Hello im sorry but not speak english a litle, im need picture of power amplifier crate model spa-1200 made in u.s.a.fabricated for slm electronics,1400 ferguson ave. st louis mo. 63133 and not found picture or fhoto in google and others pages, please helpme i need the picture tanks god bless you. bye

https://www.google.com/search?q=crate+spa400+schematic

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Question edited for clarity (with a guess at model).
Question moved from Television and Video.

If you want to check inside it, look for damaged components or blown or bulging capacitors. The best solution is to take it to a local electronics or audio store for repair.

https://www.google.com/search?q=crate+yellow+amplifier+no+sound

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SLM sold the company years ago to Loud audio. Its only supported online now. Loudaudio.com

Clean vents may be shutting. Down because of. Thermal

depends

Usally a ground loop isolator will fix that problem. It plugs into the RCA's between the radio and the amp.

Try to reground the amp in a different spot.

Or run a refrence ground from the deck to the amp next to the remote turn on wire. (still keep your main amp ground hooked up)

DO NOT run your power wire next to the RCA's, that will induce a field which in turn can cause that buzzing sound.

http://products.bose.com/pdf/customer_service/owners/og_ls_vclass.pdf

Good Luck!

sounds like you power supplies (mosfets) are bad

you might need to see what your volts are if there 14.4 at the amp thats good but see what they drop to ....

Sometimes an amplifier's preamp can't handle certain signals/frequencies at a high gain, so they cut out. Bass guitars are especially prone to giving such a strong signal.
I bought an older, nonworking bass amp recently and fixed it just to find it had the same problem. Best solution is to put a low ohm resistor at the amps input, but if you turn your guitar down to half volume it'll have the same effect: should prevent it from cutting out.