Noisy/Crackley External monitoring (Solved kinda)

[xmax]

This strange 6K I have been working on had loud pops when pressing the External to
monitor button and selecting different sources, after all center section caps were
replaced. After changing fets on 23,24,28 cards it was still there. What I did was
remove all the opamps on the 29 card except st1 and st2 to temporally narrow
it down. This has fixed it, so it seems one or more of those other opamps
where somehow "polluting" the whole system. when I have more time I will put
them back in one set at a time and see what the cause was.   

[chris_h]

I had the spot on same problem last month! Please look on my reply on this thread.

http://forum.sslmixed.com/index.php/topic,1214.0.html

The problem comes because of problems with wet heatshrink on card 29 (from cap to ground) it overlaps a voltage rail for the IC's and when its wet it shorts the voltage to ground.. Mine started with pops when switching sources, after a month it became intermitten with no signal, the week after it became permanently dead.

There is alot of these heatshring "condoms" in the center section card 24, 23, 25 and so on. Replace it with teflon tube!

But read my reply on the other thread that is pretty detailed!

Good Luck!
Best Regards Christian Heyman.