Hello i am new here, i have this car amp where it wont come out of protection mode, originally problem was battery terminals were reversed.
I have replaced all transistors on the power supply side and 1 side of output transistors and found burnt traces(same side). That side seems good now. Also the 2 driver ics for what I think is output transistors. When everything is together, I get the red light flashing twice and manual says that means voltage is under 9 volts. I am giving 12 v of course, but 4 rectifiers are getting about 8-9V and the other 4 (outer ones) have 0 volts on all legs. This is my first time repairing an amp so idk if it should be like that for the outer ones, but i heard that somewhere around there, there should be a high dc voltage like maybe 80 volts, created from the transformers, that is nowhere to be found, so i think the "gate driver(s)" is the issue and it is not pulsing the transistors on the psu side? Sorry i dont know much, just appears that no high voltage is coming out from the transormers or transistors. I found these 2 tiny ic chips and think they might be the ones responsible for pulsing but i am not sure. I will attach pictures, i cant find these ic parts online either way. The picture has the ic blurry so here is what they say: "8CA 524A". They are smaller than DS0 package size. Also when i removed rectifiers, amp stays on protect mode steady red light but i dont think thats useful. The ic's i already changed are the "s18244 " ones btw(i think this is for output fets). Any help would be appreciated
I have replaced all transistors on the power supply side and 1 side of output transistors and found burnt traces(same side). That side seems good now. Also the 2 driver ics for what I think is output transistors. When everything is together, I get the red light flashing twice and manual says that means voltage is under 9 volts. I am giving 12 v of course, but 4 rectifiers are getting about 8-9V and the other 4 (outer ones) have 0 volts on all legs. This is my first time repairing an amp so idk if it should be like that for the outer ones, but i heard that somewhere around there, there should be a high dc voltage like maybe 80 volts, created from the transformers, that is nowhere to be found, so i think the "gate driver(s)" is the issue and it is not pulsing the transistors on the psu side? Sorry i dont know much, just appears that no high voltage is coming out from the transormers or transistors. I found these 2 tiny ic chips and think they might be the ones responsible for pulsing but i am not sure. I will attach pictures, i cant find these ic parts online either way. The picture has the ic blurry so here is what they say: "8CA 524A". They are smaller than DS0 package size. Also when i removed rectifiers, amp stays on protect mode steady red light but i dont think thats useful. The ic's i already changed are the "s18244 " ones btw(i think this is for output fets). Any help would be appreciated
Attachments
Those small ICs are the gate drivers for the power supply mosfets. UCC27524A (Dual 5amp high speed gate driver).
Ohhh. Thank you so much! I will order 2 replacements. I am not good with identifying these small components
That’s a large amp to jump on right out of the gate. The area circled is probably going to be your undervolt circuit so troubleshoot that area. Make sure you’ve checked all of the diodes and gate resistors around the output mosfets. Also check all gate resistors in the power supply. It’s been my experience that weird things happen in these amps when voltage is reversed. So don’t assume anything survived. If in doubt check it.
Attachments
okay i will make sure to check all gate resistors. just checking for resistance value right. and any tips for troubleshooting the undervolt circuit? thank you so much
Those power supply gate drivers are directly driven by the programable IC. I believe it is marked MC1 in your amp. As long as that IC thinks there is a problem with the amp it will not send pulses to the gate driver ICs for the power supply. That’s probably why your power supply is sitting idle.
David
David
The DR version has a bigger footprint and no thermal pad on the bottom. The first one in that list should be the right one.
