| Electronics > Repair |
| OPA150 Stereo AMP issues, only turns on when I physically heat it up w/ a dryer! |
| << < (5/6) > >> |
| wraper:
Look where traces from zener diode go. Problem should be somewhere around it. What is the part on small aluminium heatsink? |
| N19htmare:
It's a c2800y mosfet. I've checked all the traces with a multi-meter and light and whatnot and I just couldn't see anything, if there is a break, it has to be microscopic but a slight change in temp is all it takes. I I think im going to try and find as many points I can around that area and connect them via wire and try to bypass the trace. The fact that the power board solders onto the daughter channel boards, it's a pain in the butt the de-solder and remove the power board. The amp boards to me are placed/design poorly. If you look at the Power board, it screws on to the large aluminum block which is supposed to act as a heat sink for the MOSFETS on the channel boards. However the 4 screws holding the board to the aluminum block are on opposite ends. When screwed into the block, there's basically a tug war going on between the two sides of the power board. The constant cooling/heating of the block has over time caused micro fractures in the PCB. That's my theory atleast. Unless there's a possibility it could still be a different component? |
| N19htmare:
double post |
| Greyleopard66:
Did this get resolve? I have problems with (2) APA150 and would like to know your resolution. |
| wires:
--- Quote from: Greyleopard66 on August 03, 2021, 07:38:28 pm ---Did this get resolve? I have problems with (2) APA150 and would like to know your resolution. --- End quote --- I had the same issue with 2 APA-150's. After about 5-years, the soft start starts to click on and off and then will fail to turn on the speaker outputs. The issue isn't the zener, it's the capacitor for the soft-start. They use a RC delay on a 220uF capacitor (C37). Once the capacitor reaches sufficient voltage, Q14 turns on the left right speaker relays. In one of mine, C39 had a slightly bulging top (also 220uF) so I replaced it at the same time. That large R79 resistor has heat stains on the bottom of the PCB, so I suspect it's "baking" that capacitor a bit. It's a bit of a pain to de-solder those 4-pin power connectors on the top sides of the board so that you can get it off the amp to work on it. You might be able to grab the cap with pliers, yank it off and tack on a new cap from the top side. I've added a picture to show the parts replaced. C39 was a 220uF/16V, C37 220uF/25V. Just use 25V or larger for both to make it easy. |
| Navigation |
| Message Index |
| Next page |
| Previous page |