Hello Michau, >> Well, there are a few things that would be good to know. >> - What are they using as the primary switching transistor? > > There is someting that looks ike a big transistor which reads > "BUV47A". > >> - What are the ICs on the vertical board? > > They are a 4006 and a LM339N. The 4006 can be a UAA4006 (see http://www.datasheetarchive.com/UAA4006-datasheet.html). The typical application example (http://pdf.datasheetarchive.com/datasheetsmain/Datasheets-30/DSA-593994.pdf) shows a BUV45 for the switsching transistor. So i think this can by your power supply! Can you check it? >> Also, all capacitors with an 'ROE' logo should be regarded as suspect >> and at least checked if not replaced. They tend to mutate into a >> short circuit internally. I see a few of them on the righthand side. > > There are some labeled "ROE" and some labeled "FRAKO". I tested with > an ohmometer without unsoldering them, and it indicated a short > circuit everywhere but I am not sure whether is is from a bad > capacitor, or from some other circuitry in the PSU? You can't measure the resistance without unsoldering. The next problem is, all these capacitors have a lower capacity over the time. When this value is too low, the PSU don't work. So i would change all electrolyte capacitors. But you need low-ESR types on the secondary side! Martin Message was sent through the cbm-hackers mailing listReceived on 2015-01-09 17:00:03
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