Hello,
I recently installed my old PC450 amplifier into a new car. I had this amplifier for years with no issues.
In the new car I immediately noticed the amp got very hot and stopped outputting. I did not have an inline fuse installed.
I powered up with a current limited supply and found the output transistors were getting very hot. I removed them from the board and checked for shorts but found none. I replaced anyway and still have the same problem with new fets.
The amplifier powers up normal drawing normal current then after about 30 seconds it draws max current limit from the supply (5A) and all outputs get hot for all 4 channels.
Currently only the outputs for CH1 are on the board and the problem still occurs.
Any help would be greatly appreciated!😀
I recently installed my old PC450 amplifier into a new car. I had this amplifier for years with no issues.
In the new car I immediately noticed the amp got very hot and stopped outputting. I did not have an inline fuse installed.
I powered up with a current limited supply and found the output transistors were getting very hot. I removed them from the board and checked for shorts but found none. I replaced anyway and still have the same problem with new fets.
The amplifier powers up normal drawing normal current then after about 30 seconds it draws max current limit from the supply (5A) and all outputs get hot for all 4 channels.
Currently only the outputs for CH1 are on the board and the problem still occurs.
Any help would be greatly appreciated!😀
Cant find a circuit diagram , not even on US car audio websites.
In the manual it mentions 1.5 amps "idling current " so yes 5amps shows a fault condition.
It looks like the bias and/or driver section is faulty but that's only one point it's also possible that a HF oscillation is driving the mosfets with a very large signal .
This can be down to a faulty compensation capacitor or a smoothing capacitor but this is only the tip of the iceberg , its very hard to narrow this down without a schematic so its just a quick "judgement call " and not a concrete evaluation.
In the manual it mentions 1.5 amps "idling current " so yes 5amps shows a fault condition.
It looks like the bias and/or driver section is faulty but that's only one point it's also possible that a HF oscillation is driving the mosfets with a very large signal .
This can be down to a faulty compensation capacitor or a smoothing capacitor but this is only the tip of the iceberg , its very hard to narrow this down without a schematic so its just a quick "judgement call " and not a concrete evaluation.
It worked in the old car. Not in the new car.
What changed?
I would re-re-re-check the speaker wiring. Even disconnect from amplifier and measure Ohms to ground-- should probably be infinity everywhere.
Isn't there a Car Audio section here? https://www.diyaudio.com/forums/car-audio/
What changed?
I would re-re-re-check the speaker wiring. Even disconnect from amplifier and measure Ohms to ground-- should probably be infinity everywhere.
Isn't there a Car Audio section here? https://www.diyaudio.com/forums/car-audio/
Hello @duncan2,
I was not able to find a schematic for this either. Just the owners manual. It definitely seems to be a biasing problem as you said. The outputs definitely seem to be getting turned on when no signal is applied. I will be reposting in the car audio forum as @PRR suggested.
Thanks
I was not able to find a schematic for this either. Just the owners manual. It definitely seems to be a biasing problem as you said. The outputs definitely seem to be getting turned on when no signal is applied. I will be reposting in the car audio forum as @PRR suggested.
Thanks
Hello @PRR,
I had the amp installed and working in car 1 for many years with no issues. In car 2 I had a very hastily wired setup and I believe one of the outputs shorted when I was driving. I will be moving this post to the car audio section as you suggested.
Thanks
I had the amp installed and working in car 1 for many years with no issues. In car 2 I had a very hastily wired setup and I believe one of the outputs shorted when I was driving. I will be moving this post to the car audio section as you suggested.
Thanks