Harman kardon AVR 310 blow fuses

[freethink]

I'm trying to fix my Harman kardon AVR 310. Fuses FU484 and FU483 (on main board) are both blown. Unit powers up, but no sound and some front panel lights not working. I've tested all of the capacitors on the main board with my ESR meter, and 7 showed [in circuit / leaky] I removed 6 out of the 7 (one was super hard to get to) and they all tested fine. I also tested the caps on the stand by board, and found one at the top that was a cold solder joint, but I'm not sure if that had anything to do with the fused blowing or not. I also tested the 4 large diodes right after the fuses and those seem to be good as well. I'm wondering where to go from here. Anybody else run into this problem? Any help would be much appreciated. (I'm kind of a novice at electronics FYI) Thank you.

[FrozenHaxor]

Re: Harman kardon AVR 310 blow fuses

Please post pictures of the inside, especially area around those fuses and area with output power components.

[budm]

Re: Harman kardon AVR 310 blow fuses

Service manual: https://www.manualslib.com/download/...on-Avr310.html
1) So the blown fuses FU484 and FU483 are on the Main Amp board, PDF page 121.
2) Did you check D568, 569, 570, 571?
3) Did you check the resistance between GND (of that section of the power supply ) and the output side of the blown fuses to see if it shows low resistance?
4) Good clear of the pictures will also help.

[freethink]

Re: Harman kardon AVR 310 blow fuses

Service manual: https://www.manualslib.com/download/...on-Avr310.html
1) So the blown fuses FU484 and FU483 are on the Main Amp board, PDF page 121.
2) Did you check D568, 569, 570, 571?
3) Did you check the resistance between GND (of that section of the power supply ) and the output side of the blown fuses to see if it shows low resistance?
4) Good clear of the pictures will also help.

Hi, thank you for replying. Sorry I didn't reply sooner, I didn't get notifications for some reason. Yes, I checked checked those 4 diodes with the diode checker on my DMM, and they seem to be fine. The resistance between the fuses and ground, measures about 3.7 mega ohm. I uploaded some pics, let me know if there is an area that you need better pics of.

[freethink]

Re: Harman kardon AVR 310 blow fuses

Please post pictures of the inside, especially area around those fuses and area with output power components.

Hi, thank you for replying. I included some pictures below. The output transistors are kind of obscured by the fins on the heat sink. If you need better pics of any particular place, I'll try to get more.