Audio Systems: Kenwood amp, no sound, kenwood amp, output transistors

Question
So are output transistors easily replaced by a repairman or is it just better to get a new amp.
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Followup To
Question -
I have a KAC-818 400w kenwood mono amp, have had the same mtx 600 12" sub being powered by it for about 3 years.  Over the past year the amp would not send any power to the sub and low levels of volume.  But now it does not send anything to the sub.  The amp turns on and everything looks normal on the inside (nothing blown or broken, no electrical burning smell).  All the wiring is sound because i hooked up my friends amp to my wiring and sub. Any ideas on what is wrong
Answer -
Jon,
The problem may be due to a faulty output transistor in the amp. If anything is wrong with the output section the amp will go into protection mode to protect your speakers from damage should the output section fail. You might also want to check for a defective solder connection by lightly tapping on the amp with the stereo turned to a level that you normally listen to.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net

Answer
Jon,
I don't have a service manual for your amp so I can't tell you about the output transistors. I find that if one or two are shorted it is better to replace all the outputs due to them being weakened. On some amps you may find 4 or 5 on each side, however some amps will have 8 or more on each side ( left and right channels). On the average the cost for output transistors can be about $5-$6 each.  You will have to compare the cost of repair to the price of a new amp. I would have some one who is experienced in amp repair take a look at your amp, the problem may only be a defective solder connection.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net