Hi,
I have this amp, and been repairing for a while,
It was missing the A signal on pin 5 out from the BD board.
got that fixed with replacing the opamps lm833.
Replaced the HC74 to on both sides,
and then got the signal to around 5.8 volt on A and B. with audio signal.
Then I mounted the board again back again, but then still dont se any sign of this trianglewave on pin 4(carrier).
Btw, What is the carrier signal ??
But the signal for A and B was ok, and Toggel A and Toggel B was also ok, with nice square wave.
Tried mount the fets back, but amp started to act up,
So i have these scematic but its simular , but on my version there are a bounch of transistors and diodes insteed of opamps.
pin 4 the Carrier, seems to go to the daugher board.
On the backside of the board I marked red dot and 3 yellow, is lm833, and
I replaced all 4.
but weired thing is that the yellows has + & -12volts as they should, but the red dot, have 12 volt on pin 8 and -6 volt on pin 4.
And I double check its fysical connected to -6 pin.
is it manuafactured misstake.. ?
Any one sitting with a scematic of 1325-55947-02,
Sent request to USA, but the said they did not have it.
best regards
Niklas.
I have this amp, and been repairing for a while,
It was missing the A signal on pin 5 out from the BD board.
got that fixed with replacing the opamps lm833.
Replaced the HC74 to on both sides,
and then got the signal to around 5.8 volt on A and B. with audio signal.
Then I mounted the board again back again, but then still dont se any sign of this trianglewave on pin 4(carrier).
Btw, What is the carrier signal ??
But the signal for A and B was ok, and Toggel A and Toggel B was also ok, with nice square wave.
Tried mount the fets back, but amp started to act up,
So i have these scematic but its simular , but on my version there are a bounch of transistors and diodes insteed of opamps.
pin 4 the Carrier, seems to go to the daugher board.
On the backside of the board I marked red dot and 3 yellow, is lm833, and
I replaced all 4.
but weired thing is that the yellows has + & -12volts as they should, but the red dot, have 12 volt on pin 8 and -6 volt on pin 4.
And I double check its fysical connected to -6 pin.
is it manuafactured misstake.. ?
Any one sitting with a scematic of 1325-55947-02,
Sent request to USA, but the said they did not have it.
best regards
Niklas.
I went to supplier for Norway, they only got the 1405 serie.
I then sent request from USA, got answer to contact Norway, and
then asked again and they closed the request.
Attach pictures this time 🙂
I then sent request from USA, got answer to contact Norway, and
then asked again and they closed the request.
Attach pictures this time 🙂
Attachments
Disconnect the center legs of the rectifiers. Do the signals remain (as they were before reinstalling the board) on the driver board pins?
If you have the square waves, the carrier has to be present.
If you have the square waves, the carrier has to be present.
Mosfets getting hot,
Hi, Perry,
I got the output board fixed now but
the same problem still exist since when i got it,
The Mosfets overheat after about 30 minutes.
then signal dissapear and acting up. the heatsink getting real hot too.
The signal and squarewave looks like they suppose too, i belive.
Any experiance with this. ?
best regards
Niklas.
Hi, Perry,
I got the output board fixed now but
the same problem still exist since when i got it,
The Mosfets overheat after about 30 minutes.
then signal dissapear and acting up. the heatsink getting real hot too.
The signal and squarewave looks like they suppose too, i belive.
Any experiance with this. ?
best regards
Niklas.
If allowed to play at low volume (just loud enough to know when it stops playing), does the amp stop working as described above?
At low volume how long doe it take for the heatsink to become too hot to hold your hand on, continuously?
Does heating/cooling any part of the main or driver board cause the amp to quit playing?
At low volume how long doe it take for the heatsink to become too hot to hold your hand on, continuously?
Does heating/cooling any part of the main or driver board cause the amp to quit playing?
I will test tormorrow, but as i remember the driver board getting hot too. and with out the amp mountet, and mosfets not on heatsink they get very hot quick.