Hello
I'm working on this JBL GTO24001
I arrive at my laboratory with the charred resistor R200 (2r2 5W). I replaced it and it is working perfectly, all the signals are in place, but the idle current is 10 amps. An atrocity.
I have checked with the thermographic camera every corner of the amplifier, but everything is normal. No component is overheating.
Has anyone had a similar problem?
Greetings.
I'm working on this JBL GTO24001
I arrive at my laboratory with the charred resistor R200 (2r2 5W). I replaced it and it is working perfectly, all the signals are in place, but the idle current is 10 amps. An atrocity.
I have checked with the thermographic camera every corner of the amplifier, but everything is normal. No component is overheating.
Has anyone had a similar problem?
Greetings.
Does anything start to get significantly hotter if you drive the amp to moderate power into a load?
What's the DC voltage across the B+ and ground terminals when it's drawing 10 amps?
What's the DC voltage across the B+ and ground terminals when it's drawing 10 amps?
I just did this test, with a 2 ohm load, draining 1200w and everything seems to be normal, nothing overheats excessively
Was the resistor the only problem when the amp came in for service?
Were all FETs clamped to the heatsink when you checked for heating?
Do all groups of FETs have about 10v of drive?
What's the oscillation frequency on the output and PS FETs?
Were all FETs clamped to the heatsink when you checked for heating?
Do all groups of FETs have about 10v of drive?
What's the oscillation frequency on the output and PS FETs?
yes, the only problem was the resistor R200. the mosfets were attached to the chassis. I also tried them without fastening to the chassis and none heats up more than another, significantly. the oscillation frequency is around 80khz (I don't know if it's normal) and around 10v
The 80kHz for the output is normal. It's determined by the output of pin 5 of the MC14060.
The PS should be about 20kHz.
The PS should be about 20kHz.
indeed, the train of pulses of the power supply is 20khz.
I don't know what else to check.... the most illogical thing is that in those 10A at rest, the current does not vary at all. If something overheated more than it should, the quiescent current would increase.....
I don't know what else to check.... the most illogical thing is that in those 10A at rest, the current does not vary at all. If something overheated more than it should, the quiescent current would increase.....
If you can't find any of the FETs overheating or any other excess heating) test the amp at full power (music up to intermittent clipping) for an extended period of time. If it passes, let it go.