cleaning pots in sunn sorado & coliseum 880

[greg_g]

i'm totally new to amplifier maintenance/repair.  i recently acquired a coliseum 880 and a sorado, and both sound great except for scratchy pots.  how would i go about cleaning or replacing the pots for these amps--do i need to open the amp or faceplate up, or just pop the knobs off?  also, what sort of cleaner would i use, and what area of the pot would i apply it once i'm inside?  sorry about the novice questions!  perhaps a link to a step-by-step online guide would be good... or let me know if this is the sort of thing to take it to a repair shop... it seems like most folks just say "oh yeah, clean the pots a bit, easy" but i'm not sure...

thanks!

[ChrisCloutier]

Greg,  here's a few links discussing pot cleanup procedures:

http://www.hoffmanamps.com/charts/fenderservice2.htm
http://www.kbapps.com/tubecare.html

Hope that helps!

Chris

[greg_g]

yeah that's in the right direction.  my only remaining question would be whether i'd need to disassemble the amp, or can i just pop the various knobs off... "...by spraying contract cleaner through the openings in their covers" from the second page seems to indicate that just taking knobs off the way to do it, but i'd like to be sure before trying anything i'll regret.

thanks again.

[Anonymous]

looks like i'll have to take it apart to get to the pots...  no problem, since i tested it and it turns out the pots are fine on both the 880 and the sorado... sorado worked great for 2 minutes on first test with total heavenly bass tone, and then the fuse blew.  will replace fuse and then determine if it was an old fuse or a problem with a different area of the amp.  if the new fuse also blows, any suggestions on how i'd go about diagnosing the problem?

thanks again for the help

[Anonymous]

blowing fuses sucks!
First thing, make sure that your wall supply is properly grounded.
cheap testers are available at radio shack or any home improvement store.
I say to start there cuz anytime you are going to be poking around inside of a voltage amplifier, which is what you are dealing with, you want to make sure that everythng is doing what it needs to do when it needs to do it.
second, you need to learn how to discharge the power supply caps. a six pack and a good conversation should get you there from your local amp tech. I say this cuz it's better to see it done then to read about how it can be done.
third, you need to learn how to read a multimeter and how to take voltage readings off of your power supply, which is very dangerous! don't do this after said 6-pack!

cleaning the pots is easy, as long as you know what not to touch and what not to spray.

I guess there is no short answer, if this approach is to long then just take it in, if you got time and want to learn it, stasrt at step one.