In a message dated 22/09/2009 11:16:03 GMT Daylight Time, [email protected] writes:
The filter is an FN372 2A unit. This is a common failure. It's due to the particular type of epoxy cased, self-healing capacitor used in the filter. The case encapsulation cracks and if the unit is left in storage damp gets in. The self healing is by the metal coating that forms the capacitor plates vaporising when the insulation breaks down. Evenventually this forms a sort of chain reaction and the whole thing goes up in acrid smoke. It's not related to any MIL spec. The capacitors are used in some Farnell powersupplies and are a common failure there as well. Equipment that is in regular use seems to be OK, leave it in the garage for a year and you may have trouble. The problem with the FN372 is that it's a snap fit and has the voltage selector built in. There is no direct fit alternative that I know of. New FN372's (with better capacitors) are available from RS for under £30. --------- Hi Robert Thanks for the information. I wasn't thinking it was anything to to do with a MIL spec, pretty sure these are standard Solartron spec anyway, but just commented on it being ex-mil as many have come on to the UK market as military surplus. However, your comments on storage suggest that origin might be more relevant than I appreciated. My three units have all been kept warm and dry here but there's no telling how they might have been stored in the run up to, and following, disposal, I've seen plenty of previous examples of ex-mil kit that has suffered from poor storage conditions. When I have more time I will see if I can rebuild one of the blown filters, although these are quite nice meters I'm still reluctant to spend around £90 on replacement mains connectors. I agree it's the snap in issue that makes it much more awkward but I'm considering the possibility of fitting an adaptor plate to accomodate a screw fixing connector/filter, or even an alternative snap in. Doing away with the voltage selection option is another possibility that might generate more space to work in. Regards Nigel GM8PZR _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
