So have a 1000/1 had a bad rectifier. Up and running, idles fine, low voltage good everywhere, switching drive looks good on outputs but no audio is reaching outputs.
Tracing out preamp now. Any advice would be welcome.
Tracing out preamp now. Any advice would be welcome.
With a speaker and signal source connected, did you operate all pots and switches in all combinations to see if any audio/static/noise ever played through?
Have you lifted and reset the preamp board?
If you push on various parts of the two boards, does that make any difference?
If you push on various parts of the two boards, does that make any difference?
What is the resistance between legs 1 and 2?
Go back and check the pots and switches with signal and speaker with the transistor out.
Go back and check the pots and switches with signal and speaker with the transistor out.
22 ohms. Its a J fet? J111
OK, audio is fine now. Polarity switch was not passing. Everything is cleaned and working now.
What to replace the J111 with?
OK, audio is fine now. Polarity switch was not passing. Everything is cleaned and working now.
What to replace the J111 with?
22 ohms doesn't indicate that it's defective. JFETs read low resistance D-S with no gate voltage.
If it is actually defective, replace with the same.
If it is actually defective, replace with the same.
All working.
However, there is a pop on speaker when amp shuts down.
I know output drive remains for 15 seconds. Is there a muting that engages prior to rail going away?
However, there is a pop on speaker when amp shuts down.
I know output drive remains for 15 seconds. Is there a muting that engages prior to rail going away?
Did you confirm that the muting transistor (j111) was installed correctly? The control voltage should be on leg 3, not leg 1.
It is in the proper orientation.
I did check it with my MK-328 which does check Jfets and it checked as 2 diodes. It did not id it as a jfet. Don't always trust the MK-328 though.
I did check it with my MK-328 which does check Jfets and it checked as 2 diodes. It did not id it as a jfet. Don't always trust the MK-328 though.