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4230 DOA Amateur Needs Help

first disconnect transformer to rectifier then test again .. if lamp dims reconnect rectifier to transformer then disconnect wires from rectifier to power supply ..
if light doesn't dim disconnect the other wires from transformer ..
it doesn't have to be in that order .. just do it the easiest way for you .
 
Thanks Pete, If I disconnect the PS board from the transformer and it passes the DBT with the filter cap and the amp boards connected, can I adjust the amp at this point to see if it will set up (transformer to PS board disconnected)?
 
that looks possible ...however it is more likely
the bridge at fault or an output transistor ..
or possibly shorted lamps circuit .
 
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Ok, I disconnected the two yellow wires to the PS board from the transformer and still failed, left them disconnected and also disconnected the wires that feed the filter cap from the rectifier, in this state, it passes and has dial lights. I then reconnected the yellow wires from the transformer to the PS board, and it still passes and has dial lights. Since the power amps have been disconnected this whole time, does this indicate the filter cap or the rectifier, and if so, what is a suitable replacement part for the rectifier? Thanks Rich
 
I also get indication that the tuner is functional with deflection of and centering of the meters and a stereo light. Rich
 
rectifier and everything else apart from filter cap and main amps ok .
in other words its the filter cap or main amps at fault .. that is all what is on that circuit .
 
i do not know how it is actually wired from the filter cap to the amp boards . it might be that you can isolate left and right by removing a wire .
 
petehall347 said:
in other words its the filter cap or main amps at fault .. that is all what is on that circuit .
Click to expand...

Pete, I know the power amps may still have a problem, but I have had the red from the filter cap to the power amps disconnected this whole time, so does that point to just the filter cap for my major short for now ( I have one on order, should be here Wed.) Rich
 
if the filter cap has nothing but the rectifier connected to it then it could be the rectifier or the cap .
if the rectifier was disconnected from the cap it is the rectifier .
or a short somehow .
 
petehall347 said:
if the filter cap has nothing but the rectifier connected to it then it could be the rectifier or the cap .
Click to expand...

Pete, only the rectifier and the cap were connected and it failed, when I pulled the cap from the rectifier it passed (the rectifier is connected to the transformer, but no output from the rectifier is connected). I going to try the cap first as I was replacing it anyway, but I do not know what to order, or from whom, for the rectifier. Feel like we've made some progress, there's dial lights at the end of the tunnel :banana: Thanks Rich
 
yes .. 99.999 percent the cap .. pretty rare but is possible ...
if it were to be in backwards it would do same thing .. if original it should rule that out though .. just be sure red wires go to plus .. or if not red be sure minus goes to chassis ..
hope that made some sense ..
 
Replaced the filter cap, amps still disconnected, passed DBT, wow, it was the filter cap.... so far. Going to reconnect the power amps one at a time and see what happens! Thanks!!!! Rich
 
Connected left amp, passed DBT, connected right, got a 1/2 lit bulb and the dial lights were dimmer. Removed right power amp, passes DBT, but no audio out.
 
Since it had a bad filter cap, I am hoping recapping the left amp might help, so I have to wait for the order on Wed. Thanks for ALL the help, I surely would not have gotten this far without the great folks at AK. Back on Wed (if not earlier ;)) Rich
 
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