Power supply board - industrial type from 1990's [solved]

gophert said:

Just because the name is not common in the US or UK, doesn't mean it is a crappy brand. They are a small company, and happy to be small, they are quite busy and profitable - even if people like Nigel want to call SAMWHA products "Crappy".

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No idea if you're correct or not? (and don't really care), the fact remains that pretty well all the electrolytics you find faulty are 'crappy' names you've never heard of.

Nigel Goodwin said:

No idea if you're correct or not? (and don't really care), the fact remains that pretty well all the electrolytics you find faulty are 'crappy' names you've never heard of.

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If we are into generalizing, do I get to associate the word "crappy" with the name, Nigel?

Stop generalizing and using the excuse, "because I've never heard of them" as some type of gold standard for what makes a good brand. You don't seem all that worldly to me and, as far as I am concerned, the PCB design is more likely to blame than the cap. And that may even be true for many other electrolytic cap failure. Just because replacing the cap makes it work, doesn't mean the cap was the root cause. Especially, don't blame the brand of the cap - that is how urban legends an mis-information starts. What happens when your employer gets blamed for a failure and it wasn't their fault? Or gets ensnared in some generalization of inept British electrical engineers?

I have no doubt you have no idea if I am correct or not. There seems to be a laziness or a preference of ignorance in your life. Ignorance is a choice, so think of it as motivational instead of insulting. Theit company history is right on their website. about us says they've been around since the 1950s. Take a look.

If that is not what you were talking about and you are not sure if the trace inductance may be the cause, look up the datasheet of the IC, it is right there in section 11.1.

Personally I don't know how those caps are performing compared to other brands.

What i DO know is their esr rating (average d value from 3 separate pcb's to be precise):
C14 : 0,229
C16 : 0,397 (at two of the pcb boards the capacitanse reads > 270 µF)
C21 : 0,294 (same rare deviation as for C16)
C3 : 0,389 (same rare deviation as for C16)
C24 and C34 : 0,012 (very good, but this caps is another type, look like a box rather than the barrel form - don't know the brand)
C26 : 0,078 (probably another brand, it's stamped "(M)" )
C28 : 0,098

That supports Nigels argument of replacing all the caps, at least the 220µF ones.

It is also very possible that C10 have a higher burden than the rest of the caps.