On 1 January 2015 at 17:03, Andy Bardagjy <[email protected]> wrote: > Sounds like the GPS receiver is hosed. I think there are two different > receivers used in the 58503a, unfortunately I'm away from my lab, otherwise I > could check mine. It is a standard part, and may be available on the surplus > market. > > Before replacing, I'd check the usual suspects, power supply health (look for > failed electrolytics) and re-seat the gps board to board connector. > > Happy to measure things on my 58503a.
The fact it originally failed with errors indicting the GPS receiver was not ok (nt Power- OK, OCXO- OK, EFC-OK GPS RCV-err. I, but later he can't communicate with the 58503A over RS-232, to me indicates the problem is not likely to be the just (if at all) the GPS receiver. As you say, power supply is a possible problem. I have a 58503A here that has a problem. Sometimes when power is first applied, the "Alarm" light stays on, and the log show power supply voltage errors. Yesterday I must have switched the thing on/off about 30 times before I managed to get the "Alarm" light to stay on. At the time I had a handheld DVM connected to the +15 V rail with the "peak hold" mode enabled. At least according to the handheld DVM, the +15 V rail was normal, so either the transient is too short for my handheld DVM to see, or the 85050A is reporting data voltage data incorrectly. Both are fairly like I suspect. I noticed a *very* slight bulge at the top of on a 100 uF, 400 V capacitor on the switch mode power supply. For various reasons, I am not going to change that cap now, but obviously a failed cap could cause this sort of problem. Dave _______________________________________________ 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.
