[Hammarlund] I had a working SP-600

[James A. (Andy) Moorer]

Begin at the beginning.
Check the fuses.
Measure the power supply voltages - make sure that all points in the power 
chain have voltage.
Check the 150V regulated - best place is right on the OA2 regulator. Be sure 
and check BOTH power pins - they can get opened in between.
Also check the -40V AGC bias supply.

If you have voltages everywhere, then there is an open in the signal path 
somewhere. I usually use a 'scope at this point to figure out where the 
signal stops. You can check it at the 1st RF, 2nd RF, 1st IF, and so on. 
Without a 'scope, try checking the voltage on the pins of the sockets - this 
won't tell you if it has signal, but it will tell you if, for instance, a 
plate resistor decided to go open on you. Check to make sure the voltage on 
pin 1 of the IF sections goes up and down as you move the RF gain control.

Do you have schematics? If not, go to my SP-600 page and download some.
http://www.jamminpower.com/main/sp600.jsp

Good luck.
James A. (Andy) Moorer
www.jamminpower.com



----- Original Message ----- 

>I just got a SP -600 and re-cap the power supply, the reaciver work very 
>good for an hour and then stop???!!!!! :-!