I managed to fry(?) something in my P3, while swapping it in and out to compare with a Parasound JC Jr. I mistakenly reversed the ins and outs, would this be the likely issue?
pop it open and see if anything looks toasty.
then time to check the active devices.
pictures would be very helpful.
then time to check the active devices.
pictures would be very helpful.
It doesn't have any signs of burning, I'll send some pics shortly. My uneducated guess is the active devices. I am getting some sound, RIAA seems like its ok, just no gain.
Was doing a little compararama with a Parasound and when I switched back to the P# I reversed ins and outs.
Got to head out for a bit, will check voltages when I get back, thx!
Got to head out for a bit, will check voltages when I get back, thx!
So, the RIAA is fine, it's just way down in gain, maybe 20dB, but now I really have to get going!
On the schematic shared previously, the voltages across the drain to source is one thing to check. The ones in red on this schematic are typical. 6.3Vdc on the drain and 0.08Vdc on the source. If they are shorted, even one of them, the voltages will be the same and a low voltage near 0.08Vdc. If Q5 is bad, then that will change it too. From the top with Q8 to Q5 and then Q1-4 you need voltages comparable to the ones in the schematic.
You lost both channels? If yes, check the +15 supply that it's at the proper level too.
You lost both channels? If yes, check the +15 supply that it's at the proper level too.
Notating the test points, thank you @runclesid, the bottom 2 test points, 19v & -19V, are those a source, 19v and drain, -19v? Not importanr for the task at hand, but every little bit helps 😉
Perhaps change the dipswitch to MM (and bridge the pins). Afterwards change settings back to your MC cartridge. For some reason this solved a similar issue I had after changing cartridges 🤔.
Hmm, pretty certain I tried playing around with the jumpers, thanks for the suggestion. I've already replaced it in my system and made a chart for test points so...
