Magnus, The service note is attached.
Orin. On Sun, Dec 28, 2014 at 8:04 AM, Magnus Danielson < mag...@rubidium.dyndns.org> wrote: > We had that issue with the 5335A at work, and replacing the relay did the > trick. > > 5335A is still the counter which is easiest to use, even if it doesn't > have stellar performance, but usually that is not needed. > > Where did you find the Service Note? > > Cheers, > Magnus > > > On 12/28/2014 06:06 AM, Orin Eman wrote: > >> While evaluating my LTE Lite and testing my buffer board, my 5335A started >> acting goofy - random hangs/crashes etc.. >> >> This morning, the fan came on, but no display. >> >> To make a long story short, the problem was exactly as described in >> Service >> Note 5335A-26B. I found evidence of overheating on the power supply >> relay. The 5V (and 3V) supply was down. During investigating the fault, >> I >> disturbed the power supply relay and reseated it. The instrument worked >> again. Further investigation revealed a cold looking solder joint on the >> relay socket and spread contacts on the relay socket. About 1V was >> dropped >> across the relay socket and the relay itself. I resoldered the socket and >> 'persuaded' the contact with a small screwdriver. All now seems to be >> back >> to normal. >> >> FWIW, do not believe the part number on the relay. It is really a 6PST NO >> beastie for which I have not yet found a replacement. >> >> The above mentioned service note adds a second pair of contacts for the 5V >> supply after replacing the 120V fan with a 24V fan fed from the power >> switch. This uses the relay contacts that used to be used to drive the >> 120V fan. Ideally, you replace the relay and its socket as well, but good >> luck finding the relay. My unit has the 24V fan, but I have yet to do the >> rewiring for the second pair of contacts, so I suspect the fix might not >> last. Still, it's 22 years since the date on the service note, so I might >> have a few years. >> >> So, if your 5335A fan comes on, but no display, check the 5V supply first >> and if it's down, suspect the power supply relay/socket. >> >> Orin. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> >> _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. >
Service Note 5335A-26B.pdf
Description: Adobe PDF document
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