cleverdick
Active Member
I've just finished re-capping my PSU board, which I decided to do at the same time as fitting a newly-built RIAA preamp (the original had gone noisy on one channel).
No smoke - so that's good!
What isn't good is that the output muting relay no longer operates. (The coil measures one hundred-and-something Ohms.)
The +12V rail is present and correct, but +12R is sitting at 18.6V - although I did many years ago replace the dial lamps with blue LEDs, so that could be the cause.
So basically, I am suspecting TR725, which may have taken the opportunity to go open-circuit.
Would anyone be so kind as to confirm the type (the schematic is as clear as mud) - or at least the Vce max? I really don't want to have to remove the amp board unless I have to.
What I have noticed, on my travels through this receiver, is that the quality of soldering isn't all that. Plus, a lot of caps are right on the edge for voltage, by design.
(Pioneer scored here with the removeable base-plate.)
No smoke - so that's good!
What isn't good is that the output muting relay no longer operates. (The coil measures one hundred-and-something Ohms.)
The +12V rail is present and correct, but +12R is sitting at 18.6V - although I did many years ago replace the dial lamps with blue LEDs, so that could be the cause.
So basically, I am suspecting TR725, which may have taken the opportunity to go open-circuit.
Would anyone be so kind as to confirm the type (the schematic is as clear as mud) - or at least the Vce max? I really don't want to have to remove the amp board unless I have to.
What I have noticed, on my travels through this receiver, is that the quality of soldering isn't all that. Plus, a lot of caps are right on the edge for voltage, by design.
(Pioneer scored here with the removeable base-plate.)