the amplifier arrived sulfated from the power supply, removing the excess of sulfate, dynamically testing it enters protection mode verifying the soft start voltages at terminal 8 and 11 of tl494 when the green indicator led enters the measured voltage is barely 6.5 V, thinking that it was a short in the secondary part of the source, isolate all the power transistors from the amplification section, check the soft start transitors that are Q71, Q72, Q73, finding in good condition, voltages of rail are very unstable from +26 and -28 v; some pictures of the amplifier amplifier
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It sounds like you're not providing enough voltage for the amp to power up.
Use the secondary ground to measure the rail voltage.
If the output transistors are out of the circuit, check for drive pulses on the gate pads of the output transistors.
The kx6001 diagram may be close to what you have:
Service manual, eprom result list | Elektrotanya
Use the secondary ground to measure the rail voltage.
If the output transistors are out of the circuit, check for drive pulses on the gate pads of the output transistors.
The kx6001 diagram may be close to what you have:
Service manual, eprom result list | Elektrotanya
It appears the soft start is not latching, because Q74-3875GR is not switching and pulling down the base of Q73-1505GR.
Pin 10 and Pin 8 of the U01-TL494 want to see a stable 12-13 volts for proper drive to the switching mosfets.
Pin 10 and Pin 8 of the U01-TL494 want to see a stable 12-13 volts for proper drive to the switching mosfets.
Checking the protections of the comparator KIA 339 in diode D16 there are 12 volts coming from the protec which in turn has leading to the transitor Q05, which voltages should have Q06 and C07
Try lifting R12-10K. This should allow the amp to remain powered up when increasing the gain without a load, but because the rails are unstable the output will be distorted.
If you monitor the voltage at the positive leg of C71 during power up you should see the DC voltage ramp up to about 6.5vdc and latch at ~12 volts. Use the secondary ground for the black probe of DVM.
If the voltages continue to fluctuate around 6.5 volts at Pins 8 and 11 of the TL494 the amp will have unstable rails and cause protection. The issue is most likely in the soft start circuit, and Q71,Q72,Q73 and Q74 are suspect.
If you monitor the voltage at the positive leg of C71 during power up you should see the DC voltage ramp up to about 6.5vdc and latch at ~12 volts. Use the secondary ground for the black probe of DVM.
If the voltages continue to fluctuate around 6.5 volts at Pins 8 and 11 of the TL494 the amp will have unstable rails and cause protection. The issue is most likely in the soft start circuit, and Q71,Q72,Q73 and Q74 are suspect.
Good night, the measurement that marked the 12 v was strange to me and I removed the transistor Q06 and when measuring it had a leak between the base and the collector, I sent it to ask since I do not have it at hand, I will comment on any advance, thank you for your comments are very helpful.