DC-508 repair advice

radioconnection@...
 

Hello to the group--not exactly a Scope problem, but I was given a TM-503 that was full of plug ins. There is a 508 counter that does have the
preselector daughter board installed.

It is not working. When using the presecaler the input level led shows it is seeing a signal from my HP-8640 signal generator. The gate lamp
is flashing. The display leds are blanked until the counter sees a signal, and then the LEDs only show zeros, but no counts. On the direct
input the counter also does not count. Gate lamp is flashing. The PLL light goes out when I apply a 1 kHz signal. I am guessing there is
something wrong with the gate since the input and timebase seem to be working?

I do not have extender boards and I am very unfamiliar with this counter. I did download a PDF file of the manual, but it is rather cumbersome
to use on a computer. Any suggestions where to start?

Also, I've read there is an Option 7 that was intended to use the DC508 with a TR-503? What exactly does that show? The center scan
or the exact count as the SA is being swept? The 503 does have an aux. RF out that could be fed to the DC-508, will that do the same
function?

Pete

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