Protection circuit triggered - Electronic Circuits Projects Diagrams Free

amelecsol2000 · 12th August 2008, 03:59 AM

Hello to all,
I am working on an " MA Audio " high power audio amp. Model #HK401SX .
The protection circuit is triggered. I can't get a service manual for this unit.

Pins 9 & 10 on the (PWM " TL494CN ") Bias the mosfets , should get 5VDC on each, I have 0VDC on these pins . All of the other pins read normal VDC including the oscillator output. I replaced the PWM with another but have the same results . Seeing as the other pins are normal the PWM should be faulty but that is not the case ???
Anyone have any sugestions or advice ? It sure would be appreciated !!!

PS. all of the mosfets test good.

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12th August 2008, 03:59 AM	(permalink)
amelecsol2000	Protection circuit triggered Hello to all, I am working on an " MA Audio " high power audio amp. Model #HK401SX . The protection circuit is triggered. I can't get a service manual for this unit. Pins 9 & 10 on the (PWM " TL494CN ") Bias the mosfets , should get 5VDC on each, I have 0VDC on these pins . All of the other pins read normal VDC including the oscillator output. I replaced the PWM with another but have the same results . Seeing as the other pins are normal the PWM should be faulty but that is not the case ??? Anyone have any sugestions or advice ? It sure would be appreciated !!! PS. all of the mosfets test good. __________________ If you believe you can't you are absolutely right!!!!