Hello Folks, I'm coming back to this after a few days of prodding etc. and there has been some progress. The fault has been tracked down to the A3 input board and it points at a crack in the board or a joint. Here is the sketch: After a good clean of the switches and re-seating all boards etc. the 5370 sprung back into life with almost-in-spec performance of 102.xx ns with it's own 10 MHz. Trouble is it didn't last - after a while and triggered by sliding some switches around it went back to the 14 ns. Fiddling with the BNC's may have the same effect, i.e. there is a mechanical element to it all. Turns out that running it with the front panel removed I can make it go from 14 to 102 ns by slightly bending the A3 board, certainly while it is cold. After a while this trick doesn't work anymore, my suspicion is whatever crack/gap is causing the trouble has expanded too far to close it tight. After cool-down we're back to square one. I notice there are a few SMD components on that board, right in the middle where it would bend most - basically on the reverse side of the switches. Capacitors and resistors I expect. I wonder if it is worth going over the solder joints of all these carefully. What has stopped me so far are 2 questions: Am I the only one with this observation or has anybody come across this before? Secondly the solder on these SMD's is coated with a black substance. Clearly this could be removed somehow but it is probably there for a reason. Has anybody re-touched joints like these before? On an instrument like this it is very much a case of "proceed with care" and I'd hate to do more damage by rushing in.
On a related subject: last year there was a discussion over redesigning the input board(s) for the 5370 / 5345. Did this get off the ground? If my A3 packs up completely... Thanks in advance for any suggestions, Thomas. Date: Wed, 5 Jul 2017 11:00:35 +0100 From: "Thomas Allgeier" <th.allge...@gmail.com> To: <time-nuts@febo.com> Subject: Re: [time-nuts] 5370B Question / help needed Message-ID: <f2c3025c50df4411a8ec836c55b8e...@flintec.uk> Content-Type: text/plain; format=flowed; charset="UTF-8"; reply-type=original Thanks all for your help and suggestions - I've been off grid for the last few days. I will look into the dust/contacts issue first, and sweat up on the manual and archive posts in relation to the adjustment procedure. Then I will try to see how far this gets me and report back - watch this space as they say. I may well need the extender cards but since I am based in the UK shipment would have to be considered. Probably worth checking all other options first. Best regards, Thomas. _______________________________________________ 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.