"Maciej W. Rozycki" wrote: >On Sat, 5 Feb 2022, Peter Coghlan via cctalk wrote: > > > > This PSU seems to have been used across various Cisco devices and I had > > > one fail several years ago in a WS-C1202 Ethernet/FDDI switch, also > > > having > > > suffered from leaking caps. Back then RS still had it in stock at a > > > hefty > > > price of £489.60: <https://uk.rs-online.com/web/p/products/8338173/>, so > > > I > > > chose to recap the failed one and thanfully it has continued working ever > > > since. You may try to enquire with the manufacturer. > > > > > > Good luck with bringing yours back to life! > > > > > > > Thanks Maciej. I'll be surprised if the manufacturer has records of > > what they used for the chopper in power supplies 30 years ago - who > > knows if their design has changed between then and now. I'll be even > > more suprised if they will talk to me about it but I guess it's worth > > a try. > > I've checked their web site and they continue to offer a MAP80-4000G, > which I suppose is just a minor update from the original, and is visually > the same, as it seems from the datasheet dated 2021. So I'm fairly sure > they have all the data. Those discrete semiconductor components do not > change much, I was able to order exact replacements for another faulty > device from 1990s a few years ago. > > They may offer you a paid repair or replacement service or if you're kind > enough and they are reasonable, they may identify the single part for you. > > NB Mouser has the MAP80-4000G in stock actually, so if all else fails and > you are determined to get the IGS running, you can pick a brand new one: > <https://www.mouser.co.uk/ProductDetail/784-MAP80-4000G>. >
Thanks again Maciej. I've bit the bullet and unsoldered most of the electrolytic capacitors and other components that seem to be in trouble. When I got the chopper transistor out, I found that if I hold it at exactly the right angle to the light, I can see that there are faint markings on it after all and it turns out to be an IRFPE50 HEXFET. I was wrong about the cracked RIFAs not being mains filters too, they are actually across L-E and N-E and they seem to have between a few hundred kOhms and a few MOhms leakage too. The driver transistor looks like it might be ok. Regards, Peter Coghlan. > Good luck! > > Maciej
