TECH GURU's out there, how to clean Circuit Board?

well, 1st unplug from the wall. ensure that the power supply caps are discharged before you stick your hand inside the chassis.
best would be if you can disassemble the portion of the amp that needs cleaning. this way you can conveniently handle the PCB outside the chassis.
use alcohol - the 90% type you can get at a drug store - to clean the mess.
Chemtronix makes a can of a fluid called "Flux-Off" that is water soluble. You can spray this on the PCB & then remove the residue w/ alcohol.
Hooe that this helps.

Seandtaylor99,

perhaps you did not read Rapogee's original post correctly. I cut & pasted here: "Older Rotel amp, there some greasy stuff and cat hair all over the internal board, very dirty and grimy....."

greasy stuff will not be blasted off by compressed air. In fact, if the greasy stuff is at all mobile, compressed air will splatter it farther & wider creating an even bigger issue in other parts of the amp (that perhaps do not have issues so far)!

OTOH, Seandtaylor99, does bring up a good issue that the 90% alcohol does have 10% water in it. I can tell you that I have cleaned PCBs with this 90% alcohol before BUT..........I did use a hair-dryer to dry the PCB + I let the PCB air dry for atleast 24 hrs before I switched on the circuit.
Good catch Seandtaylor99! Otherwise, I would not have mentioned my hair-dryer routine! ;-)

Rapogee: the Chemtronix Flux-Off will not harm the PCB. I've used that chemical routinely to remove sticky/guey flux paste & fluid from PCBs. No harm has ever been done to the PCB.
Like I said above the alcohol will not harm the PCB either. However, make doubly sure that you dry the PCB (make that water evaporate) before you plug the PCB back into the Rotel amp.

Seandtaylor99,
my good man, I did read Rapogee's original post very well. Yes, I noted that it "works perfectly but I believe its not a healthy thing".
even if the gear is working perfectly, electronics & "some greasy stuff and cat hair all over the internal board" are 2 things that do not go together! a dirty PCB is a disaster waiting to happen especially in a power amp (a high gain & large signal piece of gear). it should/must be cleaned up otherwise failure over the longer term is almost certain.
It looks like we disagree. OK, so be it!

>> 03-09-06: Rapogee
>> Thank you very much guys, very helpful.
>> Just to clarify, I tried the micro vacum and compressed
>> air and that did not work. There is hair and dirt still
>> sticking,

Rapogee, thanks for the feedback! I didn't think that compressed air would work on the greasy grime.

The MG Chemicals Flux Remover looks very much like the Chemtronix stuff that I recommended. FYI: the Chemtronix stuff is an industrial product that is used in my engineering lab here where we populate PCBs to test out some of our ICs that go into cellphones. My recommendation was *not* a butt-pull - we use this stuff nearly daily to get guey stuff off our PCBs esp things like flux paste/fluid. Like the pix on MG Chemicals webpage, the Chemtronix can comes w/ that red colour straw nozzle that allows us to point the fluid more-or-less exactly where the guey stuff is. We have *not* ruined any PCBs so far & we have been in operation for over 10 years!

I was thinking of this last eveing & here is another idea: how about using "Goo-Gone"? I have used it to remove several sticky things (like stickers on CD jewel cases, airport security stickers on suitcases) but never on a PCB so far. This Goo-Gone is citrus-based (atleast the one that I have) & it does a great job of removing guey stuff. I've used some alcohol post Goo-Gone to get do the final clean-up. In your case, use a hair-dryer to dry the PCB thoroughly + let it air dry for 24 hrs before turning on the amp.
IMHO, this should really do the job for you. FWIW.

thanks again on the feedback, Rapogee. looks like a job well done by yourself!