I picked up a Denon AVR-S900W with no power. Eventually I found a shorted 5339 3.3v regulator chip/ic on the hdmi board. I replaced that and was able to power on the receiver but it behaved oddly. Some of the buttons on the front wouldn't work, the volume knob wouldn't work and it didn't output any hdmi signal. I thought I may have soldered the new chip on wrong so I took it off and did some searching around. Apologies for the lack of zoom to see things more clearly.
Service manual, on the page in question:
https://www.manualslib.com/manual/95...age=125#manual
Screenshot of same page, with my problem area.
The two ic's in the middle of the screenshot are the 5339 ones. If you can make it out, they both output 3.3v to a shared line with a resistor connecting the two. That resistor doesn't exist, but the pads do. With one ic installed, I'm getting the expected 3.3v on one pad, but I still get 1.1XX volts on the other pad that should only be connected to the other ic which has been removed. I expected to get 0v there.
I tested the 6 pin ic's that each line feeds and they all test the same via a diode test - So I don't suspect one of allowing current to backflow.
I am relatively new to this and this is the deepest I've gotten into a repair so far. I don't know if the short in the ic heated up some traces in the pcb and shorted them out. I'm also a bit up against my understanding of circuit design and how to make sense of what I'm seeing with my voltmeter or what I should be looking for at this point. Any hints or tips are greatly appreciated.
Thanks
Service manual, on the page in question:
https://www.manualslib.com/manual/95...age=125#manual
Screenshot of same page, with my problem area.
The two ic's in the middle of the screenshot are the 5339 ones. If you can make it out, they both output 3.3v to a shared line with a resistor connecting the two. That resistor doesn't exist, but the pads do. With one ic installed, I'm getting the expected 3.3v on one pad, but I still get 1.1XX volts on the other pad that should only be connected to the other ic which has been removed. I expected to get 0v there.
I tested the 6 pin ic's that each line feeds and they all test the same via a diode test - So I don't suspect one of allowing current to backflow.
I am relatively new to this and this is the deepest I've gotten into a repair so far. I don't know if the short in the ic heated up some traces in the pcb and shorted them out. I'm also a bit up against my understanding of circuit design and how to make sense of what I'm seeing with my voltmeter or what I should be looking for at this point. Any hints or tips are greatly appreciated.
Thanks
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