect making sure to hold my phone up high enough for them to all get a show. Some people. They should just mind their own business. Bothering little Johnny's eyes. Give me a break. Perhaps if he was sitting in his seat instead of standing on the bench looking over my shoulder at my phone this wouldn't have been ab issue!
Just finished watching the longer version after this short one and I think that I prefer the longer one! It might be a good idea to create a second channel that contains all the short versions, some people like them short and others who need to make a similar repair need the long version! I noticed in the long version, you tested a 100uf capacitor and got a reading of 105uf... A good capacitor should always read right on the mark or just below it! If it's reading above, it's leaking DC current! ie a short or close enough to a short! The ESR meter is only looking for high ESR and nothing more! A shorting capacitor will always return a higher value due to the short appearing to charge longer than it would if it was not shorting... They have to be pulled from circuit to be tested, there's unfortunately no easy way around it! You can quickly go over all capacitors in circuit with the ESR meter but that doesn't tell you everything! As soon as you called out 105uf for a 100uf capacitor, I knew straight away that it's a leaker! There's no such thing as an over achiever when it comes to capacitors!
Go back to school. Capacitors can be 10% under and 20% over. That is the tolerance on electrolytic. So a 100 can measure between 90 and 120 right out of the box.
Starting another channel is not an option because I would have to meet the eligibility requirements to monetize the videos. The new edits of old videos are for those that complain like spoiled brats about videos being too long. For every person that says they like the long version 20 say they like the short version better so you are in the minority.
@@12voltvids I have never measured a new capacitor that was over its rated capacity, only old used capacitors that show low parallel resistance.. but to see that in the first place, first you need the right tools, you can't use a multimeter! It's not sensitive enough! If a multimeter can see it, that cap is bad... Either you have a Heathkit or Eiko leakage tester, or Paul Carlson's capacitor tester which tests for leakage or an LCR Bridge Meter... Some of those Chinese multi component testers will give you a Vloss % reading, it's better than nothing and can identify parallel resistance much better than a multimeter... You call it shorted, this is exactly what low parallel resistance is! It can be so low that a multimeter trying to measure resistance isn't going to be able to do it and just gives you a short reading... I'm sure that you have one of those multi component testers, it's possible that it shows the Vloss reading when testing capacitors but you probably have never taken notice it, it's telling you at what percentage it's shorted, compare some old capacitors that you might have laying around to the same thing in new one's... Actually, make it a video! I don't know what it is but people love watching bad capacitors being treated and compared to new! I would definitely watch that....
@@12voltvids well you are the creator! Kinda like a god LoL, it's your channel at the end of the day and you should do whatever you wanted to achieve! The people who like the short video just want to see the fix, they are not interested in who you are. For those who like the longer video, I think that they are the loyal viewer, they enjoy the fix and anything else that you have to say...
@@PeterMilanovski and there are both versions. The new short versions are remakes of older videos and the old ones are not going away so don't worry, because there will be longer videos still made.
I'm shocked that the esr tester was telling lies or omitting d.c resistance/leakage. That has to be rare, that tester has worked really well for many years. I've never found any fault with your videos. Years ago i tryed to watch mr carlsons channel, Way way too much waffle about nothing.
ESR and low ohms. They measure with Ac at about 100khz. A good cap will look like a short to an ear meyer. That's why you have to test with both dmm and esr or you could miss something.
Of course you can. ESR going up is the first sign that a cap is starting to fail. The only time an esr meter won't work is in the event of the capacitor shorting internally and in all my years of servicing i can tell you i have more fingers than the number of times I have see a cap dead short. In 10 years i have seen it twice. One was the main filter on a power supply.
While short may be handy if all you want is numbered instruction on how to fix an item, I much prefer the long in real time compete with back story and chat. You learn more and can actually fix stuff live along side without constantly pausing which even on short you need to do. Best of all you get occasional insights into the Sony pro repair days, production company detail and weather/nature content which adds extra interest especially when watched from another country. Either way great videos which give confidence and instruction to many. I bet i’m not the only one who thanks to you have re-purchased old Hifi video and dvd tech I used to own in the late 80’s and successfully repair it /enjoy again 💯✅👍😊
Keep the old way if you don’t like something ff is a wonderful tool to skip ahead. You are old school repair tech please keep us in the loop of the whole process. Thanks Dave
FF is wonderful but doing so much is missed and then i have to field questions that were covered but missed because people skipped and they get all bent out of shape when i call them out on not paying attention.
X gen tech here. (born in 88).
This is another reason I do not trust fluorescent displays.
I would have modified the display for LED readout.
Taken far longer, but more reliable.
Thank you for keeping these going.
I’m very happy to see all of your videos in any format thank you for all your hard work
I like the short and to-the-point feel of this video, and I like your other videos where you give some electrical tips to troubleshooting
i like all your videos and enjoy your chat and your problem solving for me. i feel it is important to involve what techniques you apply and why. Great work.
Very interesting watch ,And it shows one needs experienced knowledge as well and how one can be fooled by using a ESR meter that didn't cut the mustard , Always enjoy ur video's many thanks again for sharing.
Bit unfair....what would you expect an ESR meter to read with a shorted cap? It gave the right reading. You just need to be aware of the other possibilities.
just as an example of why i like your longer videos i found myself trying to work out your technique of converting 12vlts to 9 volts for the casette motor replacement recently. I think i got it but maybe you could explain more. Great work
Dave, I generally watch most anything repair related that you post! Thank you so much for everything you do! I prefer the longer videos, they give more context and it is easy enough to skip through the portions that I'm not interested in. I'd personally prefer to see you use your time creating new repair videos rather than going back and editing down old videos. Like a good movie, this is part of the adventure with the twists and turns.
I like the VCR repair videos the best. Have you ever considered doing something like "repair clinic" videos where you help someone out in the field remotely through their repair? You get the video of the person doing the repair and the person gets your expert help. I'd gladly submit high quality videos to you to help me repair something.
Nice tuner I always like the look of Technics components
I enjoy some of your stories. I like the repairs you do on the old high power receivers. I just wished they still made replacement parts for some of them.
Yes!
I like the details you provide so I vote to keep them longer if the info is pertinent.
That's so cool. Great analysis!
I like your little stories but this works as well to sort a problem out quickly.
I got the tuner (in dark brown) cheaply from a dealer in Hamburg in 1984 as an exhibition piece because the F socket was virtually unknown in Europe and no one wanted to buy it. The standard only came to Europe through satellite reception. Unfortunately, the gold caps expired while they were still able to store the channels, which was a problem for the PCB.
I think these shorter versions are great because they go straight to the point. Although, I still like the longer videos because often times you share various stories and anecdotes, and there's more time to follow your thought processes and how exactly you find the fault.
So I'd say that I don't mind these short versions of older videos, but definitely don't forgo making longer and more in depth videos that you've been doing
I watch your videos everyday and sometimes a brief version is better. I will add that the 30 min ones I do occasionally skip through them for the result, but not often.
Great vid Dave, I wish I had your knowledge.
Love the new remix style!
How many volts was on the -31.8V VKK line with the bad capacitor?
I'm asking because I have an LG micro hifi with a dim display, it's VKK line is -27V and it is okay, so where could be the issue?
I personally like the side stories....maybe do another channel called "12volt Quick fixes" with shorter content?
It's nice to see reuploads of older vids from the point of view that I've not dug down far enough to have seen them yet, but if I'm honest I'd still prefer the chat & diagnoses left in. Perhaps as a happy medium you could link the original video in a pinned comment for those of us who'd like to see the originals?
Cheers
I may do just that. Make the original unlisted and then link the original to the short version.
I have an RTL SDR dongle and use it to listen to radio signals. It has a similar bandwidth adjustment and for weaker FM stations I lower the bandwidth and the station comes in a little clearer. Also there are only two FM stations in my area that have the two digital sidebars along the analog signal.
Great vid! I always measure voltage across each cap in a voltage multiplier. Find one that doesn't have the voltage across it that should be there for that stage you have a shorted capacitor.
In a voltage multiplier all the capacitors in series with the AC will eventually fail as they continually have both foils eroded and reformed. The ones with the diodes across last well, as the 0.6V reverse bias is not enough to degrade the oxide film.
@@SeanBZA Exactly. That is why I just measure the voltage across them in the energized circuit, right away. You find the shorts very quickly.
Good call! Most people think that it's the tube that is dying but I suspect that people have forgotten how reliable vacuum tubes were. Just like transistors, they don't die for no reason! There's always another culprit...
Hello, some parts of colored displays (at 3:18), really, they are colored or they are colored filters.
P.S.: Any tips on a simple circuit to generate negative power (-24 to -30v) for the VFD Anodes? Thanks.
I have had this same problem with a lot of Akai vcrs in the day. A lot of those models used the same circuit for the display. Replacing all 4 caps was a standard fix for the "dim display" and was a common fault. I think what goes wrong is the frequency of the inverter is very high and causes heat in the cap and a premature failure of the cap . The same thing happens with switch mode power supplies and the filter caps on the output rails. Good video though .
Replacing all 4 is the lazy way. Finding the fault is the final part. They won't all fail. Used to see it all the time on VCRs. Just swap the bad one and the unit never came back. Never did all because the shop charged 4.00 per cap for parts. Changing one got me in under the call if over limit. Changing all 4 would put me over the limit and i would have to call with an estimate and there was a 50/50 chance they would say no and then I got nothing. We didn't charge an estimate fee so it was important to get in under that limit of 75.00 for the repair. 70 labour plus 4 in parts. Believe you me I had many times where I had 2 or 3 parts and the estimate came in 76 or 79 and the customer said no. Then i had to remove the parts and give it back free. Got burned a few times.
@@12voltvids yes agree, problem is just replacing the faulty cap the others would also be on the way out. How long before the others also fail is anyone's guess. That's when you would phone the customer and put it to them and let them make that decision to go the extra mile. That way if the repair bounces, you are covered. $4.00 for a cap is up there, but what service centers have to charge to make money and stay in business. I used to charge similar prices, eg a T205 fuse was $2.00. Labour was then $85.00 HR and this was in 2012 when I left the service industry then. I now drive coaches for a living and clear ( after tax ) $1900 for a 35 HR week. I some times miss the bench work, but not the stress. But I did injoy the chase of tracking down a tricky fault.
@@stephengorin3059 not necessarily. This repair was done 5 years ago and I know the tuner and it runs daily several hours a day. I got out of the service business in 2003, moved on to phone company. 37.5 hour week, pension 4 day work week.
The length of this one was.fine. Checking your self with other tools, give us an idea of other ways to go.
Greetings! I have a Technics SA-CH455 that I picked up at Goodwill. Everything seems to work, but the display of the tuner/cassette deck is barely visible. I cannot seem to find a decent schematic for the 455. Any ideas on what and/or where I should be looking for a fix? Thanks!
I've seen that same defect before... usually the caps go out or the display is EOL.
BTW , buy a componenttester. It tells you right away that the capacity is off-spec. Usually I exchange caps that are more than 10% off.
The classic doubler or tripper charges the capacitors in parallel then discharges them in series.
do those vacuum displays need as much power as a plasma display?
I had a Sony CD player that the screen took a minute to turn on, I originally thought it was just weak or maybe bad caps, but it turned out there was corrosion that ate away the trace for the heater. Apparently, the display eventually got hot enough just from both heat from the machine, and heat from the plate in the display that it would dimly show things after a while
Did you bodge the trace, yourself?
@@MrChrisRP yep, I used some enamel wire to bridge it
@@joshm264 Cool, good job!
Looking for a tech to repair my sansui s-x1130's VFD in the Oregon area and it strikes me that most tech's won't be versted in the VFD's. Were are you located and do you do repairs for clients still?
Thanks Matt
Did you ever do rejuvenation of a VFD display? Would be interested in your thoughts on that.
But this video is a nice reminder there is other things to check first. 🙂
Thanks Dave, i have 2 Technics ST-S7 tuners black and silver that match my two Technics SU-V8 amplifiers. I changed the caps to new (nichicon pws), but both displays are dim. I have to work out what you mean by bridging , as maybe it needs more power to the display.
I like your videos with all the content if there some people that don't like it maybe they should switch to another provider.
(04:49) That's why I always test caps with a DMM, or a Huntron first, before testing for capacitance, or ESR.
Can you make a video on how to desolder without damage to the board? I've been practicing removing ICs from scrap boards, I learned how to get the chips out OK (with help from a hot air station) but sometimes I think I'm ripping the solder pads on the board on some pins. I think I can desolder things like capacitors and resistors easily since those only have two legs. Are solder suckers good to use or should you use desoldering wick? I have two friends, one says the sucker rips the pads and another friend who says the wick is terrible. Thought it would be interesting to hear your input.
Hello again Dave. I've toured your very informative VFD related vids again as I have been given an old Teac AG-790 that has a dim VFD. The voltages check out (-32V at the 'plate', 4Vac across the filaments, and 5.1V bias supplied by a zener connected to the filaments transfomer's centre-tap). Then I came across your Biasing Your Vacuum Tube Amp video; very interesting, not just for VFD info, but I worked on valve stuff when I was a kid. Anyway, since a VFD is a valve of sorts, what's wrong with altering the VFD bias in the same way as you recommend setting up ageing valves? What are your thoughts on reducing the bias by replacing the 5.1V zener with a lower value, (since the 'HT' is negative), obviously taking into account the current limiting resistor? At best the display will be a bit brighter but uneven. At worst I'm on my way to the burns unit again. Regards.
Vfd fail for many reasons. Phosphor burns, loss of vacuum and filament loses the coating that emits electrons.
@@12voltvids Thanks for getting back to me Dave. I think I'll get a selection of zeners and give them a try anyway. Also, there are bits of info elsewhere on the internet that discuss rejuvenating VFDs by increasing the plate voltage (temporarily), and raising the filament voltage a bit. I'll do a bit of tinkering. If I have any luck, I'll let you know. One annoying observation, is that when I take the front panel cover off, the VFD is pretty bright. But, the front panel cover includes a colour filter to mask the VFD electrodes, but it attenuates the VFD light a fair bit. It's a pity the designers could not have included a feature to adjust the display brightness, or peel-off filters behind the front panel. Regards.
Sounds a good idea but I do like the chatter, especially when it is teaching me something. Also funny stories of crazy things you have seen :D
I prefer the longer versions!
2:30 I can see Mr. Carlson peeking in the corner. :D
I've know Paul for years and yet I can't remember the last time I saw one of his videos. But then again I don't follow many TH-cam channels and the ones i do are not about electronics. Planes trains and automobiles. That's what i watch, that and the jazz music channels.
It's Like Changing A Bulb In A Set
Of Christmas Lights.🚦🚥🎄
Dave,
I like that short is quick and to the point. Long sometimes has some juicy nuggets of information. Your choice. Question: Are all fluorescent displays powered this way?
Thanks a lot, Tom
Yes the 20 min version is great. When you are editing your earlier vids...you should do a blooper reel of the times you snapped. Those were some of the best parts of the earlier vids.
I have a GE Sapcesaveer microwave with a VFD. The left side is pretty good, and the right is very dim. I don't have a schematic. I suppose I need to get in there and compare voltages, then guess which parts to pull and test.
Yes sir pls do upload short version of your previous videos. Thanks
love it
Great video as usual. I own a Panasonic saak 29 shelf stereo that sounds great but the display is very dim and the tech I took it to said that the fossils itself was bad but was wondering if you might have a different opinion on the matter?
Thanks a lot!
Good stuff, easy fix.
I like the longer videos, i've learnt a lot watching them especially the ones that take you a while to find the problem, it's given me a few tip's for what to look for with cassette decks, I started buying them and repairing them after a neighbour gave me a 1978 pioneer ct-200, i've now got 17 and 14 working, any tips how to replace the sensor bulbs on sony tc-v7's would be much appreciated
I agree, the longer videos are my favourite. I like your rationals, explanations of your approach, and detailed thoughts you had to resolving the problem. I also like seeing your testing tools, and your diagnostics. So I vote to keep things the same. Thanks for making it look easy, even when it’s not. Also like it when you talk about your parts, substitutions when original not available etc.
@@12voltvids Ignore the people who say they want shorter videos. Your true fans want the long in-depth videos. Anyone who wants shorter videos isn't interested in actually repairing electronics.
@@petenamlook18 I hear you. Short videos are not coming any time soon, but shortened versions of older videos may show up with irrelevant material removed from time to time.
Can you do a video about cd LCD missing numbers and motor tray noises
Great video, Dave, this is good to know for any future repairs! BTW, what brand of your ear meter and the other one, capacitor/ vom meter ?
Very interesting receiver
Huh? Don't VFDs get weaker with age? I mean, by prolongued usage?
Was this case an exception?
Yes they fade with age. Some faster than others. I have a clock that the vfd failed. I changed it for another one i pulled from another clock module that i had used the chip to make a jumbo display clock.
@@12voltvids Unfortunately I can't do the same thing with my AKAI DT200 timer. They're rare to find and would cost just as much to get!
I was secretly hoping you had a magic solution for reviving VFDs!
@@Stelios.Posantzis you can raise the filament voltage slightly. That will heat the hot cathode and create more emission but this is a temporary fix. Most last a long time. I have some displays over 40 years old still relatively bright. It depends on the tube. I built a 6 digit VFD clock a couple of years ago. Perhaps 3 (the build is on my channel) and the 10 minute tube is so dim it barely shows now. Depends on how well the tube was made. Good tubes last a long long long time. The original one from my 1979 RCA VCR is still good . When i scrapped the VCR i made a clock out of it. Still works and it is 42 years old and bright as anything.
Good idea to shorten some videos, look for the fault, fix it done.
Some of the older ones are too long and will be redone at some point. I will be editing off the source files, so it wont just be a shortened video, and most of the audio will be dubbed in to explain what I am doing as I did in this one.
@@12voltvids That's fine, perfect. What stops me looking through some of the older stuff is they are just to long. I just want to see the fault, finding it, fixing it and seeing it work (but not a long working bit) and that is it. It will also allow other to look through some of the older ones, plus, you will get adverts twice for one video :-))
i get the same with my esr tester time to time.
Great
i'm confused you had a unit dim display you said could'nt be fixed
Where did I say it couldn't be fixed
Good one!
You are Awesome.
Cool to know you need to run all 3 cap tests to confirm a cap is REALLY bad of not.
Yes ESR, Capacity and ohm test.
@@12voltvids let's not forget DC leakage current test! Which is what that capacitor you replaced was suffering from! And there's no other way around it, they have to be removed to be tested! They usually show up as having good ESR which throw's of a lot of people as not many people seem to know about that failure mode and therefore don't have the means to test for it...
@@PeterMilanovski
No this one shorted. Not leakage. Leakage was really only an issue in the wax coupling caps in tube gear. Electrolytics generally do not go DC leaky unless they short completely as this one did.
@@12voltvids actually you might be surprised, modern electrolytic capacitors are also leaky, the one that you pulled out was really bad! I can't remember if you had one of those cheap Chinese multi component testers, those things usually give a Vloss reading when testing capacitors, this is a great test feature that the majority of people who have one don't even look at the percentage of Vloss because they don't know what it's for or what it means...
The old wax paper capacitors do leak... But you have to remember that those things were way underated! You can easily put twice the rated voltage across it when new and it will be fine, try that with a modern electrolytic capacitor LoL... It's also the reason why the wax paper capacitors lasted so long! If you do the same for your own equipment, replace capacitors with twice the rated voltage or higher if the size allowed, your equipment will last a lifetime!
I have tried various methods for testing capacitor leakage current, from an LCR Bridge Meter to a simple Lab Power Supply with a uA analogue meter showing up the leakage current..
Sure! You might say that a few uA of leakage current is nothing, well... I can tell you about an article that I read in Electronics Australia, I believe that it was from the 60's, manufacturers were trying to move away from using a traditional transformer in the power supply of TV's in order to cut costs. The new TV's were going to use a half wave rectifier as the power supply, the only problem with this was that the Melbourne board of works tested this as the galvanized pipes used back then were actually the neutral to the electrical system in the house. This new style of TV was sending mA of DC current on top of the AC which caused a brand new galvanized pipe in the ground to rot within a week! Due to electrolysis. There had been a few of these new TV's sold in the country but it wasn't long before they were banned from the Australia, the government bought back the ones that had already sold, it was also found that the small DC leakage current was causing the transformer on the power poles to overheat! Hence the reason why a vacuum tube amplifier has huge output transformers! You essentially have both DC and the AC ripple which is the music that's going to make it across to the secondary side, if you can figure out how to get the DC off the output transformer, which has been done, you can get away with much smaller transformers, so basically.... The less that a capacitor leaks DC current, the better! But first you have to be aware of this particular problem and then have the equipment to identify it...
You can probably tell that I have spent far to much time on the topic of capacitor failure... I used to use an ESR years ago and while it seemed to work great, every now and again I would run into a piece of equipment that should for all intents and purposes work properly but doesn't! This drove me nuts! So I went on a research bender and found that a leaky capacitor is worse than a capacitor with high ESR!
Now! I always check them on an LCR Bridge Meter, the one that I use shows all the details on the one screen! So with one glance, I know exactly what condition it is in.. and I have never had a problem since!
When it comes to equipment from a customer! It's always up to them for what they want to achieve... But I always give them the opportunity to choose... You would be surprised how many people would choose to spend more money when they realise that if their equipment is done properly, it's cheaper than replacing it with something new that will most likely be more difficult to repair... The old one lasted 30 years, the new one will not! And I have never advertised! It's all word of mouth... You have an amazing skill, your ability to fault find is second to none! But you have to keep an eye on capacitor DC leakage current... It's a real silent killer... Let alone electrolyte leakage and expansion, high ESR and all that... It would be so much easier if we didn't need them but we haven't found a good replacement... All we can do is keep those soldering irons on standby LoL.
@@PeterMilanovski On low voltage low impedience circuits this just isn'r an issue like it was on vacuum tube gear. The problem with paper caps was the paper. As it aged acid in the paper from the time it was manufactured gradually turns the capacitor into a resistor.
With a high impedance high gain tube circuit it only takes a few microvolts to tickle the grid of the next stage and cause a high dc plate current. This will reduce the life of the tube, and in extreme cases burn out transformers. Solid state circuits this is not nearly as big an issue. Hot chassis leakage is a totally different issue. We had the same problem here, but it was due to submarine DC power cables. Was eating underground pipes. The power company has installed negative electrodes into the ground to mitigate this problem. Firthermore they used ground return. So just the positive wires were sent from the mainland to the island. The negative retudn was a series of electrodes at the shoreline which then went Ariel back to the substation where the rectifiers were. Not all the currents went to these electrodes, so additional kathode electrodes that were fed with about -48v were installed to prevent pipe degradation. Where I live, if you drive 2 ground rods into the ground seperated by about 30 feet, you will have a small differential voltage between them, and can actually pull several amps. All ground electrodes need to be bonded together. This is actually done every 300 metres on all the poles. The multi ground neutral is bonded on every pole that has a transformer and every 300 meters.
Hi sir,
I've a Sony MHC- W550 mini hifi home audio system, I'm facing same problem with it's display. The display is too dim, plz give some solution, thank you 🙏
Check the supply voltages driving the display. If ok then the display is bad.
@@12voltvidsAll is not necessarily lost though. This video and all the tips you gave were much appreciated. I have an old Yamaha RX-V390 receiver with a dim display, but all the voltages checked out, and I was resigned to the fact that the age of the VFD was the root cause. However, during reassembly, I noticed that there was a strip of orange film covering the VFD. I peeled it off, expecting the VFD to be brighter but with all the electrodes visible. Not at all. I assume that the designer did not like the blue green colour for some reason, set the VFD circuitry to max brightness, and then put an orange filter on the front of the display. I accept that this may only give me a few more years use, but I'm happy with that.
@@davidwhite9751 must of been one of these blue light snowflakes. Sorry but when someone tells me to put a blue filter on my phone because it is bothering them at the next table I am more likely than not to tell them to eff off. Yes that happened to me once. sitting in a restaurant by myself waiting for my food to come I was surfing around on my phone like a lot of people do. Women sitting at the next table with some little kids has one if the kids whisper something to her then she gets up walks over to my table and asked me to turn down my screen brightness or turn on my blue filter as it was bothering her kids eyes.
Guess what i did so apease her.
Yup started surfing the twitter feed milfs, juicy mins ect making sure to hold my phone up high enough for them to all get a show.
Some people. They should just mind their own business.
Bothering little Johnny's eyes. Give me a break. Perhaps if he was sitting in his seat instead of standing on the bench looking over my shoulder at my phone this wouldn't have been ab issue!
I Did That To A Little Cheap Transister Radio.
The Radio Sounded Kind've Crakley
So After I Did That The Radio Sounded Great.
I would love to be your student so I can learn how to fix all those jvc vcr I'm planning to buy
First to watch this clip. Regards
You Only Had To Swap Out 1 Capaciter. Cool
Just finished watching the longer version after this short one and I think that I prefer the longer one!
It might be a good idea to create a second channel that contains all the short versions, some people like them short and others who need to make a similar repair need the long version!
I noticed in the long version, you tested a 100uf capacitor and got a reading of 105uf... A good capacitor should always read right on the mark or just below it!
If it's reading above, it's leaking DC current! ie a short or close enough to a short!
The ESR meter is only looking for high ESR and nothing more!
A shorting capacitor will always return a higher value due to the short appearing to charge longer than it would if it was not shorting... They have to be pulled from circuit to be tested, there's unfortunately no easy way around it!
You can quickly go over all capacitors in circuit with the ESR meter but that doesn't tell you everything! As soon as you called out 105uf for a 100uf capacitor, I knew straight away that it's a leaker! There's no such thing as an over achiever when it comes to capacitors!
Go back to school. Capacitors can be 10% under and 20% over. That is the tolerance on electrolytic. So a 100 can measure between 90 and 120 right out of the box.
Starting another channel is not an option because I would have to meet the eligibility requirements to monetize the videos. The new edits of old videos are for those that complain like spoiled brats about videos being too long. For every person that says they like the long version 20 say they like the short version better so you are in the minority.
@@12voltvids I have never measured a new capacitor that was over its rated capacity, only old used capacitors that show low parallel resistance.. but to see that in the first place, first you need the right tools, you can't use a multimeter! It's not sensitive enough! If a multimeter can see it, that cap is bad...
Either you have a Heathkit or Eiko leakage tester, or Paul Carlson's capacitor tester which tests for leakage or an LCR Bridge Meter... Some of those Chinese multi component testers will give you a Vloss % reading, it's better than nothing and can identify parallel resistance much better than a multimeter... You call it shorted, this is exactly what low parallel resistance is! It can be so low that a multimeter trying to measure resistance isn't going to be able to do it and just gives you a short reading...
I'm sure that you have one of those multi component testers, it's possible that it shows the Vloss reading when testing capacitors but you probably have never taken notice it, it's telling you at what percentage it's shorted, compare some old capacitors that you might have laying around to the same thing in new one's... Actually, make it a video! I don't know what it is but people love watching bad capacitors being treated and compared to new! I would definitely watch that....
@@12voltvids well you are the creator! Kinda like a god LoL, it's your channel at the end of the day and you should do whatever you wanted to achieve!
The people who like the short video just want to see the fix, they are not interested in who you are. For those who like the longer video, I think that they are the loyal viewer, they enjoy the fix and anything else that you have to say...
@@PeterMilanovski and there are both versions. The new short versions are remakes of older videos and the old ones are not going away so don't worry, because there will be longer videos still made.
i like the long videos i find you lern more
Not necessarily. You don't learn anything watching me take the equipment apart unless there is a specific procedure.
You mean voltage tripler. .
I'm shocked that the esr tester was telling lies or omitting d.c resistance/leakage.
That has to be rare, that tester has worked really well for many years.
I've never found any fault with your videos.
Years ago i tryed to watch mr carlsons channel, Way way too much waffle about nothing.
ESR and low ohms. They measure with Ac at about 100khz. A good cap will look like a short to an ear meyer. That's why you have to test with both dmm and esr or you could miss something.
@@12voltvids A good cap will look like a short to a what? 🤷♂️
@@rogerwilco5187 a good cap will show very low resistance on esr tester and will charge up on ohms to infinite as capacitors block DC.
@@12voltvids Yes but what is an ear meyer?
@@rogerwilco5187 it's an esr meter typed on a phone screen because you know the phone is smarter and corrects spelling.
1 Goes Out The Whole Set Goes Out.
I didn't think you can trust a ESR meter.
Of course you can. ESR going up is the first sign that a cap is starting to fail. The only time an esr meter won't work is in the event of the capacitor shorting internally and in all my years of servicing i can tell you i have more fingers than the number of times I have see a cap dead short. In 10 years i have seen it twice. One was the main filter on a power supply.
But half of the charm is when you get grumpy because of bad craftmanship, or cheap chinese parts, or dealing with ppl... u_u
The number of failing video clips you have in the intro section, makes me think I shouldnt leave my electronics to you? lol.
Well considering all the clips in the intro were staged.
@@12voltvids okay. :) was just joking. I know u have great knowledge!
@@Shamsithaca so was i!