exxos's Atari, Amiga & retro forum

One of the channels I frequent on YouTube is CuriousMarc.

It's a great channel with a lot of content across a number of subjects, and talks a lot about electronics and troubleshooting, something I am learning, and has helped me a lot.

There are a few videos on repairing more modern tech though, and there are some that go into replacing capacitors that have failed.

I particularly like this video, https://www.youtube.com/watch?v=Z4Kp8BDMzHY, because at about 9:30, he pulls apart a bad cap and a good cap, and the difference between the two is night and day.

So, in case you don't believe capacitors fail, have a look at this video and think about what might be going on, unseen, in your caps. It may surprise you.

Amazing how long it is rolled out. Interesting to see the insides.

I like the non electrolytic capacitors. But sometimes you have to use the electrolytic ones but low esr and 105c and 125c if you can get them. And the paper rifa ones should be replaced often or replaced with polypropylene ones cause they stink when the burn. And the smell is very hard to get out

Tom

Yes, CuriousMarc's videos are always worthy to be watched. He repairs really rare stuff sometimes, such as the Apollo Guidance Computer ("Apollo" as in Apollo moon mission). Plus, I very much like how his repair videos focus on actually diagnosing the fault instead of just randomly swapping components. He even says so himself in a video where he repairs a power supply:

There were of course the predictable comments that I should just (a) replace all the caps and (b) swap it for a new supply. [...] I'm not going to do either of those two. The first one, which is just speculative part swapping, would only repair the supply by just pure stroke of luck. Now, you might have lucked out once or twice, or you might not have the equipment of knowledge to do any better, but you should still try. Debugs based on speculation won't get you very far. On the other hand, if you are capable of understanding what is happening, you will be able to repair every circuit every time and won't be tossing away perfectly good components.

Also Ken Shirriff regularly appears in CuriousMarc's videos. Ken does amazing chip-level reverse-engineering in his blog: http://www.righto.com.

well if I had the money I would buy a equipment chiller and inferred camera. I've seen them used in industry and universities. With amazing results.

Tom

Tomswork wrote: 12 Aug 2020 00:40 I like the non electrolytic capacitors. But sometimes you have to use the electrolytic ones but low esr and 105c and 125c if you can get them. And the paper rifa ones should be replaced often or replaced with polypropylene ones cause they stink when the burn. And the smell is very hard to get out

Tom

Yep. RIFAs suck, two in the Mac Classic I'm working on had cracked and split so needed to be replaced.

czietz wrote: 12 Aug 2020 07:18 Yes, CuriousMarc's videos are always worthy to be watched. He repairs really rare stuff sometimes, such as the Apollo Guidance Computer ("Apollo" as in Apollo moon mission). Plus, I very much like how his repair videos focus on actually diagnosing the fault instead of just randomly swapping components. He even says so himself in a video where he repairs a power supply:

There were of course the predictable comments that I should just (a) replace all the caps and (b) swap it for a new supply. [...] I'm not going to do either of those two. The first one, which is just speculative part swapping, would only repair the supply by just pure stroke of luck. Now, you might have lucked out once or twice, or you might not have the equipment of knowledge to do any better, but you should still try. Debugs based on speculation won't get you very far. On the other hand, if you are capable of understanding what is happening, you will be able to repair every circuit every time and won't be tossing away perfectly good components.

Also Ken Shirriff regularly appears in CuriousMarc's videos. Ken does amazing chip-level reverse-engineering in his blog: http://www.righto.com.

Absolutely, I love the way he will go to the lengths of even drawing his own schematics if there are none available, and you're right, going into the actual diagnosis is just great, and even if you don't understand to begin with, you can start to understand the more you do.

What frustrates me no end is the lack of repairability in modern kit, it's designed to be thrown away when it breaks. I very much like to fix things these days, whatever they are. Even if you don't succeed at least you tried.

Agree about Ken, his reverse engineering is just brilliant!

rubber_jonnie wrote: 12 Aug 2020 09:23 Yep. RIFAs suck, two in the Mac Classic I'm working on had cracked and split so needed to be replaced.

They don't have the nickname of "delayed smoke generation devices" for nothing.

I'm really surprised that they're still made and sold. I guess they might just be cheaper and last longer than the manufacturer's warranty.

I wonder if he could reverse engineer a chip for me... It's one of the custom VLSI jobbies in a Sun 3/80 (Decode1) which has developed a fault on my machine. ;-)

stephen_usher wrote: 12 Aug 2020 10:07

rubber_jonnie wrote: 12 Aug 2020 09:23 Yep. RIFAs suck, two in the Mac Classic I'm working on had cracked and split so needed to be replaced.

They don't have the nickname of "delayed smoke generation devices" for nothing.

I'm really surprised that they're still made and sold. I guess they might just be cheaper and last longer than the manufacturer's warranty.

Oddly, I couldn't get the same exact cap as a replacement, only the one it replaced, but for a machine that won't get a lot of use (If I ever get it running again!) they'll do the trick.