Fender Rocpro 1000 intermittent crackle - annoying

[jbmdisco]

Hi Guys,
Fender rocpro1000. When switched on starts to crackle which clears within seconds. Every so often (2-3 times a minute) it cracks again. Sounds like static. Has had new power caps fitted some power resistors have also been replaced and have checked over the board and sorted out some dry joints which I believe are a common problem. There is also some 'scorching' to the board at the power resistors. I have removed the resistors, checked the board for fractures and resoldered the resistors back into place. Still the same 'static' crackle. This also comes through the reverb when turned up.
It is one of those noises, very annoying, but when you try and find it, yes, it hides !!! I know I am missing something relatively basic - but everytime I try to locate it, it disappears until it's all back together. I have tried with the board in, the board out etc etc but it still eludes me.

[Jazz P Bass]

If I am not mistaken, the Reverb runs through the FX jacks.
Try a patch cord from Send To return.

If that helps, then you need to clean/ replace the Return jack.

[jbmdisco]

Thanks J P B,
As I said, probably something simple.
Will try this 1st thing tomorrow.

Must owe you quite a lot of beer by now

[Enzo]

And turn the reverb down, ball up your fist, and whack the top of the amp. Does it react? That reveals loose connections.

[jbmdisco]

After checking over previous repairs I discovered that one of the new power-caps fitted was in fact faulty. Replaced both again and the crackle has gone gone gone !!!
NOW - I run a small rehearsal room for budding musicians so with the Rocpro no longer buzzing I put it in to allow a couple of trusted guitarists to give it a good thrashing. After 20 minutes it decided to switch channels without any interaction from button pressing etc. I approached the amp with great caution - sneeking up, from behind, slowly so not to alarm it . . . . . . . then proceded to and I quote " ball up your fist, and whack the top of the amp. Does it react?" - react it did with the channel switching beginning to work then 20 minutes later same again !!! Thank you ENZO. I think a couple of new push switches are called for as this was a problem previously, to which they received a spray of servisol but with them being enclosed replacement is probably the best option.

Thanks again guys, as always, appreciated.

[52 Bill]

Thank you ENZO. I think a couple of new push switches are called for as this was a problem previously, to which they received a spray of servisol but with them being enclosed replacement is probably the best option.

Thanks again guys, as always, appreciated.

I will venture a guess that the switches are fine. That sound more like a cold solder joint in the low voltage (+16/-16) power supply. But you may be right, clean the switches again and see what happens.

[Jazz P Bass]

If you are not using the Ft Sw or do not have one plugged in, a cruddy Ft Sw jack could also do it.