hi guys, im in the middle of fixing a crown csl800 amplifier that had a channel fully blown. it was outputing 50vdc always, it had almost every output transistor blown on that channel (i ordered parts to replace them all anyways). the drivers(to-220 transistors near outputs) where either shorted or one of the legs melted completely(replaced those too). also the r01 resistor between the base and emitter was burnt and some other small signal transistor were dead on the preamp board.
i have replaced a couple of parts, and now the amplifier will pass sound thru it, the issue now is that there is a high pitch sound when there is no audio input(or speaker connected to the amp) to the amp and if you hook up a speaker (8ohms) and some signal, the speaker will play what you give it without any distortion, but you can hear a high pitch version of the audio input coming from the pcb. it seems to possibly come from the big inductor right before the speaker output (L300). its important to note that the other channel is fully functionnal and does not do any of that.
but now i am out of ideas of what the problem could be, this is one of the first crown amplifier im fixing so i am not familiar with the design yet.
has anyone seen this before?could anyone point me in a direction that could lead me to find the problem?
any help is good help.
thanks!
i have replaced a couple of parts, and now the amplifier will pass sound thru it, the issue now is that there is a high pitch sound when there is no audio input(or speaker connected to the amp) to the amp and if you hook up a speaker (8ohms) and some signal, the speaker will play what you give it without any distortion, but you can hear a high pitch version of the audio input coming from the pcb. it seems to possibly come from the big inductor right before the speaker output (L300). its important to note that the other channel is fully functionnal and does not do any of that.
but now i am out of ideas of what the problem could be, this is one of the first crown amplifier im fixing so i am not familiar with the design yet.
has anyone seen this before?could anyone point me in a direction that could lead me to find the problem?
any help is good help.
thanks!
This PCB was one of the cleanest I've ever seen in an amp. Literally no dust inside
it may be too late but I have an update. the amp still has this issue but I have narrowed down where the noise is comming from the low side bias potentiometer (sound physically comes out of the potentiometer)
it may be linked to something that happened before. one of the diode was shorted and the trace all the way to the potentiometer lifted off the board because of heat. I will be trying to replace this potentiometer. anyone know where to get some?
it may be linked to something that happened before. one of the diode was shorted and the trace all the way to the potentiometer lifted off the board because of heat. I will be trying to replace this potentiometer. anyone know where to get some?
Hi guys, i have problem with this amplifier. one channel has completly fault. i have replaced output transistors, smal resistors on the amp board, and one transistor and his emiter resistor on input board Q115 (MPS8097 in my case is MPSA18) and resistor R147 (200R) .
Amplifier always blown driver transistors after turning on without safe resistors on power supply. i'm double checked both board, everything is ok. All transistors are OK, all diodes are OK....
here is
Here is shematic becouse i can't upload (1.57MB)
Thanks!
Amplifier always blown driver transistors after turning on without safe resistors on power supply. i'm double checked both board, everything is ok. All transistors are OK, all diodes are OK....
here is
Here is shematic becouse i can't upload (1.57MB)
Thanks!
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