[time-nuts] If your 5335A is acting goofy or dead...
orin.eman at gmail.com
Tue Dec 30 12:15:13 EST 2014
The service note is attached.
On Sun, Dec 28, 2014 at 8:04 AM, Magnus Danielson <
magnus at rubidium.dyndns.org> wrote:
> We had that issue with the 5335A at work, and replacing the relay did the
> 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?
> 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
>> Note 5335A-26B. I found evidence of overheating on the power supply
>> relay. The 5V (and 3V) supply was down. During investigating the fault,
>> 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
>> 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
>> 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.
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