Wait a second I think the pin configuration is different.
Let me check the data sheets to confirm
Let me check the data sheets to confirm
Black on negative rail. jfet out of circuit.
DC voltage on all points.
Both terminals of D83
Both terminals of R81
All pads for Q81
DC voltage on all points.
Both terminals of D83
Both terminals of R81
All pads for Q81
D83:
Stripped side :-4.75
Other side :-5.21
R81
-22.89
-5.21
Q81
Leg 1:0.00
Leg 2:-4.75
Leg 3:4.03
Stripped side :-4.75
Other side :-5.21
R81
-22.89
-5.21
Q81
Leg 1:0.00
Leg 2:-4.75
Leg 3:4.03
Which end of D82 reads 0 ohms to the negative rail?
Remove C83 and see if the gate voltage changes.
Remove C83 and see if the gate voltage changes.
Striped side of D82 has 0 ohms to the negative rail
And if I remove C83 I get -3.90 volts on the gate
And if I remove C83 I get -3.90 volts on the gate
Install another cap there to see what the voltage goes to.
Was the positive terminal connected to the negative rail?
Was the positive terminal connected to the negative rail?
Have you given up on finding a K30A?
The diode D82 is a 5v Zener. That's limiting the gate voltage to -4.7v. That may not be enough to get a J111 to switch off. Replacing that diode with a 10vZ and installing the J111 with the correct pin configuration (don't let the leads short) may allow it to work.
If you try it and it doesn't work, post the DC voltage on all 3 terminals of the J111.
The diode D82 is a 5v Zener. That's limiting the gate voltage to -4.7v. That may not be enough to get a J111 to switch off. Replacing that diode with a 10vZ and installing the J111 with the correct pin configuration (don't let the leads short) may allow it to work.
If you try it and it doesn't work, post the DC voltage on all 3 terminals of the J111.
Can’t find a K30A
I’m am not a fan of using NTE parts but the local shop has a nte cross for the transistor
Wondering what your thoughts are on this ?
I’m am not a fan of using NTE parts but the local shop has a nte cross for the transistor
Wondering what your thoughts are on this ?
I looked through my junk boards and what are the odds I found a K30A in an old kenwood amp .
Replaced it and amp has audio .
Thanks for helping me with this repair greatly appreciate it
Replaced it and amp has audio .
Thanks for helping me with this repair greatly appreciate it
That may be useful. The 2SK30A may be available from pacparts or east coast transistor as JVC or Kenwood parts.