Excellent description of power supply repair. Like a scientist's lecture at school.

You didn't mention that after the transistors are removed the mica insulators must be cleaned and a liberal amount of thermal paste applied to both sides of the insulators. When remounting the transistors some paste should squeeze out. Wipe off the excess and you're ready to go. Most people fail to do this and it leads to another failure. Keep up the great videos. 73 KE5YTV

I remember as a kid (10-12) sneaking my Dad's Astron RS-12A from his 2-meter setup to power up a CB radio found in the curb garbage picking - many radios ended up in my room in the 80s after the boom. I was slick for so long carrying it upstairs to my room to try out another radio from a neighbor..... Then I dropped it.... same symptoms ! I sure had some explaining to do that night as he was going on a 2m net.. Love those series Astons !

I remember reading years ago that on some Astron supplies they used a regulator chip that was only rated for just barely enough current. I repaired one by installing a higher rated chip, it is still working after more than 20 years.

You have done a spectacularly excellent job with this video! It is organized, you speak clearly and slowly, you cover the process very well. AND you explain your "goofs" very well. This video is an excellent resource and teaching/learning tool! Thank you very much for your effort.

@SevenFortyOne

5 ай бұрын

Thanks for the kind words! I'm glad you liked the video.

Another interesting video Rob, don't worry about showing that you made a mistake, don't forget that someone who never makes a mistake has never made anything, 73's from England

Finally !!!! Someone makes a repair video for a astron rs 20 a repair.

@TonyLing

8 ай бұрын

Sadly, a bit of a clueless one

@SevenFortyOne

8 ай бұрын

Glad you enjoyed it!

Bought a RS20a in non workong condition, repaired it, and its been in use for at least 10yrs now.

One point to make on these Astron Linear supplies, The RS 20 is a 20 Amp max surge power, 18 AM max continuous. Since my IC-7300 can draw up to 20 amps, it over stresses the supply at max output. I've blown my bridge rectifier on my Astron, repaired it and blew a pass transistor. After that, I decided to pick up an R-35 Switching supply - and never looked back. The Linear supply is running some ancillary equipment in the shack and will serve in that capacity for many years.

Great video and thanks for keeping the oops moments in. It's nice to see that in a video now and then so that we all learn!

Excellent troubleshooting process and explained so a dummy like me can actually follow along. Now to see if I can find the problem on my 35Amp Astron PS.

Real life video! Thanks for being genuine, do not try to hide steps, we all learned with you! Good explanations, worth watching! 73 👍

Always liked the Astrons. I was not aware of the regulators as possible trouble. I like your troubleshooting breakdown, Well done!

@SevenFortyOne

9 ай бұрын

Thanks RW!

My RS50 had the 723 die along side with a resistor that smoked. Was quite the easy fix, wish I'd checked it before the damn transistors lol. This video reminded me of my adventure a few months ago.

I just repair one of them RS-20 with meter, it was bridge rectifier bad, I replaced one with 50 Amp. same time, I put 20 A fuse in DC output. I used to be repair Ham tech , many of them had bad Rectifier , bad current limiting big cement resister series with power transistor ( R102, R-102 ) . by the way , my first radio was something very similar to your Drake, mine was Trio / Kenwood , crystal controlled 10 watts FM 144MHz AG6JU

Good job Rob! I have an Astron power supply like this that has meters and powerpoles on the front of it. They are tanks.

Tip...before replacing the chip that sits in a DIP socket ...one should pull it out, look for corrosion, and reinsert. Heat and cold cycles can produce what is called chip creep which is when the chip works itself out a little. Resetting it can fix it in those cases.

@SevenFortyOne

6 ай бұрын

Great tip, thanks!

I still have that 2M rig! It was my first for 2M back in college.

I learned a different way of checking transistors. So, I consider that a win. Thsnk you for showing that. 73 de N1WKO

Thank you. I have a 40 amp supply that isn't working. Now, hopefully, I can get it up and powering.

Had the same problem with an RS-35. Never did fix it as I cam across a good deal on a switching Astron. Also good to work you from Codorus State park, PA K-1342.

Great upload.👍🕊

Great video. Thanks

Good video man.

That's fault finding for ya, sometimes it takes a misdiagnosis to get to the root of the problem.

Excellent thank you

Hi Rob, Great video. Nice you already had on hand a replacement regulator chip. Stay safe. 73 WJ3U

@SevenFortyOne

9 ай бұрын

I bought a bunch of the regulator chips the last time I fixed one of these knowing id use them eventually

I've had to do the same thing a few times with mine.

I have made mistakes before too. Should I eat 10 or 20 prunes? Well went with the 20, never again.

Why didn't you use the diode check on your meter instead of beating around the bush. I had many failed power supplies and most of them were the output transistors that failed. Case closed time saved. Yes going through as you did with voltages. But these outputs go bad all the time...

Troubleshooting is a process. Everyone has a little bit different way of doing things. You gave a great example of looking at something verifying it was good and moving on to the next logical step. Great learning video. 73

Great video!!! Robert K5TPC

Hey Rob, good video man. I have an RS-35M-AP I bought just a couple of months ago. It decided to just click repeatedly when on (no load), and the amp gauge just bounces up and down near the bottom of the scale. So far, it looks like I'm the only one in the world with this weird problem. If you have any thoughts about it, I'd love to hear them. I'm a novice and dorking around with power supplies.

@SevenFortyOne

7 ай бұрын

You might have a short in your pass transistors that is causing the protection circuit to repeatedly activate (crowbar circuit). Either that or the protection circuit itself is having an issue. Hard to say without being there myself but you could start there and see what happens

@FEPLabsRadio

7 ай бұрын

@@SevenFortyOne Roger that. I replaced all the pass transistors today, as well as the 723. No more clicking and voltage up and down, now just no power output at all. The saga continues...

My Hamfest $60 VS-50m is blowing fuses. Looks like a long fix for me. I bought mine Saturday. We will see where my Troubleshoot leads.

@jameski5oeb668

9 ай бұрын

I brought mine to a friend at work. Troubleshoot found bad rectifier circuit. Parts will arrive tomorrow and I have a couple transistors that are questionable. Also, replacing the chip, because it is not the original. I will report back. Thanks again for the video, inspiring!!

@jameski5oeb668

7 ай бұрын

Final report, I don't have any idea how the previous owner was cooking the Power Supply, but I know they showed no mercy in heat and or power consumption. This Astron had cooked the paint on the inside! It now runs like a champ again! BTW heat sync compound is the best friend to many components of this power supply.

This would lead me to the next question ❓.... Why did the IC fail? Unless the transistor or IC is known for failing... They shouldn't and my next step would be to check all the small capacitors! There's three readings you are going to need, the first one is capacity, it should read just below what's printed as it's capacity on the side of the capacitor, the second one is ESR, the lower the better ( sometimes comparing to a new one helps) and the last but not least and probably the most important is DC leakage! A cheap eBay component tester will give Vloss percentage, this reading should be as low as possible and again, compare to a new one if available! If a capacitor is leaking DC, it could be sending it to ground causing the circuit to work harder than needed, or it could be biasing up the next stage which kills transistors and ICs.... Capacitors if not leaking electrolyte will sit there and kill equipment! You will replace the burnt out component, the new replacement will tolerate it for some time but will fail again... So basically never trust a capacitor! If you value your equipment, keep a close eye on them, and always use well known brands!

@SevenFortyOne

9 ай бұрын

I didn't mention it in the video but a lightning storm came through a day or two before this power supply failed so I'm pretty sure that's what caused the problem. In fact, my radio took damage too. Thanks for the info on the caps though. I'm aware they can be problematic but opted to leave the originals in there for now.

That thumbnail title tho

@SevenFortyOne

7 ай бұрын

I know, right?

I cringed when I saw you inside of that energized power supply with your wedding ring on. If you had got current running through it you could have been injured, and your ring damaged.

@SevenFortyOne

7 ай бұрын

I cringed too...I didn't realize I hadn't taken it off until I was editing the video

very rare for a transformer to fail,its a good idea to replace the driver with a darlington ie tip 122,lowers the load on the 723 reg output!.

@SevenFortyOne

4 ай бұрын

I've had lightning take out transformers...several times in fact. it's an easy check that doesn't take much time so might as well start there just in case...

You can never learn anything if you do not make mistakes. That's the way I feel about it. 73 AE4OY WILLIE PEACOCK 🦚 EM-81UF Blackshear, Ga USA 🇺🇸