Hi all,
I have started my journey repairing amps during this pandemic and it has been thoroughly rewarding.
Thanks to reading through this fantastic forum I was able to repair a handful of friends and relatives amps. 👍👌🏼👌🏼
My knowledge is very basic but I am willing to learn.
I have now come across an issue with an amp that powers up fine (Orion HP-4800), no protect light, but the volume output is very low on all channels. I cranked the gain to the max and no change in output AC voltage at the speaker terminals, the RCA input voltage I used was about 250mv with a 40hz sine wave. I removed the gain pot and tested the resistance and it was fine. I checked all the output Fets for shorts and they where also all fine. I am thinking there is something wrong on the preamp section that I need to check or replace, but I don't know where to start.
Anyone's help would be greatly appreciated.
Regards Jay
I have started my journey repairing amps during this pandemic and it has been thoroughly rewarding.
Thanks to reading through this fantastic forum I was able to repair a handful of friends and relatives amps. 👍👌🏼👌🏼
My knowledge is very basic but I am willing to learn.
I have now come across an issue with an amp that powers up fine (Orion HP-4800), no protect light, but the volume output is very low on all channels. I cranked the gain to the max and no change in output AC voltage at the speaker terminals, the RCA input voltage I used was about 250mv with a 40hz sine wave. I removed the gain pot and tested the resistance and it was fine. I checked all the output Fets for shorts and they where also all fine. I am thinking there is something wrong on the preamp section that I need to check or replace, but I don't know where to start.
Anyone's help would be greatly appreciated.
Regards Jay
It may be the power supply, which is shared among the channels.
Measure the DC supply voltage, which may be marked on the board.
Alternatively, could be the mute circuit or protection circuit, if the supply voltage is normal.
There is reverse power supply protection, maybe the series diode is bad.
Measure the DC supply voltage, which may be marked on the board.
Alternatively, could be the mute circuit or protection circuit, if the supply voltage is normal.
There is reverse power supply protection, maybe the series diode is bad.
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