ASTRON RS-35A Power Supply Repair
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- เผยแพร่เมื่อ 27 ก.ย. 2024
- This video addresses some issues with an Astron RS-35A power supply. Learn a quick way to see if the pass transistors are all working. Also an explanation of how linear power supplies operate.
I must apologize. I'm pretty sure I was the one who made these changes 20 years ago. In my defense I was a teenager at the time. We used whatever we had on hand, hence the the series resistors and reused TIP41. I moved the transistor to the other side in an attempt to give it a cooler location. I don't know what we were doing with R4, but I think we wanted something physically larger and higher wattage. It's nice to see a proper repair finally done!
It appears that making do with what you had worked for a good long time. Apparently the real problem at this time was the fatigued connections on the pass transistors and inadequate heat sink compound. Neither of those were your fault. Materials fatigue and corrode with heat and time.
I'm working on this type of circuitry from time to time, and in our business - this type of dialogue is just out of discussion, there's absolutely a different perspective about doing these jobs and why. (Guess what, stereotypes about electrical/idraulic workers in italy)
But yeah,
That's just a beauty to stand there, drink your coffee, and enjoy watching Mr Carlson making the essential moves and taking back stuff to roar
Are you being serious or funny? Did you really have a hand in the design of this power supply?
@@georgeowen2083 I believe the gentleman is saying that he may have owned this particular power supply at one time and made the repairs with materials and methods on hand and available to his limited resources.
pretty cool story to see your work on mr carlson's YT spot.
I was the purchasing agent for a fairly large commercial electronics, two-way radio, and towboat marine electronics sales and service company. I bought a ton of Astron power supplies, and they were fairly reliable. I've been retired for fifteen years, so my comment my no longer apply, but, the biggest failure we found was the SCR shorting out as it was not adequate. Our service manager asked me to source a higher value SCR, and the failure rate went way down. I don't remember what I bought at this point in time, but our customers were a lot happier. Thank you for your excellent video.
Simply want to say, with all sincerity, thank you for the time, care and effort that you put into this and all your videos.
You are performing a great service to the art and science.
And instructing all how to be A--N--A--L. Loosen up a little. Get your fingers a little dirty, and don't freak out about it!😆😆
I wish I found this channel before now. You are an amazing teacher, and your videos are fantastically informative. I’ve got three or four power supplies that I’ve had stuck in a corner needing fixing. With your teaching, watching your videos a few times, I now know what to like for, and how to test it.
Welcome aboard!
I really love your videos. Who would have known that you’d learn something new on a venerable linear power supply? Not only do you fix the problems, you undo other people’s ghetto hacks as well for the longevity of the system! The world truly needs more techs like you!
Enjoyed the video. Finally someone around who can talk tech in plain English and make it understandable. Being in engineering for 40 or so years and retired not many people to talk to these days and who makes it straight forward.
We had a lot of Astron power supplies just like that one. If the ac power failed, the power supply would stay off when the ac was restored, until you cycled the on/off switch. As usual, your attention to detail is superb.
For late comers, the Astron supplies are pretty much the same as far as the regulator board is concerned. The larger linear supplies have bigger transformers and filter caps. There are sometimes some additional resistors added at the factory. These are shown as "Rx" on the schematic. Also, the transistor Paul replaced is typically a TIP29A.
Have learnt all this from Paul's video and documentation and fine articles on The Repester Builder's web site in the process of reviving an RS-20A I scorched. Paul did not make the mistake I did. He went straight to the pass transistors and checked them out. I got fooled and screwed around with the regulator board. (Oh well, at least I know how it works now and am certain that the new parts I replaced are good.)
But, if you still cannot find any problems, pop in a new LM723 chip (they're socketed) and that might solve the problem.
Ah ! The old faithful LM723 - I worked on PSs way back in the early 80's with this IC... always a favorite. A pretty straighforward repair video. Well done.
I am a big fan of your no nonsense skill in logical repairs,best regards Colin.
Thanks Colin!
I have a Pyramid supply in a box in my basement that I worked on about 20 years ago. At the time someone told me they thought its problem was the transformer as Pyramid had a reputation for developing internal shorts in the windings. You have inspired me to pull it out and take another stab at it this winter.
My dad had the same one, or one very similar. It gave many years of faithful service running his ham radio at home; it was on 24/7. He gave it to me a few years ago, and although I don't regularly use it, it still works when I do. Thanks for doing a video about it.
This is a phenomenal Channel. Your integrity and attention to detail is second to none. Your ability to articulate knowledge and move logically through a repair is resulting in some very low impedance learning. Thank you.
That was a cool way to put it! I’m 65 and been a ham for 45 years and I’m learning so much from Mr. C!
The Astron power supply is done and the owner is happy and Paul is happy, but we are sad, because it's over. Thankfully I still have a back log of awesome video's to watch. So really I'm still happy. :)
Great William. Working on another video right now, (burning the candle at both ends) hopefully it will be up soon. These detailed video's take a long time to complete.
Mr Carlson's Lab I can only imagine! Thank you for all you do Mr. Carlson. BTW I really like the lighting in your lab. There is no substitute for the warm glow of incandescents. I think about that every time I watch one of your videos. I can imagine it's real cozy back there surrounded by all that fantastic gear.
William Hayden hahahha same here !!!
Wow, a 30 minute lesson that I'll always remember. I'm not an electronics tech. Just a ham operator looking for information about the Astron power supply. Fascinating lesson; thanx!
+John G
Your welcome John!
I have an RS12 that I run my security cameras on. It's been running 24/7 for the past 12 years with no problems. I also have an RS20 I keep on my workbench. Both have been 100% reliable. I think they're great.
+Glenn Martin
Thanks for your comment Glenn!
@@MrCarlsonsLab I have to 70 n 1 50 n all of them are soft about 10v got all them in 95 the 70 from aes n the 50 at a ham fest
I run the 70 together
Mr Carlson's Lab
Thank you for explaining how things work and teaching. I learned how power suplys worked with this.
Great! Thanks for your comment.
Mr. Carlson, your attention to detail is impressive, as always.
This is a very good illustration of the effectiveness of thermal paste and how important it is to use it. Those transistors were living on borrowed time.
5 years later! Still enjoys it!
Thanks
This was a great post. I own the very same Astron power supply. It’s working fine at this point but it’s 18 years old and I’m sure the thermal transfer grease has to be dry. As a precaution, I’m going to remove the transistor’s and apply new grease. I truly appreciate the safety tips regarding the capacitor and the tip about keeping a ground jumper applied during service. Thanks and continue the good work!!!
Thank You For These videos, I really appreciate them as they help me to remember how to investigate & repair.
After 35 years in the Air Force crewing jets, my electronics skills have some what disappeared in my mind. Thx Again.
Happy to help David!
Hey, I have one of those. Many years ago we had a local department store that was going out of busness and had a big sale and every thing was going, even the shelving. When I got there most all was gone however i found a car stereo desplay that already had all of the radios and speakers removed. I looked inside and found this large power supply. I asked the clerk what he would sell this desplay for. He looked at me like I had two heads and then said 15$. At the time I was into CB raido and knew that it would be great to power a moble radio and what ever "accessaries" I wanted to run. I got the thing home and took it apart and found the Astron RS-35A. I have used it for many years with no issues.
Watching this video takes me back to 1970 and my first real job at Control Data testing linear power supplies. The crowbar circuit was used on the +5v ps which had several 2N3055 pass transistors on large heat sinks. Once an assembly girl got a ceramic electrolytic in backwards and we had a nice bang and shower of debris! I moved on to testing logic cards using a GR logic tester powered by a PDP 8 but that is a story for another day.
Another very good video, one thing that was not discussed was the merit of not dropping too much voltage across the pass transistors.
Many people feel inclined to put bigger smoothing capacitors in powersupplies like this, as long as the troughs of the ripple are higher than the dropout voltage of the regulator the capacitor is big enough.
Bigger capacitors reduce the conduction angle of the rectifiers and stress the transformer more causing more temperature rise, the pass transistors and heatsink will also get hotter.
Once again a very good video with good advice!
David Lisney Thanks for your comment David!
I just purchased that power supply new - I want to modify the heat sink to your specs and "improve" on the original design. I think now my supply will last a lifetime because I know how to fix it from the transistors to the sensor - great job fun to watch video
Thanks you sir for the video. TH-cam is full of people making videos of things they have knowledge about. You are an expert and I appreciate your sharing your skills.
+Ian Butler Sorry, I meant they have no knowledge
+Ian Butler
Thanks for your kind words Ian!
I love that the vacuum tube volt meter has earned a place on the bench, working side by side with all these newer, modern technologies. It just goes to show how well electronic devices and appliances were designed and manufactured back then!!
DJT183 Every bench should have one!
Typically they have very high impedance, good for low resistance measurements or to not load things down. It's an application where the vacuum tube is very welcome.
There's a right way to repair electronics, then there's kludges. Thankfully, you know how to repair them right. Thanks for the vid, great job.
Quantum Leap Thanks!
Neat to see some familiar equipment on your bench. I worked for Transistor Devices, Inc. after they moved from Cedar Knolls, NJ to Hackettstown, NJ. I never worked in the Dynaload department but I used a bunch of different models over the three years I worked there to test other power supply equipment.
Mr Carlson, you have too much gear on that bench. Oh, I mean you need a bigger bench.
Seeing people take pride in their work never gets old. Worth every cent. I'm guessing you get a fair bit of repair the repair going on.
Very nice explanation of the power supply and the replacement of the thermoisolating stuff in order to cool down the temperature to the output transistor. Also the variable loads applied before and after the measurements . Thank you very much for your excellent demonstration. A.ballestri.suisse Switzerland
Great explanation of how a linear power supply operates, and how correct repair makes a difference vs. a jury-rig repair. Thanks for putting this video together.
Don Bower Glad you enjoyed the Video Don. Thanks for your comment!
Thanks for the nice video. I own the same power supply so I learned several tips if it ever goes bad. I think the reason the pass transistors got warm so fast before is because 1) yes, lousy thermal coupling and 2) the other 3 transistors had to make up the difference for the "bad" one. Again thanks for to great videos. Between you and TRX bench I'm always learning something new. 73's
You're talking about output transistors and mica insulators. A friend of mine used to be the sound engineer at a local disco ( way back when) He needed four really big power amps to drive the whole sound system. Two of the amps kept failing. These amps were supposed to be top of the line, thousands of $'s. come to find out, the output transistors were supposed to have mica insulators on them with thermo grease on them too. The designers removed the need for the mica wafers and just had the grease. The grease didn't quite keep everything insulated so the transistors shorted and failed. The friend finally replaced them with Crown amps that worked flawlessly.
Thank you Mr. Carlson! I have one of these power supplies and the cover is still on. The circuit looks similar to the one described in the 1988 ARRL handbook. Similar specs with crowbar protection. If the time ever comes for service this will be great reference.
oh, Mr. Carlson. I got an astron 20amp that's not working. Now I have an HF rig without a built in power supply, I searched "Astron power supply repair" and sure enough here you are! :)
Thank you.
Well, I thought i was good with repair, But you show how to go the extra mile to make sure a PS repair will last at least as long as the caps or the weakest link. you are making me improve my amateur skills , also love the weller soldering gun re wire. Duh Ive always hated the way the switch worked and never thought to re wire it- no brainer , just do it and you get the best tools in the world that work for you.
I love your videos. I found them be accident and I'm glad I did. I like your attention to detail and your willingness to do things right. Are you an electronic engineer? I'm am an electronics hobbyist and your explanations are very instructional. Keep up the great work..
+Jim McDowell
Hi Jim, Thanks for the kind words! Working on a video right now, actually. One video in the future I will do a bio, so I will keep the info until then :^) Glad your enjoying.
Great videos was trying to fix and learn about powersupplys they are very educational thanks so much.
@@MrCarlsonsLab vg
Mr. Carlson; First visit, first video...compliments on unscripted, well spoken voiceover...informative, including background and safety info. Well equipped bench, and it looks like you know what to do with all that equipment! 25A through those pass transistor sockets on the Astron is a bit much for me...I realize it would make them a lot harder to check/replace, but I'd be tempted to solder Base and Emitter leads, so socket connections couldn't fail again...RELIABILITY is key...as is use of heat sink compound! '73 KA1RPB
" Your how to " video's " AT Your Own Risk " of course are fantastic. Just wish that you showed more of the back side or inside of the PS , where the transistors plugged in by the heat sink. Great video's keep it going.
This guy is a geek man's man! Dude you are awesome! Thank you for posting these videos and educating us. You are an asset to humanity. Cheers!
Tony
Hey Mr. Carlson, do you have a part number or recommendation for the heat sink size you utilized on the pass transistor? I'm getting ready to make this upgrade to my Astron and I'm having a hell of a time finding the right heat sink. Thank you kindly, and as always thank you for what you do. 73 KN6BVX
Another great video Mr Carlson. Your thoroughness, knowledge, and communications skills make you a natural instructor. Looking forward to the nest video.
Todd Anonymous Thanks for the nice comment Todd!
Very nice detailed description of the workings of this ham power supply Paul!
Also, very good down to earth troubleshooting and repair.
Another excellent video. Love it.
Tom
***** Thanks for the nice comment Tom!
Great video as usual sir. Thank You. I had an RS-50M years ago. When almost new i actually saw a line of smoke come out of it. I cannot remember details but, after seeing your video, remember the lack of proper heat sink compound on the either side mounted pass transistors. And i also had regulator board issues as this one and i noticed some significant poor factory soldering. After cleaning all that up, i tinned the filter cap board traces and added star washers. Those filter cap screws were really loose i remember. Keep in mind i bought this thing new! After all that i ran it for many years on WSJT at close to 200 watts and had other gear hooked to it with no issues.
plantopguy5 Great story! Thanks for the post.
I was given an Astron RS 35A and told it needed a new regulator chip. I asked Yahoo group Amateur Repairs for advice and Charles AF4O recommend this video. It shows me how to open the case remove the board and where the Chip is located. Thank you for posting this video.
Forrest Plumstead Glad this video helped. Good luck with your power supply!
Great visual explaining the importance of thermal conduction. Thanks Paul
That Dynaload is a beast!
This came just at the right time, my RS-35M is down and now I know what to look for. I already ordered new transistors to replace the Chinese junk that someone installed before I bought it and the voltage regulator chip that was replaced by one I can’t find online. I just wish I could find the correct schematic for mine, Astron only has the one prior to my design and the one after… Thanks for the great explanation of the power path and what to look for.
73 WP4TGK
Hello there Paul once again. I enjoyed watching you going through this video of the power supply repair and restoration. It 's a long while since I did a complete rebuild on a heavy duty "Lab Gear" power supply that I had purchased from a supplier in Leeds. I knew the psu was faulty when I got it, so had that in mind has to be a repair project. On my first inspection I knew that I was going to be doing a complete re-build. All of the components were like out of the ark. So a shopping list was made up and the new gear purchased. Lord knows what the transformer specs where but the size of it reminded me of a ark welder unit. Plus the gauge of the secondary wires to boot. The original stud diodes where 40 Amp devises. 1 was blown. OC. I asked at the place where I had got the PSU from for as near as poss replacement for it. He had a set of 50 Amp studs that were the same size, so I said I would take those to keep a matched set. I got them for free. I got a identical heat sink to mount 4 extra TO3 power transistors on making a total of 8. By the time I was finished working on it it had Variable voltage control, auto heat sensing for fan cooling and metering for current and voltage. It was something that I enjoyed doing and was proud of my work. By the way the transistors and the stud diodes got plenty of thermal paste Hi Hi.
See you later and carry on the good work. 73 de John - G0WXU.
Just purchased an Astron RS12A power supply to power an Icom R-75 and a couple of miscellaneous radios. Now you've got me wanting to buy some thermal paste. Great video!
Steven Crawford Thanks for the comment Steven, Glad you enjoyed the video.
Excellent video! I love your clear explanations and attention to detail. I have owned a few Astron power supplies. One was the 30 amp version of this exact PS. Very interesting to see inside of one and it's layout explained. Your videos are awesome. Thanks!
your videos are so detailed and it's easy for noobs like me to understand very clearly
Enjoyed the video. Over the years, I have had several of these Astron power supplies. They do a good job. They seem to be somewhat sensitive to RF getting in and blowing out the 723. A little RF bypassing will take care of this in most cases. 73
W5KCM Thanks for the comment!
I've had an Astron RS-20A running since 1992! I'm really enjoying your videos! :)
Overlin Alaniz Thanks for your comment!
We always called the SCR across the rails crowbar protection. As in dropping a crowbar across the rails to force a fuse/breaker to blow.
I just got a Astron RS-35 from an estate/garage sale for free. It has a Grn. Lgt. above the red rocker power switch so I don't know how old it is. When i power it up, the red light on the rocker comes on. I check the output lugs on the rear with the meter, and no volts. I stumbled across this video, right out the gate. After watching your video, right at the end you said something about the "driver trans." and I was wondering if it was a regulator. Of corse, you pointe a lot more that could be wrong. but it's a place to start. Basically what i'm saying is, I used to do a little Elect. repair years ago and still do on my own stuff. If that's all that makes this thing tic, I might be able to fix it. Thank you for the good detail in the video. Like the other viewer commented, it's good to see that someone still knows or even still does, old school, basic common sence repair!
Hi Jeff. The "no Voltage out" thing could be for a number of reasons. What is the Voltage on the collectors of the pass transistors?
Wow.! I was not expecting such a prompt responce to my comment Mr. Carlson but I'll take it. I just made a reading from all four, and from ground lug to cass or collector reads 34.0 mV and from one of the phillips screws on top cover, to cass/collector reads the same. i have yet to open it up so I have not really done or allterd anything yet.
Wow! I didn't expect such a fast responce to my comment, but I'll take it. I just took a reading from the Gnd. lug to the cass/collecter, and also from a phillips screw on the top of the cabinet, to the cass/collecter and all four read 34.0mV. As of right now I have not opened it up or alterd it in any way since I got it.
Hi Jeff. From the negative post on the rear of the supply, to the case of the pass transistors, you should read the unregulated Voltage (about 20 plus Volts or so) If this Voltage isn't present, it's a fuse, faulty switch, bridge rectifier, or burned transformer.
Hello Mr. Carlson. I should have paid closer attn. to the begining of the video, where you did reference the trans. on the back as "pass trans." I finally poped the case open, and found the wire from the primary side of the transformer to the red rocker switch unpluged, and some "hokie" wiring, for somthing to do, with the not used Grn. light, and lets just leave it at that. I now have 23.0 volts at or on the board, +side of cap. and the same on the cass/ collector of the pass trans 0.541 volts from gnd. lug, to bass of pass trans. and a wopping 190.3 mV on the output lugs. You said something about the SCR ? I'm getting closer!
Another awesome video Paul! Great explanation. Looking forward to you next !
TRXBench Thanks Peter!
Nice video Mr Carlson , thanks for making it
Power Supplies are a passion for me
Very neat repair. I love seeing bodge repair jobs being rectified, very satisfying. Personally, I would have tinned all the bare copper surfaces as well to stop any potential corrosion.
Copper oxide is conductive. No reason to tin them.
The best video Channel on TH-cam. *****
I love all your information and helpful hints!
It is always a pleasure to see your videos.
You are so thorough and comprehensive.
Thank you cope to show us!
Thanks Emil!
In fact, the voltage drop at 25A is much higher, even on these screw terminals it is significant, but there is a circuit idea implemented here - when the current increases, the stabilization voltage is slightly raised to compensate for losses on the connections. Normally there would be more than 0.5V voltage drop or even more across these cable connections and screws.
Great job, health :)
Good quality power supply, expensive capacitor.
Hello, Mr Carlson, Thank you very much for the reply. I have checked the transistor and it is ok but haven't had time to do more testing now. I am so busy I am meeting myself coming and going. I will let you know what I find when I find it Lol. Have a great day. Thanks, again. Arnold.
quality person with some integrity for others people's equipment
Incredibly good video, methodically going through all the steps to permanently fix the supply and keep it running, and lots of helpful electrical tips for working on high-current applications (never knew the trick about keeping a short wire across a high-capacity cap while working on the rest of the circuit). Loving your content, keep 'em coming!
Andrew Kowalczyk Thanks for the nice comment Andrew!
I 've been following many of your video,s and they are all well done. You obviously are an engineer or a very good technician. Building circuits for correcting problems impress me a lot. 73 de VE2WNF
Glad your enjoying the video's Andre.
I was disappointed that you did not test for ripple before giving it a clean bill of health. edit: so you trust the capacitors used by astron and the low frequency means they are not being worked very hard. I did not know that caps were the ONLY thing that might cause more ripple. Thank you so much for these free videos. :)
I used to take things like microwaves and VCRs apart for a charity (ones that were broken, of course). I was always amazed by the size of the heat sinks and the transformers.
Very nice repair on the Astron. I have two Astron supplies. They weigh a few pounds but being linear are very quiet (RF quiet).
***** I agree, nice quiet linear supplies are the way to go, at least around radio gear. Thanks for the comment!
Got to love repairs that don’t require any parts just some clean up and thermal compound.
Hi Mr. Carlson,
Great vid & repair work.
I am a bit surprised about one thing.
With all of your tools, that you use your fingers on those bypass transistors is just asking for trouble; i.e. burns. I did that once and my finger hurt for 3 days and I barely touched it for just a split second.
No, I recommend today investing in an infrared - no-contact thermometer! Also useful for finding hot chips, contacts, etc.
They even have cheaper IR cameras that are even more helpful, hey - an image is with a thousand words and much quicker.
73
Nice repair, and great channel! Having the only connection to the bulk capacitor be via the threads of the steel screws that also serve at PCB mount would make me nervous. Suggested improvement to others having this supply: sandwich solder terminal lugs (Keystone Electronics p/n 913 or similar) between cap terminals and component side of PCB with solder tabs extending beyond edge of PCB, then screw down through PCB, lugs, into cap terminals, then bend solder tabs up and over top of solder-side of PCB before soldering lugs down to cap screw pads. This effectively creates pads for cap terminals on component side of PCB, connecting directly and needing less screw torque to achieve reliable connection.
Great video. Got a couple of Astrons here to repair myself.
you have some gorgeous equipment in your workshop, & your attention to detail is something I admire. I'm really pleased I discovered your channel.
Rubus Roo Thanks for the nice comment! Stop by the channel any time.
+Rubus Roo
He (Mr. Carlson) is remarkably skilled. I would have come away with a lot more from highschool if all the teachers were like him.
Same here
real pride in your work and methods. Kudos! Most workers are just hacks. I had a friend in the electronic field and he did fix all my stuff but most would come back pried apron (damaged trim and panels), scratched and dirty. Sure I bet your repairs are expensive but i also bet (and you have proven) that everything works even better than it was designed for when new. As in this instance and example. How much would it have cost for the correct component the the other people replaced.. Pennies. that is why it was putting out the wrong voltage before your work began...
Thank you for the upload!
Awesome video, I could follow along all the way this time, no homework!
Nick Moore Thanks for the comment Nick. Looking forward to that motor :^)
Learned a bit about a similar Astron power supply. Thanks
Excellent video Mr. Carlson using those God given senses of touch are nice to have.
Thanks Dr.John!
I'm such a dummy doing this kind of stuff. this computer that i'm using at the moment had an awe snap comming on every time I was doing something like this I went threw this thing and set it back to factory specks or at least I hope that is what I did. enjoy the video very much. wish me luck on mine.
the world needs more people like you, sir!
Great job long time fan of all you do for everyone 👍
Thanks Robin!
The world need,s a great guy like you .
If one needs an inexpensive high current 12 VDC dummy load, may I suggest automobile head lamps. They typically draw about 5 or 6 amps for each element. The old fashioned sealed beams are the most convenient to work with.
I suggest getting them from a junk yard. If you have a local Pull-A-Part or similar where you can remove them yourself, you can probably get them for a dollar or two a piece. Another option is if you are like me and replace lamps in pairs, you will likely have one that still works when you take it out. On the newer style bulbs you may need to get a socket, but those are readily available and inexpensive.
Mounting, wiring, and switching are let to the imagination of the builder.
Fantastic job on this video! I would have liked to have known more about the heat transfer compound that you used, and seen the application of it to the mica wafers. Also, knowing which transistor replacement you used. Keep the fine work coming.
+Skyhook Radio
Thanks for your comment! More video's on the way.
My first power supply I purchased almost 25 years ago. still going strong!
+ne2i
They are dependable!
"Dust Cooties" Technical Term....noted. Great video, thanks!
Echoing what others have said, Paul: this is a keeper. You run across these all the time at swap meets down here in SoCal and it's worthwhile having your video as a reference tutorial. Although heavy and a brute-force approach, these are easier to understand and troubleshoot than the switchers. (And, like someone said, wa-a-a-a-a-y less noisy!)
Thanks for your efforts but what I want to know is why anyone would give this a negative? Probably a couple of grumps who woke up on the wrong side of the bed.
72,
Bill, k6whp
k6whp Thanks for the nice comment Bill!
This is another great video mr Paul. Lot of things and trick I've got. Thanks 👍👍
Great video as always, nice to see someone who cares enough to do things correctly!
knunne1 Thanks! Glad your enjoying the video's!
back in 2003 I was sent to Santiago Chile to convert some RF up converters from AC to DC. When I asked for a DC supply to test them, They wheeled in a power supply built in WW2 and it dimmed all the lights when I turned it on, it was about the size of a home dish washer....thought you might enjoy that...
shair00 LOL sounds like quite the beast! Probably choke regulation, with a huge selenium rectifier. I may have owned one of those at one time :^) Dark green, louvered top cover, switchable between 6, 12, 24 Volts, Weighs as much as a Chevy truck.... so on.
Mr Carlson's Lab lol sounds like the beast although I dont remember the color and I only remember 6 and 12 volts, since I only needed 12 V i did not pay much attention. Glad i came across your channel, I have become a fan...
That's great! Glad your enjoying!
very well explained, i love you cater to us newbs to electronics.... thank you. thumbs up.
JRushPixel Thanks for the comment! Glad you enjoyed the video.
Great instructional video. Great repair! Thanks for posting this! I look forward to more of your work. BTW, I have the Astron RS-35M...great supply. Again, thanks...stay safe!
I just worked on one of these that was given to me.
The one I have has two meters in it, I thought the meter lamps were burnt out on it but after getting inside I discovered that they were never intended to be lit, so I decided to add an LED to each meter which worked out great.
I was shocked (no pun) to discover how much current was still available in the filter capacitor!!! Before I ever touched it inside I took a screw driver and shorted the lugs on top of the cap which I would not normally do like this but because it was sitting on my bench for two weeks I thought it would be drained, I was wrong!!
I can tell you now that would have hurt! I also kept a jumper wire across it the entire time I was working on it.
Note; I had read that the ones that have a meter light that the lamp life is short which is what I thought I would find here but in looking at the schematic for the one with meter lights I noticed that Astron sourced the voltage for the meter lights at the filter cap? No wonder the bulbs have a short life.
If I owned one that had the factory lights I would move the source to the output pin of the 13.8 volt lead, which is where I attached the supply for the LED's I installed.
Nice lesson Paul...
Thanks for your comment Bud!
Pristine explanation and directions! Much obliged - de N4MKX
I have only ever seen one Astron Power Supplies that failed and it was because of a nearby lightning strike and the power supply was plugged into the wall plug. It was a cheap fix and back online shortly afterwards and it is still going now 8 years or so later.Best power supply for the money.
Another superb video Mr. Carlson. Are you a teacher? If you're not you should be. Also, how many circuits to you have supplying your lab equipment?
+Thema inproblem Hi, 3 in total. Two, 240 Volt services and one 120 Volt service. Thanks for the kind words!
I've had one for abt. 50 years. it's been "on" the whole time except for a few hours to move. I did use active cooling w/three 90 mm, low rpm ("quite") fans, pointed at the rear heat sink It has been that reliable. It was used to power a 100 watt transceiver and several accessories.
I know this is an old video, but it is of great interest. My 25 year old Astron RS-35M is acting up. I'm going to look at those Transisters and freshen up the thermal paste. It's not handle the current needs of my Yaesu FT DX 3000 at 100 watts on SSB. I cleaned the binding posts, and connections inside and out, but that didn't help.
Excellent, after watching I went back and found the short. Thank you
Great! Glad this helped.