Hi, been reading the posts on the forum for a while and learned plenty. But i seem
to have a problem with 2 of my amps, they are p-miller rsa-75hc, very nice sounding amps.they run 1 ohm stereo. Anyway here is my problem, i can't seem to run the amp when both left and right power supply mosfets(irf46n)are installed 3 on each side. When i take the left side out the amp runs fine, even produces sound. Now when i install the power supply mosfets on the left side back, it will turn on for a second and then shut down,I measured with a scope and get nice square waves on each power supply resistors, the tl494 is running fine, no shorts, on any of resistors, caps, or diodes, i searched over and over. I know the outputs are ok because i can get it running with 3 mosfets, if some one has a suggestion i would be grateful. And i replace the dual diodes on both sides and that's not the problem.
to have a problem with 2 of my amps, they are p-miller rsa-75hc, very nice sounding amps.they run 1 ohm stereo. Anyway here is my problem, i can't seem to run the amp when both left and right power supply mosfets(irf46n)are installed 3 on each side. When i take the left side out the amp runs fine, even produces sound. Now when i install the power supply mosfets on the left side back, it will turn on for a second and then shut down,I measured with a scope and get nice square waves on each power supply resistors, the tl494 is running fine, no shorts, on any of resistors, caps, or diodes, i searched over and over. I know the outputs are ok because i can get it running with 3 mosfets, if some one has a suggestion i would be grateful. And i replace the dual diodes on both sides and that's not the problem.
Another amp problem.
Hi, I would check to see if you have a shorted drive transistor on one bank of mosfets. Another cause could be a shorted diode in the bridge rectifier. Half the mosfets would only create one half of a square wave. If that half does not have the shorted diode then it may allow the supply to run. I'd check the drive transistors first. Regards, Steve
Hi, I would check to see if you have a shorted drive transistor on one bank of mosfets. Another cause could be a shorted diode in the bridge rectifier. Half the mosfets would only create one half of a square wave. If that half does not have the shorted diode then it may allow the supply to run. I'd check the drive transistors first. Regards, Steve
Thanks for the replys, well, i tried all your ideas, i still have the same results, when
i remove the right side mosfets and install the left side the mosfets will get really
hot, and eventually will burn the mosfets, so there is something wrong with that side, i narrowed it
down to there. I checked all the drive transistors and the bridge rectifiers and there all ok.Now, for the
shorted primary what am i looking for on the scope. And i really doubt the burnt ground trace,underneath the amp is heavy solder on all the traces.
i remove the right side mosfets and install the left side the mosfets will get really
hot, and eventually will burn the mosfets, so there is something wrong with that side, i narrowed it
down to there. I checked all the drive transistors and the bridge rectifiers and there all ok.Now, for the
shorted primary what am i looking for on the scope. And i really doubt the burnt ground trace,underneath the amp is heavy solder on all the traces.
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