4001 stuttering

[ekwat]

Anyone know why my 4001 would be stuttering, cracking and generally breaking up? It's worse on some channels than others and I used to think it was a bad feed but I have another that works fine from same feed. Could the tuners be fooked, or ithe caps? ( Every time something goes wrong with these boxes someone says change the caps ) even though they look fine with no bulging or leaking?
Any advice is appreciated.

 

[Spectre]

It could be the ceramic decoupling caps on the underside of the board as well.

I'd suspect the ones underneath the AVIA chips first.

Ceramic caps generally fail by going short, if they don't catastrophically fail they get worse as they warm up.

 

[ekwat]

I'll take a look tomorrow see what's going on underneath. Thanks