HELP!! SA800 Pro amp not working

[shaggydoo]

hi all
I have a t&m performance sa800 pro amp id like to fix as I didn't have any problems with the last one I had. ive bought quite a few none working amps this was the first to turn up.

I connected it up and got nothing from channel B. on channel A they is some sound but very distorted even at the lowest setting.

I opened the amp up seen on channel A somebody has taken 5 of the pairs of the transistors out (2sa1943 & 2sc5200)

none was taken off channel B so I swopped 1 of the boards over inside but the amp is still the same.

would be very greatful if I could get some help as the best was to move forward and some advice on testing the amp please. unfortunately I only have a dmm (Edison DM383)

any help will be greatly apriciated
thanks in advance
simon

 

[smartx21]

Simon, I would never turn a dead amp on, before doing a deep search for bad or missing parts. Also I would have the power supply checked before that as well. But you need to test every transistor on the board, and replace each bad one for similar parts. Also check fuses, diodes, resistors and even capacitors. A picture and schematics will help us support you in this quest.
All the best!

 

[smartx21]

BTW, is it this one?
http://www.stageaccompany.com/support/vintage/electronics/sa800-1600.pdf

 

[shaggydoo]

no its not that one. ill try take some pics and workout how to put them on here. thanks for reply

 

[shaggydoo]

I cant get the pics on here ive tried everything it says your ment to do but nowts happening! its really frustrating could someone advise me please

 

[shaggydoo]

amp pics hope this helps

 

[amptech]

Hello, quick look at the inside view on middle Photo Shows some o/p devices missing..possible to this is, they may of gone short So powering this unit up you would get uneven Balanced o/p circuit.

 

[amptech]

Just One thing and Not to over cloud things on tech speak, such as dif pairs, vas stage etc...working on Power amps takes understanding whats going on in there..