No, it’s pulling too much current for me to get enough voltage to turn anything on. I tried a 20a supply and it popped the breaker.
With my 5 amp supply, if I leave it on for about 10-15 seconds, the voltage will rise to appx. 7volts. Then I get appx. 4v dc on the ps gates.
With my 5 amp supply, if I leave it on for about 10-15 seconds, the voltage will rise to appx. 7volts. Then I get appx. 4v dc on the ps gates.
Even at limited voltage, you should be able to see if all drive signals for both transformers are the same.
I get a drive signal from pin 7 of the 494.
Pin 7 of the 494 connects to the emitter of two 2sa1023 drivers. The bases of these two 2sa1023 are connected to the gates of the fets which are getting hot. I get appx 4v dc on these fet gates. No drive signal though I have drive aignal
pin 8 of the 494 connects to the remaining two 2sa1023 and only has a small dc signal. No drive present on pin 8.
Pin 7 of the 494 connects to the emitter of two 2sa1023 drivers. The bases of these two 2sa1023 are connected to the gates of the fets which are getting hot. I get appx 4v dc on these fet gates. No drive signal though I have drive aignal
pin 8 of the 494 connects to the remaining two 2sa1023 and only has a small dc signal. No drive present on pin 8.
Shouldn’t the 494 pins 7 and 8 connect the the bases of the driver transistors and not the emitters? Seems like these are in backwards though they are correctly oriented according to the board designation. Should would explain the behavior.
Yep, the drivers are inserted in the board backwards.
Also found two 1n4148 diodes open.
Replaced diodes and installed drivers properly, powered up board and got drive on pin 9 but still nothing on pin 10. Replaced the tl494 and got drive on pins 9 and 10 and all driver fets are working now. Amp idles at around 2 amps.
the output has 96v dc on the speaker terminals so it only powers up with d1 removed. I will start working on that next and report back what I find.
Also found two 1n4148 diodes open.
Replaced diodes and installed drivers properly, powered up board and got drive on pin 9 but still nothing on pin 10. Replaced the tl494 and got drive on pins 9 and 10 and all driver fets are working now. Amp idles at around 2 amps.
the output has 96v dc on the speaker terminals so it only powers up with d1 removed. I will start working on that next and report back what I find.