[time-nuts] Repair of 5370B input channels

[John Ackermann N8UR]

Jim Miller said the following on 06/08/2006 07:33 PM:
> Hi,
> 
> I recently acquired two 5370B counters with bad input channels.  One  
> has a bad start channel,
> the other a bad stop channel.  I have traced the problem to the input  
> board A3, which is the board directly behind the BNC connectors on  
> the front panel.
> 
> Has anyone had any luck repairing the input circuitry in these  
> units?  Is there a common failure mode that occurs when signal levels  
> are exceeded?

Jim, I'm not certain but I think that there are some magic parts on the
input board that are pretty much impossible to obtain -- and the inputs
are relatively fragile and won't survive excess voltages.  Sorry for the
bad news; you might be able to merge the two blown boards into one
working one, though.  I have the service manual if you want to borrow it.

John