Hi,
Thanks for the details..... hmmmm........ food for thought there........
There is a desk in the workshop at present. It has been re-capped, so too late to look at the physical caps, however, there is nothing noted in the project file about bad/swollen caps. I have also asked my colleague who did the re-capping and he confirmed that there was nothing suspicious to report.
Here's the interesting follow-on.... we also have a batch of modules that are booked to the next refurbishment project which has not been started yet, so everything is as it was delivered to the workshop.
C13 & C14 on a random selection of 82E10 cards on 6 modules are all OK. The soldering is, I believe, the original factory soldering (or someone is way better at soldering and board cleaning than I am or anyone I work with
). The test date of the cards is 6/91.
However....... a couple of the random modules have cap-swell on the 82E294 Group Amp cards.
Consistently the caps are C4, C23, C15. All are output caps (C23 is one side of the balanced output). All are 220uF 6.3V non polar. Soldering is original. Test date is 6/91. The circuit topology does NOT have the two series caps with a pull-up resistor to +V, so voltage bias to a rail is not an issue.
The plot thickens......
