Yamaha amp woes - Page 1
Forum section: electronics / repair

author: No1baggiesfan
author_rank: Newbie
timestamp: January 26, 2019, 03:08:46 pm
content: My Yamaha amp RX-V671 has decided it no longer wishes to operate :/I think we had a power surge/outage a couple of days ago as my PS4 informed me that I hadn't turned it off properly, it's usually left in rest mode to charge the pads, anyway, amp turned itself off when my wife turned it on, and then again, so I tried, same thing, I reset the amp, checked all speaker cablesthen powered it back on, success, it worked fine for about 45 mins then switched off again, now it will not stay on.Diagnostic mode gives the error: PS: PRT 135 H (the 135 value fluctuates from 130-145/ I have reset the amp 2-3 times)I also see a fluctuating value in p1-2 diagnostic: PS 160/129 which suggests a high volt error somewhere, 1.6v instead of 1.3v ?

author: mzacharias
author_rank: Frequent Contributor
timestamp: January 27, 2019, 04:08:30 am
content: How can you possibly expect any useful information if you have not provided so much as a(wait for it.....)MODEL NUMBER?sheesh.

author: PKTKS
author_rank: Super Contributor
timestamp: January 27, 2019, 12:22:18 pm
content: MODEL will helpAlthough YAMAHA is not very consistent among models and codes...The "PS" is for sure PowerSupply PANIC.The other codes usually indicate the best match for that.Diagram helps but YAMAHA audio gear is anything but simple to deal...Paul

author: No1baggiesfan
author_rank: Newbie
timestamp: January 29, 2019, 01:22:52 pm
content: Nobody at all ?

author: PKTKS
author_rank: Super Contributor
timestamp: January 29, 2019, 01:51:09 pm
content: Quote from: No1baggiesfan on January 29, 2019, 01:22:52 pmAlready stated. PSU for PowerSupply PANICPRT + CODE indicates best match latest reading

author: No1baggiesfan
author_rank: Newbie
timestamp: January 29, 2019, 08:44:09 pm
content: Panic ? Why ?

author: Chris56000
author_rank: Frequent Contributor
timestamp: January 29, 2019, 09:12:48 pm
content: Hi!Tut, tut, everyone, me fears you've all been ranting before reading the OP's post carefully – he gave the model no. in his first sentence – RX–V671!SM:–https://www.manualslib.com/download/919935/Yamaha-Rx-V671.htmlI'll have a read of this and come back later with fault–finding tips!Chris Williams

author: Armadillo
author_rank: Super Contributor
timestamp: January 29, 2019, 09:27:55 pm
content: His message was edited at "Last Edit: January 27, 2019, 08:09:45 pm by No1baggiesfan »"By editing message when others has posted replies isn't too wise, as the edited message will not be bumped up to the Top and no one reasonable minded is going to re-read original message with missing information.

author: David_AVD
author_rank: Super Contributor
timestamp: January 29, 2019, 09:31:26 pm
content: I've seen some of these amps (not that exact model, but similar) that have developed corrosion and intermittent vias / tracks on the top board (with processor). Possibly caused by dust coming through the top vents and then becoming damp with humidity. This causes all sorts of weird faults including random muting or shutdown. I'm fairly sure that I've seen one with the wavering / incorrect diagnostic reading. Finding the bad vias / tracks can be a time consuming exercise. Might not be the fault in your case, but worth keeping in mind.

author: No1baggiesfan
author_rank: Newbie
timestamp: January 29, 2019, 10:00:05 pm
content: Yes I did amend my post, I felt it wasn't necessary to post again when it could be edited. Apologies.Wavering values is a very good point, in the diagnostic mode,value p1-2 The value has been as low as 100/129 and as high as 160/129, I have sat and watched it dance about.To be honest tho, this amp is only 5 years old and it looks very clean inside.I have also noticed that the standby led no longer illuminates when ac is turned on, pretty sure I've read somewhere that this is linked to a 5v supply somewhere.

author: David_AVD
author_rank: Super Contributor
timestamp: January 29, 2019, 11:38:06 pm
content: Yeah, check all of the voltage rails as the TO-220 package regulators can go bad, particularly the KA78xx and KA79xx varieties.

author: PKTKS
author_rank: Super Contributor
timestamp: January 30, 2019, 10:34:36 am
content: Quote from: No1baggiesfan on January 29, 2019, 08:44:09 pmBecause it triggered the Protection Mode.PS (Power Supply): PRT (Protection Mode) XXXX (code for the PANIC read out ADC)Reason being vary widely - the fault itself should be ISOLATED on the MAINS PSUYAMAHA gear requires a proper step based analysis from top/bottom(e.g. left/right signal flow)Paul

author: No1baggiesfan
author_rank: Newbie
timestamp: January 30, 2019, 08:15:34 pm
content: Ok new development, I was checking video board for voltages, saw 4x 5.5v on the connector cb376.Still no standby 5vAnyway I turned off the amp (still got ac) and as I moved my MM I knocked the main zone button turning the amp back on, it's still on now 🤔Obviously there is still a fault as the red led is not illuminating.Loose connector somewhere ? Dry joint ? Gremlins

author: No1baggiesfan
author_rank: Newbie
timestamp: January 30, 2019, 08:52:46 pm
content: Me and my big mouth lol, she's off again

author: PKTKS
author_rank: Super Contributor
timestamp: January 31, 2019, 12:08:06 pm
content: don't waste your time poking around.YAMAHA gear requires proper methods.Disconnect mains PSU and gradually put them backuntil you are sure you have ISOLATED the fault.YAMAHA is not trivial to deal