This amp is identical to Memphis 16 ST 1000D.
The problem is on the power supply module, the two 1266 driver transistors along with sot 23 diodes have melted, damaging the board.
I managed to reconstruct the area, but there is no triangle wave on pin 5. Ct is new (1nf) and Rt reads ok (36K)
Even tried to change the 494.
Here are the readings of 494
Pin 1 0
Pin 2 5
Pin 3 0.07
Pin 4 0.59
Pin 5 0.45
Pin 6 3.71
Pin 7 0
Pin 8 14.2
Pin 9 0.28
Pin 10 0.28
Pin 11 14.2
Pin 12 14.2
Pin 13 5
Pin 14 5
Pin 15 5
Pin 16 0
I also need to confirm a factory added capacitor 22/25V between pin 4 and ground.
The problem is on the power supply module, the two 1266 driver transistors along with sot 23 diodes have melted, damaging the board.
I managed to reconstruct the area, but there is no triangle wave on pin 5. Ct is new (1nf) and Rt reads ok (36K)
Even tried to change the 494.
Here are the readings of 494
Pin 1 0
Pin 2 5
Pin 3 0.07
Pin 4 0.59
Pin 5 0.45
Pin 6 3.71
Pin 7 0
Pin 8 14.2
Pin 9 0.28
Pin 10 0.28
Pin 11 14.2
Pin 12 14.2
Pin 13 5
Pin 14 5
Pin 15 5
Pin 16 0
I also need to confirm a factory added capacitor 22/25V between pin 4 and ground.
In all of the photos I have, there is a 10uf cap between pins 1 and 4.
Is there any carbonized fiberglass in the area that could be conductive and causing a problem?
Is there any carbonized fiberglass in the area that could be conductive and causing a problem?
Generally, you have to cut away all conductive material and hardwire the components point to point.
The transistor I recommended that you remove was the one closer to the IC, not the one that 's missing. I don't know if you had the other one out of the circuit.
I didn't get it exactly right. I would have thought that the conductive board was affecting pin 5 and apparently it's not.
Do you now have approximately 1/2v DC and a sawtooth waveform on pin 5?
The transistor I recommended that you remove was the one closer to the IC, not the one that 's missing. I don't know if you had the other one out of the circuit.
I didn't get it exactly right. I would have thought that the conductive board was affecting pin 5 and apparently it's not.
Do you now have approximately 1/2v DC and a sawtooth waveform on pin 5?
i hardwared the driver transistors away from the burned spot on the board, and i do have a 18KHz square wave on pins 9 and 10, only if they are on the air.
When i solder them nack to the circuit, pin 5 stops oscillating...
When i solder them nack to the circuit, pin 5 stops oscillating...
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