I have an akai aa 1200 reciever owned since new has a problem the power cord was unplugged while powered up and playing, amp wont come back on... powers up, all lights on, can here that protecter curcut not functioning. had similer prob years ago, it was a pair of transistors. these were replaced with different than org. (no longer avaible worked fine. I replaced the same two with identacul trans. no good, maybe I should replace them all?
any ideas, love this reciever its been great has awsome power, sound really would love to see working
thanks for any help that can be provided
any ideas, love this reciever its been great has awsome power, sound really would love to see working
thanks for any help that can be provided
First of all, questions re: servicing vintage hi-fi gear really are better taken to dedicated forums, like AK.
Generally, shotgun replacement of components is highly inefficient and hence not recommended. You'll need to whip out the multimeter and perform some diagnosis. In particular, you'll need to identify spots where the power amp outputs are (easily) accessible before they go into the protection relay. Even the test points for bias adjustment will normally do, as they normally are only a few 10 mV up or down from the output.
If you don't get more than a few 10 mV to circuit ground, the power amps are fine and the fault has to be in protection and relay switching. If, however, you see multiple volts or even more on one channel and not the other, that channel has some problem and all the transistors should be checked in diode test mode when powered off at the very least.
Generally, shotgun replacement of components is highly inefficient and hence not recommended. You'll need to whip out the multimeter and perform some diagnosis. In particular, you'll need to identify spots where the power amp outputs are (easily) accessible before they go into the protection relay. Even the test points for bias adjustment will normally do, as they normally are only a few 10 mV up or down from the output.
If you don't get more than a few 10 mV to circuit ground, the power amps are fine and the fault has to be in protection and relay switching. If, however, you see multiple volts or even more on one channel and not the other, that channel has some problem and all the transistors should be checked in diode test mode when powered off at the very least.
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