Yamaha RX-V685 Repair - Page 1
Forum section: electronics / repair

author: Jerky_san
author_rank: Newbie
timestamp: June 20, 2020, 10:30:36 pm
content: Hello, first I would just like to say no I'm not an electrical engineer but a computer scientist so just wanted to get that out of the way. Basically, I'd call myself a novice repair person.Anyways I was wondering if you all could help me try to repair this Yamaha RX-V685 receiver that I have. It has gone into protection mode and the diagnostic code ps2 prt 124. I have been completely unable to find a service manual for this particular device. hifiengine only carries the user guide sadly. What I did find was a v585 service manual which seems similar in a few ways(error codes) so I've been trying to use it to help me on my quest to fix this. So what I've done thus far is on the digital board I found ps2 prt and checked the voltage there. It does indeed spike to around 124 then settles down to around 91-92. It is provided via a ribbon cable that hooks to another board labeled OPE_3. That board has a wire directly from the powersupply which carries. +5AE, 7A, -5V,VE, 5V. When I tested it though only one appears to be carrying voltage though this may be because diagnostic doesn't fully power the device. It is also connected to a back plane board that has a ps2_prt port leading to the bottom mainboard. I have been unable to test things on that board with power applied due to the limitations of the lengths of the cables (and I don't want to short anything)The service manual for a v585 saysP1-2. PSPower supply voltage (PS) protection detectionThe voltage at 96 pin (PS1_PRT)/97 pin (PS2_PRT)/98 ping (PS3_PRT) of IC22 is displayedVoltage detectsPS1: +3.3S, AC_BL, +- 7APS2: +5A, 3.3T, +5VID, +VP, +-12RYPS3: +5.5VNormal ValuePS1: 29-118PS2: 135 to 191PS3: 132 to 168(reference voltage: 3.3V = 255)What I've tried is tracing the PS2_PRT from the digital through a ribbon cable to OPE_3 down the connecting pins to the main amplifier board and trying to trace over to eventually hit the power supply to see what part of the power supply is supplying the faulty power. I was wondering if anyone had any ideas as well? I can provide pictures and such if needed. I apologize that I am unable to find the service manual. I can say that none of the caps appear blown or even puffed a little. I can also say when it happened I didn't see any visible smoke just a slight burning smell. I've attempted to "sniff" through all the boards to find the one that smelled similar but sadly none of them have a smell anymore.Any help is greatly appreciated.

author: mzacharias
author_rank: Frequent Contributor
timestamp: June 20, 2020, 11:32:53 pm
content: email me at:mark_zacharias@sbcglobal.netand I can send you the service manual.mz

author: Jerky_san
author_rank: Newbie
timestamp: June 20, 2020, 11:37:45 pm
content: Email sent thank you very much for your assistance.

author: Jerky_san
author_rank: Newbie
timestamp: June 21, 2020, 04:26:07 am
content: So checking all the power pins on this "Operation 13" board I discovered a set of pins that feed ops 3 board are missing the -5v and +5v. Can anyone tell me by these diagrams if my assumption of that yes those should be powered is correct? They have test pads right next to them so I am assuming yes. All +5.5v up to on CB301 are sending 5.27v. T3001 appears functional as well and W3002 is sending 5.27v.

author: Jerky_san
author_rank: Newbie
timestamp: June 21, 2020, 03:13:07 pm
content: So this morning I finally got it to come on without power protection mode enabled. Even did a firmware update.. Was pretty excited but hooking it to speakers it appears most do not function and the ones that do just make popping noises. So.. probably why it turned on without power protection mode honestly.