Must be cool to know your video is still helping people 8 years down the track. Fixed my problem and saved me a truck load of cash. Thanks for sharing.
Having been born in '88 I may be young to say this, but it's always refreshing to see someone else willing to attempt to do a repair (or at least failure analysis) on goods more often considered "disposable" these days. Honestly, 75-80% of the time I just want to know why it broke. The potential reward of being able to return the thing to working order is merely bonus points.
Hey Big Clive... love your channel. I have nearly 45 years of hobby/professional electronics experience, and VFDs have always been one of my fave components. I have a few bare VFD tubes in my parts box that have been there well over 30 years... I just don't have the heart to dump them. I wanted to comment on you finding AC on the cathode heater element. Any properly designed VFD circuit will use some form of AC or switched supply. The problem with a DC filament supply is that, as you pointed out, there is typically about a 1.5 - 2V drop across the heater. This means that the cathode voltage will be 1.5V higher at one end than the other RELATIVE TO THE FLUORESCENT ANODE. This makes the display brightness vary noticeably across the face of the display. Using an AC heater supply will give an AVERAGE voltage at ANY point on the cathode of half the total voltage, which solves the problem. You don't need a sinusoidal AC supply, in most of my old VFD designs I just switched the two ends of the filament 180 degrees out of phase. You can use an H-Bridge for this, but depending on the size of the display you can often get away with using a resistor to Vcc on either end and a bipolar transistors to alternately pull each end down to ground while letting the other end get pulled up to VCC. As long as you alternate the drive circuit fast enough the switching filament voltage will be smoothed out by thermal inertia and you won't see any flicker. Cheers.
Thanks for sharing this video really helpful. My failing AEG oven timer unit had the same fault, resetting itself with a constant buzz noise. Replacing the capacitor saved the money and brought the unit back to life.
So, I was just over at Ashens and they're talking about you in the comments, Clive. Apparently your voice is calming and your videos are great, even though they don't know anything about electronics.
So bizarre, long time follower of big Clive, & when “I needed to find a fox for an old cooker he comes with the fix in a video from 8 years ago , thanks mate your a diamond, cap is ordered..
I seem to remember that running the heater wires on dc will work but it makes one end of the display dimmer. A.c makes sure that does not happen. Well done clive, a simple fix ;-D, and that capacitor looked ok as well, deceptive.
+zx8401ztv Had the same problem with my refrigerator. Whenever you opened the door, the light would turn on, then the whole fridge would go dark (incl. the temp. display) and light up again only to go dark again and so on. It was also the X2 dropper capacitor. A 2€ piece. If I had called some company, they would've switched the whole control unit for a few hundred €€€.
+Markus Birth (mbirth) Oh yes they would, ripoff merchants :-( Often things fail for silly reasons, some are obviously planned like electrolitic capacitors with a short life (switchmode psus). . I think for your x2 capacitor i would get two capacitors of half the capacitance value and parallel them to share the work. I dont trust manufacturers much.
+zx8401ztv Yes, that is the problem of supplying DC to VFD. If I recall good, different "cooking" of the electrodes as well. The film capacitor usually fails like that, lowering value, unlike electrolytic which get dry, increase ESR and end up popping. Advantage: you don't need an ESR meter :D Also it is a must check when repairing ballasts and half-bridge power supplies where a film capacitor 'suffers' all the current trough it.
+Electronica y Reparaciones Ooow im thinking about the capacitor that connects to the half bridge primary winding end, i think that is the one you are hinting at :-) Typically 1uf in value for small supplys?
Big THankyou for this repair advice. Just saved me over £100 . replaced a similar capacitor to yours, had to order 5 though. Wonderful. Keep up the good work.
"If you want to pull your nob off in front of the oven..." I had to stop the video as I was laughing too hard. Now go back and re-watch the first minute of the video and listen to one of the best monologues in TH-cam history!
they use AC on the VFD filaments because it prevents one end of the display being darker than the other. If you put DC on the filament, one end will be brighter than the other- the end closer to ground. This is because there is a voltage gradient across it then. Noritake had a cute trick where their later VFDs run DC on the filaments and they compensate by tilting the filament so it's closer to the grid on one end and farther apart on the other.
+kevtris Years ago I messed around driving the filament with a hefty pulse in between driving each digit. Not sure if that's an officially sanctioned way to do it, but it did work. It meant that while the digits were driven, the filament had zero gradient across it. I had some trouble though, the microcontroller I was using did not have a particularly high clock frequency, and if I ran the timer at a high enough frequency for the pulses to be above audible frequencies, I did not have enough resolution to accurately control the filament power. Of course there are ways around this, but I was just mucking around in my spare time. There would be concerns with fatiguing the filaments etc.
yeah this is possible; the filament doesn't care how it gets heated, so long as it is hot enough to emit those electrons. I like the idea of pulse heating it to prevent the gradient though, that's a great idea!
Ah, this has got me thinking about VFDs again... For a while I have toyed with the idea of designing up some hobbyist type modules using the various inexpensive Soviet VFDs that are available. Everything on-board, only requiring a 5V power supply and data via SPI or UART. Full Arduino support etc. Target RRP of somewhere around US$20/pc. I would peddle this through the usual channels for such items. But I am really unsure if this would be desirable... Comparable items were quite scarce last time I looked for them. May I ask for opinions on this matter? Edit: Had another look. There have been some reasonably priced, fairly capable looking modules released but it appears they did not do overly well. Perhaps this ship has flown.
I fixed a Siemens wireless heating controller a few weeks back and it had the same dropper capacitor and the same failure mode exactly. I ordered a replacement cap from Farnells and had the exact same problem with the footprint as well!!
Don't know why I've never watched this video before, thought I'd watched all of your earlier ones. Seems I missed a bit of a classic, too! I prefer to tug my knob off in front of the microwave, it's quicker!
*glorious* I have a very similar oven clock at home and got annoyed by the constant buzzing sound it makes. (and that it consumes power for nothing.) Brand: Diehl 131 47-001 Typ: 311-20 T120 Props to you for showing how to further diagnose and possibly fix such a device. I just disconnected it. (but was curious enough that I did find your video.)
Interesting introduction...! Yeah, Creda cookers from the 90's have these. I could never understand why there was never a battery-backup for the timer. A power-cut lasting only half a second will reset the time to 0:00, and also wipe your oven Auto on/off settings. Even a large electrolytic cap would give a little buffer, but everything costs money I suppose.
VFD heating filaments are mostly AC driven to avoid uneven illumination. When for example the heating voltage is 6 volts and the driving voltage is let's say 30 volts then the voltage drop across the heating filament is significant compared to the driving voltage. 30 volts on one side of the display and only 24 volts on the other side. Thus they are AC driven to lessen this effect.
My failing AEG (Electrolux) oven clock had exactly the same fault. It's another common unit with LED display and three buttons. It would constantly re-set itself and the relay would buzz away like a mad thing. The dropper cap was kaput and replacing it brought the unit back to life. Saving £70 ish !!!
Where I work we would say, "Cap it!" meaning replace all of the stupid things. Cheap insurance when the work is warranted for 2 years! ;) Thanks for the VFD explanation! I understand that people have used the large complex ones to build audio amplifiers and such. They really do seem pretty cool.
+Max Power Years ago I saw that used in a TV repair shop and tried it myself, not so successfully. A little daily practice and about a week later it was if I had always been doing it like that. Nowadays it is not so easy what with lack of practice and older hands although it still beats trying to use those third hands and assorted fixtures for small items. Mike (o\!/o)
Max Power Just practice manipulating small items like screws and nuts, tying knots, etc. Soldering can wait until you are able enough to not have to endure burns and the like. Kind of like juggling, don't start with chainsaws. Mike (o\!/o)
I didn't know about the reactivation trick by passing a high current through it, but the same trick is used to clean the filament that emits electrons in scanning electron microscopes ("flashing"). The vacuum gets contaminated and the filament gets coated with crap; passing a high current through it just burns it all.
so if you use a 3.3uF capacitor but instead of 250V or 400V, you use a 630V cap, it will have ticker insulation so would it last longer under regular 240V conditions than the 400V? if I use a 630V cap on my 120V supply will it last much longer?
If you have the same issue with an oven which is similar to this you can check get your main oven to work by disconnecting the two tags on the relay which looks like the one on the left hand side when the clock is rotated around showing the back and connecting them together. This will bypass the relay which will activate when the clock is set to allow you to use your oven. This is a safety feature to prevent the appliance from automatically powering up if you had children who like to fiddle or you had a power cut for example.
I didn't get any of the innuendos at the beginning, didn't notice anything wrong with what you said until I read the comments. I guess I'm not as dirty and/or bright as I thought. On a completely unrelated note - Clive, could you please show us some overview of your workbench? I would love to see all those bits and pieces you pull into the shot every so often.
I've got a Beko oven and the module started doing a rapid reset. I had a quick look but didn't determine a fault, so bypassed it to use the oven. I will revisit this as it will most likely be the cap. Thanks! While I'm at it, I'll pull my knobs off. Oo-er.
As I followed the instructions about pulling the knob off.......it quite took my mind off the broken timer and it's repair, many *anks.....sorry, I meant thanks.
+Ben McKenna Clive is the best one on TH-cam doing tear downs, reviews and repairs. Julian Illet is good too! John ward does my head in, irritating little man, I just watch him to fill my hump of hate lol. Usually get a laugh with Clive though.
I used to work for Currys and often noticed how different appliance manufacturers used almost but not quite the same layout for controls and I do agree that the optional extra (but unused) contacts are likely there for use on different models, even different makes, even where Swedish Megaconglomerate Inc. hadn't even bought out (yet) Howthehelldotheycompeteonpricewithsuchsmallvolumesales of Wednesdbury West Midlands UK ... (before they went bust of course). Highly entertaining video as usual!
+Robert Horwat In my base-model Indesit washing machine the control panel has a PCB with all the locations for the extra knobs and buttons used on the "luxury" models with the only major difference being a different front panel and different software. (Which can be programmed from the back of the machine.)
+TheChipmunk2008 Yeah and they use to warn that there was no guarantee it would work and that it may destroy your tube still cheaper back then to give it a go. :)
+TheChipmunk2008 They act more like a vacuum tube. The grid is like the grid, the digits like a plate, and the heater like a filament. Just like a tube, the filament/heater is thoriated. The thorium lets you have electron emissions at lower heater temperature. With the filament at a lower temperature, you get a longer life and don't obscure the green digits with the heater glowing like a lightbulb. When you overdrive the heater/filament you "boil" more thorium to the surface.
"If You Want To Pull Your Knob Off In Front Of The Oven, What You Have To Do Is Gently Caress It Between Your Fingers And Then Just Pull It Gently Until It Comes" - Oh yes, Clive, I liked your technique though I'm not sure if the oven was suitably turned on by the experience. Well, the Quick Test has shipped, it was purchased from RS Components in Sydney. Its first job will be for fixing and testing a motorised roller shutter motor. Weird thing was two vastly different prices for the same unit, but under two different SKU codes.
I worked at Invensys, I have no doubts about it being a QC problem. Rumor was they lost a contract once for sending a shipment of test failed boards to a manufacturer.
+ bigclivedotcom to release fiddly PCBs like that easier and with less risk - first warm the enclosure with a hairdryer for a few seconds to make it less prone to cracking. Then gently lever with a screwdriver like you did, but push cut-down bamboo BBQ skewers in next your screwdriver before you withdraw it to prevent re-latching. Trim some of the the sharp tip off the skewer with a side cutter if you need them thicker/if the thin tip is too long. Don't snap them - the splinters are very sharp. The hairdryer technique works great for many types of thermoplatics to make them less brittle when you release clips and is especially important in cold rooms or if the kit has been stored at cold temperatures just before you need to open it.
Fixed an LED-based one for a friend a year or so back. Same problem - the 1u0 X2 dropper cap measured 620nF which was more than enough to stop the relay pulling in. Seems some brands of X2 caps are prone to this kind of failure. Edit: And of course when used as a filter a dramatic drop in capacitance would probably go completely unnoticed.
Driving the filament with AC is better than DC, because with DC you get a voltage gradient from one end to the other, and that results in one end of the display running a little dimmer than the other.
The construction of a VFD is akin to a triode valve - filament, grid & anode. And folk have been able to make it amplify an audio signal, albeit weakly, or to oscillate.
Clive - I was on Patreon.com a few minutes ago checking on my pledge-ees. Then I suddenly remembered, Clive has a Patreon account!! So I immediately became patron #470!! Do you have a new pledge goal in mind? I see the last one was reached. Thanks again for all the great stuff, Clive!!!
You may like to know that I used to be in charge of spare parts for a company that serviced white / brown goods. Those timers are pretty standard and cost £4.95 each for the company to buy, they would charge the customer £120 to fit a new one and that was way back in 1996
I'm pretty sure DC filament drive is only really an option for short VFDs as it causes a potential gradient between the filament and the grid. AFAIK the filament should be driven with AC.
+Mezgrman Yes, came here to say this... DC on the filament causes the display to vary in brightness across its length. Have seen it before in some VCRs
I used to use dentist drills to drill PC Boards. They give very clean holes of a perfect size, and you can get them for free from your dentists, if s/he is willing to put them aside for you.
Clive, it would useful to shed some more light on refreshing these tubes to get better display brightness. I am sure many DIY types who refuse to buy new, simply because of age or style superseding older, perfectly good machines. A testament to the quality of Samsung brand this mid range unit must be near 20yrs old, and though it was a trick to source the control/display module, most listings have it as discontinued or out of stock. Not cheap either. This microwave owes me nothing, but recently have been boiling stuff I only meant to reheat cause I can't see miskeyed input on the display
+Chris Leech emission may be restored by raising the filament voltage. a 33% voltage boost can rectify moderate fade, and 66% boost severe fade. The displays were designed for rugged use.
+Jeffery Rowan Thanks for that. I am going to have the unit apart to fix the door release and will do a bit of probing with a DMM to see what I have got . Mine has a few more functions and will be a little more engaging I should think. Does one need to limit the current I wonder. All I have is variable buck and boost converters running off LiPo's to get these voltages.
Very interesting, timer module de Dietrich oven displays oven temperature set point and actual temp, crystal display, single button, knob to press to scroll between timer modes. When we press the button it no longer scrolls... Would be interesting to have your skills. Unbelievable with same oven , oven light stays on,when the off zero position is selected on cooking mode selector. De Dietrichs are dear and parts scandalous. Delighted to subscribe to your channel, i might learn something!
+grmlje grmone I have an Owon digital scope that I occasionally use. To save time and trying to make it visible under the lights I print off images from it for the videos.
I have a few of these displays, but it's doubtful that I will ever do anything with them. In particular, I've never run across any that were fairly generic, in the way that 7-segment LED displays can be. From what I understand they're all pretty much custom-made for the item of equipment that they're going into. And I haven't (yet?) run across any good technical info on these devices in general, or specifications on any specific devices.
I think most devices with VFD displays run AC current through the cathodes. If it was DC, then one side of the display would be brighter than the other.
Whenever I repair anything with those rubber buttons with conductive studs, I clean them, and the PCB pads with meths. Most TV remotes use them and they often become inoperative after a while.
Excellent video. I have a similar timer module on my oven, where some of the segments on the display have stopped working. Consequently the display time is illegible. What would I need to do to repair the segments that don't light up please>
I had the same fault on my cooker, in fact that module is identical to the Cooke & Lewis one I repaired, I guess they are all made in the same factory,think the capacitor cost £1.32 from eBay compared to £94plus Vat B-Q quoted.
The dropper capacitor going low in value over time is a really common fault in all sorts of appliances. It's the first thing to check when the product becomes intermittent or drops dead entirely.
Its common for vfd's to have ac across the heater, in fact its better for them. DC introduces a voltage drop across the heater wire making a brighter display at one end, this isnt as bad with ac. Proper vfd drive chips that run off dc produce a square wave for the heater using a H bridge.
I have one in my cooker, but it has 4 buttons plus an encoder. And to set the time you press cook time and end time together. Clever little thing, I've always wondered whats inside.
First impression was partly shorted electrolytic capacitor, shunting voltage. Yet, if cap dropper fixed it, it was current issue? In either case, main input voltage or current was obvious. This because even the piezo and relay was buzzing. I've seen too many such defects as low negative supply rail as being one of the electrolytic caps being partly shorted. Anyway, as long as circuit is up and working again and relay latches as it should, its fixed.
Do you have one of those cheap ebay LCR meters? I got one for about $10 in kit form that measures ESR. It seems to work, but I don't have a decent ESR meter to test it against.
Hi, there is a SMD component close to the rectifier bridge. It has marking QX 09 V. Any idea what that one is? A shottky? If so.. what is kathode and anode? Mine measures high impedance on both sides
firstly... "if you want to pull your knob off".. coupled with "you have to gently press it between your fingers".. then adding "pull it gently before it comes"... was that planned? if so rofl!It'd be great if you could tell us how to replace a thermostat on a microwave though... I've killed 3 thermostats in as many combination ovens and it's getting too expensive coz I don't know how to replace 'em.. please help! You're the man!
I *really* like VFDs, it's a damn shame they're few and far between as far as manufacturers go. Noritake did a promo a while back where they gave away like 100 of their new VFD modules, but barring another one of those, they tend to be *very* expensive for nice ones, since the market's been taken over by x-segment LCDs.
Both informative and entertaining but the main thing I like is that it is in proper English (OK, Scottish but that's fine) not USA-ish, which grates on me unbearably, especially when solder is called "Sodder" The innuendo i also appreciated.
Hi, I have a question ... This module has 4 wires: on the left side (where you connected the test cables) are the Live and Neutral. On the right side above is neutral too and the other one is for? Is it DC or AC? How many V are there?
+Gadgetboy I just gave up and bought a Hakko desoldering gun. I love the thing. Nothing like it when I have to desolder chips or a whole lot of parts. I once had to sit down and remove USB connectors from 200 boards. The Hakko does such a good job that when I finished the last pin 9 times out of 10 the part just drops out.
Was that capacitor at around 4:40 Iskra branded? I didn't know that they were still in business. It's an old Yugoslav company that used to make all kinds of electronics equipment like multimeters, oscilloscopes and soldering stations.
Lovin' your videos Uncle Clive :) But for whatever reason I became curious, whilst watching this video, about just how you record/produce them. I do remember you mentioning an iPad, but how are mounting it, and are you actually viewing via the tablet's display as you work. A quick mention in next video would nice. Thanks Clive. Always look forward to see what Uncle Clive's up to as part of my daily wind down. 😊
+MickeyDJ1 I ahve a shelf at the correct height above my bench to give the correct recording area, and the iPad sits across two pull-out slides. I have it high enough to work directly on what I'm doing, but can also check what is actually being seen too.
Hi I've got one of these and replaced the component as you have done. I see that the relay looks a little brown and get no continuity across it, so suspect that has failed. I'll order the component and try my luck.
By any chance do you know the DC voltage out of the rectifier bridge? I am getting 0.5 volts and there is no way to know the real value of the two zener diodes test them and one is 12.3v and the other 2.3v
How can I get someone to fix my cannon double Oven cooker. The module button not setting the time hence I can’t turn the oven on and no gas. Any recommendation or time for new cooker? Thanks
Where is the connection to the temperature sensor? I though that was a oven controller. It has the relay to start turn on the heat, but no way of detecting the temperature.
Bigclive can you please explain how to fix a solar light that stays on all the time. I have cleaned it all out stays on in daylight and flattens the battery Thanks
Hi Clive, I've only recently discovered your channel, and I've been binge watching while off work recovering from flu. I must be on the mend because this morning I decided to tackle something that's been bugging me for a while, an intermittent fault with our oven timer. The problem is compounded by the fact that the oven has an auto-spark, and when the timer drops out the oven goes out, and we often get a on-off-on-off dance from the cooker when the oven is switched on, and it's warmed up, meaning that the oven is unreliable. While searching online for a replacement timer, or method of bypassing it (we don't use it), I saw, there in my search results, a video thumbnail, and I exclaimed aloud "it's BigClive!", I thought if anyone would have a solution it would be you. So I watched the video, but my timer is a different model, there are similarities, but not many. Anyway, watched the vid, paused, looked at my timer, watched some more, paused again; I eventually spotted a dry solder joint - I know how to fix that! Out came the soldering iron that I've not used in nearly 40 years (I used to build guitar effects pedals when I was a teenager, but they never worked - hence the lack of use for the soldering iron!), and the solder. I let it all warm up applied heat and a little solder, and hoped that lack of practice had improved my soldering! I connected it all back up, powered up, looks good. Turned on the oven, ran it for an hour, used the alarm timer several times; hey! it works! Thank you so much for the very enjoyable channel, and getting my cooker fixed for free!
Must be cool to know your video is still helping people 8 years down the track. Fixed my problem and saved me a truck load of cash. Thanks for sharing.
Having been born in '88 I may be young to say this, but it's always refreshing to see someone else willing to attempt to do a repair (or at least failure analysis) on goods more often considered "disposable" these days.
Honestly, 75-80% of the time I just want to know why it broke. The potential reward of being able to return the thing to working order is merely bonus points.
I cannot believe you got away with those opening lines. Pull the knob off etc. You are a bad (and funny) man Clive :)
Hey Big Clive... love your channel. I have nearly 45 years of hobby/professional electronics experience, and VFDs have always been one of my fave components. I have a few bare VFD tubes in my parts box that have been there well over 30 years... I just don't have the heart to dump them. I wanted to comment on you finding AC on the cathode heater element. Any properly designed VFD circuit will use some form of AC or switched supply. The problem with a DC filament supply is that, as you pointed out, there is typically about a 1.5 - 2V drop across the heater. This means that the cathode voltage will be 1.5V higher at one end than the other RELATIVE TO THE FLUORESCENT ANODE. This makes the display brightness vary noticeably across the face of the display. Using an AC heater supply will give an AVERAGE voltage at ANY point on the cathode of half the total voltage, which solves the problem.
You don't need a sinusoidal AC supply, in most of my old VFD designs I just switched the two ends of the filament 180 degrees out of phase. You can use an H-Bridge for this, but depending on the size of the display you can often get away with using a resistor to Vcc on either end and a bipolar transistors to alternately pull each end down to ground while letting the other end get pulled up to VCC. As long as you alternate the drive circuit fast enough the switching filament voltage will be smoothed out by thermal inertia and you won't see any flicker.
Cheers.
Thanks for sharing this video really helpful.
My failing AEG oven timer unit had the same fault, resetting itself with a constant buzz noise.
Replacing the capacitor saved the money and brought the unit back to life.
Just cheked a certain 'E' site for those and I'm shocked Clive - they cost so much!
I love fixes more than buying and this is so simple. Cheers!
So, I was just over at Ashens and they're talking about you in the comments, Clive. Apparently your voice is calming and your videos are great, even though they don't know anything about electronics.
So bizarre, long time follower of big Clive, & when “I needed to find a fox for an old cooker he comes with the fix in a video from 8 years ago , thanks mate your a diamond, cap is ordered..
I seem to remember that running the heater wires on dc will work but it makes one end of the display dimmer.
A.c makes sure that does not happen.
Well done clive, a simple fix ;-D, and that capacitor looked ok as well, deceptive.
+zx8401ztv Had the same problem with my refrigerator. Whenever you opened the door, the light would turn on, then the whole fridge would go dark (incl. the temp. display) and light up again only to go dark again and so on. It was also the X2 dropper capacitor. A 2€ piece. If I had called some company, they would've switched the whole control unit for a few hundred €€€.
+Markus Birth (mbirth)
Oh yes they would, ripoff merchants :-(
Often things fail for silly reasons, some are obviously planned like electrolitic capacitors with a short life (switchmode psus).
.
I think for your x2 capacitor i would get two capacitors of half the capacitance value and parallel them to share the work.
I dont trust manufacturers much.
+zx8401ztv There's a video specifically about their failure mode. th-cam.com/video/qGc9-ToEiIQ/w-d-xo.html
+zx8401ztv Yes, that is the problem of supplying DC to VFD. If I recall good, different "cooking" of the electrodes as well.
The film capacitor usually fails like that, lowering value, unlike electrolytic which get dry, increase ESR and end up popping. Advantage: you don't need an ESR meter :D
Also it is a must check when repairing ballasts and half-bridge power supplies where a film capacitor 'suffers' all the current trough it.
+Electronica y Reparaciones
Ooow im thinking about the capacitor that connects to the half bridge primary winding end, i think that is the one you are hinting at :-)
Typically 1uf in value for small supplys?
Big THankyou for this repair advice. Just saved me over £100 . replaced a similar capacitor to yours, had to order 5 though. Wonderful. Keep up the good work.
my display went 6 month ago, i took it apart then i never got around to fixing it! Good video
"If you want to pull your nob off in front of the oven..." I had to stop the video as I was laughing too hard. Now go back and re-watch the first minute of the video and listen to one of the best monologues in TH-cam history!
😂😂😂
they use AC on the VFD filaments because it prevents one end of the display being darker than the other. If you put DC on the filament, one end will be brighter than the other- the end closer to ground. This is because there is a voltage gradient across it then. Noritake had a cute trick where their later VFDs run DC on the filaments and they compensate by tilting the filament so it's closer to the grid on one end and farther apart on the other.
+kevtris Years ago I messed around driving the filament with a hefty pulse in between driving each digit. Not sure if that's an officially sanctioned way to do it, but it did work. It meant that while the digits were driven, the filament had zero gradient across it.
I had some trouble though, the microcontroller I was using did not have a particularly high clock frequency, and if I ran the timer at a high enough frequency for the pulses to be above audible frequencies, I did not have enough resolution to accurately control the filament power.
Of course there are ways around this, but I was just mucking around in my spare time. There would be concerns with fatiguing the filaments etc.
yeah this is possible; the filament doesn't care how it gets heated, so long as it is hot enough to emit those electrons. I like the idea of pulse heating it to prevent the gradient though, that's a great idea!
Ah, this has got me thinking about VFDs again...
For a while I have toyed with the idea of designing up some hobbyist type modules using the various inexpensive Soviet VFDs that are available. Everything on-board, only requiring a 5V power supply and data via SPI or UART. Full Arduino support etc. Target RRP of somewhere around US$20/pc.
I would peddle this through the usual channels for such items.
But I am really unsure if this would be desirable... Comparable items were quite scarce last time I looked for them.
May I ask for opinions on this matter?
Edit: Had another look. There have been some reasonably priced, fairly capable looking modules released but it appears they did not do overly well. Perhaps this ship has flown.
+kevtris Thanks for reminding me what the DC drive trick was.
Would not doubling the cathode back on itself achieve the same thing ?
Thanks for this just replaced the said capacitor and all working fine, will send the £50 replacement back when it arrives
I fixed a Siemens wireless heating controller a few weeks back and it had the same dropper capacitor and the same failure mode exactly. I ordered a replacement cap from Farnells and had the exact same problem with the footprint as well!!
Don't know why I've never watched this video before, thought I'd watched all of your earlier ones. Seems I missed a bit of a classic, too! I prefer to tug my knob off in front of the microwave, it's quicker!
*glorious*
I have a very similar oven clock at home and got annoyed by the constant buzzing sound it makes. (and that it consumes power for nothing.)
Brand: Diehl
131 47-001
Typ: 311-20 T120
Props to you for showing how to further diagnose and possibly fix such a device. I just disconnected it. (but was curious enough that I did find your video.)
The trouble is it only costs a few pounds for the part but tons for the labor . unless you are a man with your talents well done
Thanks mate.... saved me a new oven.... just repaired my Chef Finesse wall oven, a little different but fixed by changing the capacitors!
Interesting introduction...! Yeah, Creda cookers from the 90's have these. I could never understand why there was never a battery-backup for the timer. A power-cut lasting only half a second will reset the time to 0:00, and also wipe your oven Auto on/off settings. Even a large electrolytic cap would give a little buffer, but everything costs money I suppose.
Well.... I guess we all solder the same way: hold the board with three fingers and the solder with the other two. Great dexterity, Clive. :)
VFD heating filaments are mostly AC driven to avoid uneven illumination.
When for example the heating voltage is 6 volts and the driving voltage is let's say 30 volts then the voltage drop across the heating filament is significant compared to the driving voltage. 30 volts on one side of the display and only 24 volts on the other side. Thus they are AC driven to lessen this effect.
My failing AEG (Electrolux) oven clock had exactly the same fault. It's another common unit with LED display and three buttons. It would constantly re-set itself and the relay would buzz away like a mad thing. The dropper cap was kaput and replacing it brought the unit back to life. Saving £70 ish !!!
What model is your cooker?
Interesting thing to point out about these is that they use line frequency to drive the clock rather than a crystal (most do anyway)
Where I work we would say, "Cap it!" meaning replace all of the stupid things.
Cheap insurance when the work is warranted for 2 years! ;)
Thanks for the VFD explanation!
I understand that people have used the large complex ones to build audio amplifiers and such. They really do seem pretty cool.
Everytime I see how you are holdingg the things while soldering im impressed because my hand would crack if I would hold the things in this way.
+Max Power Years ago I saw that used in a TV repair shop and tried it myself, not so successfully. A little daily practice and about a week later it was if I had always been doing it like that. Nowadays it is not so easy what with lack of practice and older hands although it still beats trying to use those third hands and assorted fixtures for small items.
Mike (o\!/o)
Experiencing Technical Difficulties
Maybe I should practise a little bit because it looks kind of cool and is practical.
Max Power Just practice manipulating small items like screws and nuts, tying knots, etc. Soldering can wait until you are able enough to not have to endure burns and the like. Kind of like juggling, don't start with chainsaws.
Mike (o\!/o)
I didn't know about the reactivation trick by passing a high current through it, but the same trick is used to clean the filament that emits electrons in scanning electron microscopes ("flashing"). The vacuum gets contaminated and the filament gets coated with crap; passing a high current through it just burns it all.
so if you use a 3.3uF capacitor but instead of 250V or 400V, you use a 630V cap, it will have ticker insulation so would it last longer under regular 240V conditions than the 400V?
if I use a 630V cap on my 120V supply will it last much longer?
+chems I wouldn't increase the capacitance value, but a higher voltage rating would definitely last longer.
If you have the same issue with an oven which is similar to this you can check get your main oven to work by disconnecting the two tags on the relay which looks like the one on the left hand side when the clock is rotated around showing the back and connecting them together. This will bypass the relay which will activate when the clock is set to allow you to use your oven.
This is a safety feature to prevent the appliance from automatically powering up if you had children who like to fiddle or you had a power cut for example.
I didn't get any of the innuendos at the beginning, didn't notice anything wrong with what you said until I read the comments. I guess I'm not as dirty and/or bright as I thought.
On a completely unrelated note - Clive, could you please show us some overview of your workbench? I would love to see all those bits and pieces you pull into the shot every so often.
I've got a Beko oven and the module started doing a rapid reset. I had a quick look but didn't determine a fault, so bypassed it to use the oven. I will revisit this as it will most likely be the cap. Thanks! While I'm at it, I'll pull my knobs off. Oo-er.
I've seen that bloody Digikey advert 3 times today, on your channel, John Ward and Dave Savery. I'm already a customer, enough!
As I followed the instructions about pulling the knob off.......it quite took my mind off the broken timer and it's repair, many *anks.....sorry, I meant thanks.
the drill sound is fine the scraping was spine tingling
Filthy beginning lol
+cremationpete The subtle art of smutty double entendre.
+bigclivedotcom Subtle eh ? lol.
+Dan Harris That was nearly triple entendre.
I thought the same, so I thought "is it me or what".....? so I look in the comments to see if others commented on it hahaha lol
+Ben McKenna Clive is the best one on TH-cam doing tear downs, reviews and repairs. Julian Illet is good too! John ward does my head in, irritating little man, I just watch him to fill my hump of hate lol. Usually get a laugh with Clive though.
Learning all the UK slang from you.. got muff and knob so far, so my anatomy lesson is almost complete
There's a dictionary full of them on google, type in something like "UK English slang dictionary"
"Footery" is Scots dialect, not UK slang.
+zh84 Scotland is in the UK 😂
Pull it gently until it comes.... Right out. Oh Clive. Love your videos!
I used to work for Currys and often noticed how different appliance manufacturers used almost but not quite the same layout for controls and I do agree that the optional extra (but unused) contacts are likely there for use on different models, even different makes, even where Swedish Megaconglomerate Inc. hadn't even bought out (yet) Howthehelldotheycompeteonpricewithsuchsmallvolumesales of Wednesdbury West Midlands UK ... (before they went bust of course). Highly entertaining video as usual!
+Robert Horwat In my base-model Indesit washing machine the control panel has a PCB with all the locations for the extra knobs and buttons used on the "luxury" models with the only major difference being a different front panel and different software. (Which can be programmed from the back of the machine.)
Thanks big man- just what i needed.We bought house with oven timer kaput.Will investigate
Excellent work Clive
I'm not 100% sure how many drinks I'm supposed to take while watching this.
+zed wolf Just enough to lose control.
Overvolting the filament heats the thermionic emitter surface (a barium compound iirc) and reactivates it. CRT rejuvenators used to do this
+TheChipmunk2008 Yeah and they use to warn that there was no guarantee it would work and that it may destroy your tube still cheaper back then to give it a go. :)
+TheChipmunk2008 They act more like a vacuum tube. The grid is like the grid, the digits like a plate, and the heater like a filament. Just like a tube, the filament/heater is thoriated. The thorium lets you have electron emissions at lower heater temperature. With the filament at a lower temperature, you get a longer life and don't obscure the green digits with the heater glowing like a lightbulb. When you overdrive the heater/filament you "boil" more thorium to the surface.
"If You Want To Pull Your Knob Off In Front Of The Oven, What You Have To Do Is Gently Caress It Between Your Fingers And Then Just Pull It Gently Until It Comes" - Oh yes, Clive, I liked your technique though I'm not sure if the oven was suitably turned on by the experience.
Well, the Quick Test has shipped, it was purchased from RS Components in Sydney. Its first job will be for fixing and testing a motorised roller shutter motor. Weird thing was two vastly different prices for the same unit, but under two different SKU codes.
I worked at Invensys, I have no doubts about it being a QC problem. Rumor was they lost a contract once for sending a shipment of test failed boards to a manufacturer.
+ bigclivedotcom to release fiddly PCBs like that easier and with less risk - first warm the enclosure with a hairdryer for a few seconds to make it less prone to cracking.
Then gently lever with a screwdriver like you did, but push cut-down bamboo BBQ skewers in next your screwdriver before you withdraw it to prevent re-latching.
Trim some of the the sharp tip off the skewer with a side cutter if you need them thicker/if the thin tip is too long. Don't snap them - the splinters are very sharp.
The hairdryer technique works great for many types of thermoplatics to make them less brittle when you release clips and is especially important in cold rooms or if the kit has been stored at cold temperatures just before you need to open it.
Fixed an LED-based one for a friend a year or so back. Same problem - the 1u0 X2 dropper cap measured 620nF which was more than enough to stop the relay pulling in. Seems some brands of X2 caps are prone to this kind of failure.
Edit: And of course when used as a filter a dramatic drop in capacitance would probably go completely unnoticed.
Driving the filament with AC is better than DC, because with DC you get a voltage gradient from one end to the other, and that results in one end of the display running a little dimmer than the other.
VFD's can be used as valves (tubes) they are closer related to a valve than a crt
The construction of a VFD is akin to a triode valve - filament, grid & anode. And folk have been able to make it amplify an audio signal, albeit weakly, or to oscillate.
a "vacuum florendus err florescent display" We love you Clive!!!!!111
3 Indesit & Hotpoint Employees disliked this video
Clive - I was on Patreon.com a few minutes ago checking on my pledge-ees. Then I suddenly remembered, Clive has a Patreon account!! So I immediately became patron #470!! Do you have a new pledge goal in mind? I see the last one was reached.
Thanks again for all the great stuff, Clive!!!
Clive, do you know anything about ultrasonic wire splicing? If so how would I go about making one on the cheap :)
You may like to know that I used to be in charge of spare parts for a company that serviced white / brown goods.
Those timers are pretty standard and cost £4.95 each for the company to buy, they would charge the customer £120 to fit a new one and that was way back in 1996
If you didn't know, you can use a VFD as a preamplification tube(valve), though a crappy one. Still a fun project to do.
I'm pretty sure DC filament drive is only really an option for short VFDs as it causes a potential gradient between the filament and the grid. AFAIK the filament should be driven with AC.
+Mezgrman Yes, came here to say this... DC on the filament causes the display to vary in brightness across its length. Have seen it before in some VCRs
I used to use dentist drills to drill PC Boards. They give very clean holes of a perfect size, and you can get them for free from your dentists, if s/he is willing to put them aside for you.
Superb video as usual Clive - keep 'em coming
Clive, it would useful to shed some more light on refreshing these tubes to get better display brightness. I am sure many DIY types who refuse to buy new, simply because of age or style superseding older, perfectly good machines.
A testament to the quality of Samsung brand this mid range unit must be near 20yrs old, and though it was a trick to source the control/display module, most listings have it as discontinued or out of stock. Not cheap either. This microwave owes me nothing, but recently have been boiling stuff I only meant to reheat cause I can't see miskeyed input on the display
+Chris Leech emission may be restored by raising the filament voltage. a 33% voltage boost can rectify moderate fade, and 66% boost severe fade. The displays were designed for rugged use.
+Jeffery Rowan Thanks for that. I am going to have the unit apart to fix the door release and will do a bit of probing with a DMM to see what I have got . Mine has a few more functions and will be a little more engaging I should think. Does one need to limit the current I wonder. All I have is variable buck and boost converters running off LiPo's to get these voltages.
Dont pull your knob off in front of your oven in front of a window,the police will arrest you for indecent exposure,among other things.lol.....
That intro was pretty epic
Cheeky git. :) I love your videos, Clive, they're very interesting and tickle the imagination.
Very interesting, timer module de Dietrich oven displays oven temperature set point and actual temp, crystal display, single button, knob to press to scroll between timer modes. When we press the button it no longer scrolls... Would be interesting to have your skills.
Unbelievable with same oven , oven light stays on,when the off zero position is selected on cooking mode selector. De Dietrichs are dear and parts scandalous. Delighted to subscribe to your channel, i might learn something!
do you ever use an oscilloscope? i don't think i've ever seen you with one.. maybe some reviews on some cheapos
nice video, as usual :)
+grmlje grmone I have an Owon digital scope that I occasionally use. To save time and trying to make it visible under the lights I print off images from it for the videos.
I have a few of these displays, but it's doubtful that I will ever do anything with them. In particular, I've never run across any that were fairly generic, in the way that 7-segment LED displays can be. From what I understand they're all pretty much custom-made for the item of equipment that they're going into. And I haven't (yet?) run across any good technical info on these devices in general, or specifications on any specific devices.
I think most devices with VFD displays run AC current through the cathodes. If it was DC, then one side of the display would be brighter than the other.
+themaritimeman - Yes, I was almost shouting at the screen 'It's AC, Clive!'. I don't recall ever seeing a VFD with a DC cathode/heater.
I think the only type where it would be satisfactory would be a single-digit tube.
Whenever I repair anything with those rubber buttons with conductive studs, I clean them, and the PCB pads with meths. Most TV remotes use them and they often become inoperative after a while.
Excellent video. I have a similar timer module on my oven, where some of the segments on the display have stopped working. Consequently the display time is illegible. What would I need to do to repair the segments that don't light up please>
I had the same fault on my cooker, in fact that module is identical to the Cooke & Lewis one I repaired, I guess they are all made in the same factory,think the capacitor cost £1.32 from eBay compared to £94plus Vat B-Q quoted.
The dropper capacitor going low in value over time is a really common fault in all sorts of appliances. It's the first thing to check when the product becomes intermittent or drops dead entirely.
Its common for vfd's to have ac across the heater, in fact its better for them.
DC introduces a voltage drop across the heater wire making a brighter display at one end, this isnt as bad with ac.
Proper vfd drive chips that run off dc produce a square wave for the heater using a H bridge.
i wasnt paying attention and i heard "How to pull your knob off in an oven, just pull gently till it comes"
I have one in my cooker, but it has 4 buttons plus an encoder.
And to set the time you press cook time and end time together.
Clever little thing, I've always wondered whats inside.
First impression was partly shorted electrolytic capacitor, shunting voltage. Yet, if cap dropper fixed it, it was current issue? In either case, main input voltage or current was obvious. This because even the piezo and relay was buzzing. I've seen too many such defects as low negative supply rail as being one of the electrolytic caps being partly shorted. Anyway, as long as circuit is up and working again and relay latches as it should, its fixed.
Do you have one of those cheap ebay LCR meters? I got one for about $10 in kit form that measures ESR. It seems to work, but I don't have a decent ESR meter to test it against.
+KingNast You may be able to test it with low value resistors instead of capacitors.
Hi, there is a SMD component close to the rectifier bridge. It has marking QX 09 V. Any idea what that one is? A shottky? If so.. what is kathode and anode? Mine measures high impedance on both sides
firstly... "if you want to pull your knob off".. coupled with "you have to gently press it between your fingers".. then adding "pull it gently before it comes"... was that planned? if so rofl!It'd be great if you could tell us how to replace a thermostat on a microwave though... I've killed 3 thermostats in as many combination ovens and it's getting too expensive coz I don't know how to replace 'em.. please help! You're the man!
+motormusic1 If you search for your oven model and "thermostat" on youtube you may find there are already videos covering the specific models.
Yeh Nice one Clive but we all don't have those OLD ovens but we wish we did as these new ones are shite.
I *really* like VFDs, it's a damn shame they're few and far between as far as manufacturers go. Noritake did a promo a while back where they gave away like 100 of their new VFD modules, but barring another one of those, they tend to be *very* expensive for nice ones, since the market's been taken over by x-segment LCDs.
My Whirlpool hob has a display unit exactly like this :)
Thanks Clive! Another good 'un!.
Both informative and entertaining but the main thing I like is that it is in proper English (OK, Scottish but that's fine) not USA-ish, which grates on me unbearably, especially when solder is called "Sodder"
The innuendo i also appreciated.
I always wonder what extra buttons and jumpers do, once they are installed.
Hi, I have a question ... This module has 4 wires: on the left side (where you connected the test cables) are the Live and Neutral. On the right side above is neutral too and the other one is for? Is it DC or AC? How many V are there?
I think the two terminals on the other side are volt-free. Just the relay contacts.
Your desoldering wick is tons better than the drek I get. Need to find me some better stuff.
+Glebs Litvjaks that's actually what I've been doing, it's the only way it works. I think that's actually isn't any in the braid.
+Gadgetboy Search eBay for goot wick. It's available in several widths. This stuff is CP-3015 3mm wide (seems bigger) by 1.5m long.
+Gadgetboy I just gave up and bought a Hakko desoldering gun. I love the thing. Nothing like it when I have to desolder chips or a whole lot of parts. I once had to sit down and remove USB connectors from 200 boards. The Hakko does such a good job that when I finished the last pin 9 times out of 10 the part just drops out.
John Ridley what model?
+Gadgetboy 808. Fully self contained. It's great. It was $200 but I'd pay it again.
Was that capacitor at around 4:40 Iskra branded? I didn't know that they were still in business. It's an old Yugoslav company that used to make all kinds of electronics equipment like multimeters, oscilloscopes and soldering stations.
+Derp Herp It sure is. Well at least, the brand is.
Lovin' your videos Uncle Clive :) But for whatever reason I became curious, whilst watching this video, about just how you record/produce them. I do remember you mentioning an iPad, but how are mounting it, and are you actually viewing via the tablet's display as you work. A quick mention in next video would nice.
Thanks Clive. Always look forward to see what Uncle Clive's up to as part of my daily wind down. 😊
+MickeyDJ1 I ahve a shelf at the correct height above my bench to give the correct recording area, and the iPad sits across two pull-out slides. I have it high enough to work directly on what I'm doing, but can also check what is actually being seen too.
+bigclivedotcom Thanks for that Clive, that's satisfied my curiosity now :-D
My mother has an Amana convection range with that same sort of button layout. They would just fall out on their own after a while
Hi I've got one of these and replaced the component as you have done. I see that the relay looks a little brown and get no continuity across it, so suspect that has failed. I'll order the component and try my luck.
If the relay is discoloured then the contacts may be burned out.
Hi.....how have you powered this up on the bench?
Thanks
By any chance do you know the DC voltage out of the rectifier bridge? I am getting 0.5 volts and there is no way to know the real value of the two zener diodes test them and one is 12.3v and the other 2.3v
Thank you for this video.
How can I get someone to fix my cannon double Oven cooker. The module button not setting the time hence I can’t turn the oven on and no gas. Any recommendation or time for new cooker? Thanks
AAMOI does it roll over properly at midnight from 23:59 to 00:00 or does it display 24:00 as some do?
+Graham Langley I tried my oven last night and it did the 24.00 thing.
Where is the connection to the temperature sensor?
I though that was a oven controller.
It has the relay to start turn on the heat, but no way of detecting the temperature.
Oh, I see!
I could not stop LOL'ing in the beginning XD!.
I love VFD dispalys
Bigclive can you please explain how to fix a solar light that stays on all the time. I have cleaned it all out stays on in daylight and flattens the battery
Thanks
Im assuming under the display somewhere is a small microcontroller for the timing functions ?. Couldnt see anything visible on the board.
Yes, the control chip is under the display.
Hi Clive, I've only recently discovered your channel, and I've been binge watching while off work recovering from flu. I must be on the mend because this morning I decided to tackle something that's been bugging me for a while, an intermittent fault with our oven timer. The problem is compounded by the fact that the oven has an auto-spark, and when the timer drops out the oven goes out, and we often get a on-off-on-off dance from the cooker when the oven is switched on, and it's warmed up, meaning that the oven is unreliable. While searching online for a replacement timer, or method of bypassing it (we don't use it), I saw, there in my search results, a video thumbnail, and I exclaimed aloud "it's BigClive!", I thought if anyone would have a solution it would be you. So I watched the video, but my timer is a different model, there are similarities, but not many. Anyway, watched the vid, paused, looked at my timer, watched some more, paused again; I eventually spotted a dry solder joint - I know how to fix that! Out came the soldering iron that I've not used in nearly 40 years (I used to build guitar effects pedals when I was a teenager, but they never worked - hence the lack of use for the soldering iron!), and the solder. I let it all warm up applied heat and a little solder, and hoped that lack of practice had improved my soldering! I connected it all back up, powered up, looks good. Turned on the oven, ran it for an hour, used the alarm timer several times; hey! it works! Thank you so much for the very enjoyable channel, and getting my cooker fixed for free!