Is the amp completely dead or going into protect? If it's completely dead, post the DC voltages on the driver IC (TL494?).
IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
Attachments
Sinuslive repair
Hello
Now I have measured a bit in the amplifier again.
Transistor Q8 has a short circuit.
How many transistors in the ampifier do you recommend to be replaced?
All transistors Q1,2,3,4 and Q5,6,7,8?
Thanks for all for now
Best regards
Did you check all of the output transistors to determine if any had failed?
Hello
Now I have measured a bit in the amplifier again.
Transistor Q8 has a short circuit.
How many transistors in the ampifier do you recommend to be replaced?
All transistors Q1,2,3,4 and Q5,6,7,8?
Thanks for all for now
Best regards
Yes, you need to replace all 8 of the outputs. Since you only found one shorted, reinstall the others, clamp all of the transistors down (you'll have to place the blown one under the clamp so you can clamp the adjacent output down tightly) and power up the amp. Does it power up and produce audio (at low power output)?
Use a 15 amp fuse in the B+ line to protect the amplifier in case there is another problem.
Use a 15 amp fuse in the B+ line to protect the amplifier in case there is another problem.
Have you checked all of the driver transistors and the gate resistors for the outputs? Those commonly fail when the outputs fail.
Do you have an oscilloscope?
Yes I have
I have messured alot off DC voltage around U8-9 D16-D17 it´s looking fine now. Output has zero DC and I can load the amplifier (100W@4ohm for now)
BUT
The Power led in the amp will still not light up
Do you have any ideas for "protection voltage or ref voltage" for the protection circuit I can measure or am I still missing something here??
Best regards
Kim
Does it produce rail voltage?
If not, post the DC voltage on the TL494 (594) power supply IC.
IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:
The rail (psu) voltage is +- 62V
I that what you mean?
Kim
The "protect led" is lightning at start when you turn on the amp and then the led turns off again when the power amp is startet op
allright
But not the power led
I will measure TL 494 for you all 16 pins
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