[Hammarlund] SP-600 question

[James A. (Andy) Moorer]

I guess I would trace the signal from the source. This works better with a 
'scope, but a DC voltmeter will work. Start at pin 2 of V14 (the AGC 
rectifier). Stronger signals should drive this pin more and more negative. 
It either does or it doesn't do that. Then follow it through R60, R111, and 
so on. Did you check the resistances of R60, R111 and the others? I find 
these often are way out of spec.

Be sure and check C138 as well. If that is flakey, it will do just what you 
describe.

Good luck.

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


----- Original Message ----- 
> OK, for you guru's out there. I have a head scratcher. Receiver is a
> SP-600JX. The early one. Now, it was working great and now there is no
> control on the rf gain in avc position. I dug thru all the caps and
> resistors, replace tubes with no result. What happens is, if you turn it
> off, wait awhile and turn it back on, it works great in avc position. If I
> throw the switch into manual position then back to avc, volume is full
> blast, no avc action no matter where you turn the control. put it back in
> man position and it acts normal. Switch tests fine. Any one out there mite
> head me in another direction. I have been all over the avc circuit and
> subbed in new electrolytics in place of the bath tubs. I am at a stand
> still.
> Regards,
> Gary...WZ1M
>