I will check them again for piece of mind but pretty positive they are right.
I am thinking who ever tried to repair this amp before ran into the same problem and just gave up on it. I have never had an amp with this problem before it is very difficult to understand.
I understand the problem you stated but figuring out why has been very tedious.
I am thinking who ever tried to repair this amp before ran into the same problem and just gave up on it. I have never had an amp with this problem before it is very difficult to understand.
I understand the problem you stated but figuring out why has been very tedious.
OK
Using the source leg of Q110 to test Q122
C: 22.74 vdc
B: 1.700 vdc
E: 22.38 vdc
Using the source leg of Q123 to test Q121
C: 4.75 vdc
B: 2.700 vdc when testing amp makes clicking noise and pulses
E: 22.42 vdc
Q110
G: 22.43 vdc
D: 0.000 vdc
Q123
G: 22.43 vdc
D: 0.000 vdc
So using that probe configuration (black probe on sources) the readings do change.
Using the source leg of Q110 to test Q122
C: 22.74 vdc
B: 1.700 vdc
E: 22.38 vdc
Using the source leg of Q123 to test Q121
C: 4.75 vdc
B: 2.700 vdc when testing amp makes clicking noise and pulses
E: 22.42 vdc
Q110
G: 22.43 vdc
D: 0.000 vdc
Q123
G: 22.43 vdc
D: 0.000 vdc
So using that probe configuration (black probe on sources) the readings do change.
Look at the schematic diagram. The collector of Q122 is connected to the negative rail. The 0.1 ohm source resistor is also connected to the negative rail. The only thing between the negative rail (and therefore the source of the IRF540) is the 0.1 ohm resistor. If you have nearly 5v across a 0.1 ohm, 2w resistor, that resistor is either open or it's so hot that it's going to desolder itself from the board. That's one problem.
The other problem is that you still have the base of the PNP driver transistor 20v below the emitter. That would destroy the transistor. Measure the voltage on Q122 with the black probe on the emitter and the red probe on the base. What do you read?
The other problem is that you still have the base of the PNP driver transistor 20v below the emitter. That would destroy the transistor. Measure the voltage on Q122 with the black probe on the emitter and the red probe on the base. What do you read?
Q122 black probe emitter and red probe base I read: 0.222 vdc
I checked the rest in the working channels for a comparison and they read as follows:
Q222: 0.630 vdc
Q322: 0.417 vdc
Q422: 0.526 vdc
Does not seem all that much different.
I measured the 4 source resistors for that section and the voltage across them is as follows:
R136: 0.000 vdc
R149: 0.000 vdc
R166: 0.000 vdc
R180: 0.000 vdc
None of the source resistors are even warm to the touch.
I checked the rest in the working channels for a comparison and they read as follows:
Q222: 0.630 vdc
Q322: 0.417 vdc
Q422: 0.526 vdc
Does not seem all that much different.
I measured the 4 source resistors for that section and the voltage across them is as follows:
R136: 0.000 vdc
R149: 0.000 vdc
R166: 0.000 vdc
R180: 0.000 vdc
None of the source resistors are even warm to the touch.
The answer to the first question is yes.
I think on the previous page where the confusion was is I wrote the wrong transistor for the wrong set of measurements. All the measurements were correct but the Q121 and Q122 should have been switched around.
I checked again because I have been hearing clicking and louds pops on the board. I dont know whats going on with this amp is acting very wierd. After hearing the noises I re-checked the Q122 and Q121 readings. The clicking noises have stopped, I think maybe something went out on me.
Q122 black probe on source of Q110 I read as follows:
C: 3.155 vdc hear a loud click and amp draws 25 amps of current
B: 3.155 vdc hear a loud click and amp draws 25 amps of current
E: 22.42 vdc
Q121 black probe on source of Q123 I read as follows:
C: 22.74 vdc
B: 0.554 vdc
E: 22.38 vdc
I dont get this amp. I noticed some of the outputs, the four in this section are getting warm to the touch.
I dont know it fell apart while trying to remove it. I replaced it and retested with same result. I removed the 4 outputs in the 2 series section as they were getting warm.
Repowered the amp to do some testing and it drew 30 amps current and the other 4 in the 1 series section burned my fingers they were so hot.
I removed all the outputs from the 1 and 2 series channels. Is there any testing I can do with the outputs out or do they have to be in?
Why does the gate to source read OL on Q110 and Q123 but all the rest read 13.96 M ohms?
Repowered the amp to do some testing and it drew 30 amps current and the other 4 in the 1 series section burned my fingers they were so hot.
I removed all the outputs from the 1 and 2 series channels. Is there any testing I can do with the outputs out or do they have to be in?
Why does the gate to source read OL on Q110 and Q123 but all the rest read 13.96 M ohms?
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