Yamaha Av receiver protection circuit problem - Page 1
Forum section: electronics / repair

author: ahmedmktdu
author_rank: Newbie
timestamp: February 02, 2019, 09:04:16 am
content: I have a Yamaha Rx-v 1067 (L model)My receiver shows Ps2 prt 169According to service manualP1-2. PS1/PS2Power supply voltage protection detectionThe voltage at 2 pin (PS1_PRT)/1 pin (PS2_PRT) of IC902 are displayed.Voltage detectsPS1: +3.3s, ACBL, ACM1, ACM2, +5,DCDC, -3.3V, +3.3HDR (U model)PS2: ±12A, ±12RY, +5A, +44V, +5DKNormal valuePS1: 84 to 141 (Nomal), 132 to 190 (PUREDIRECT)PS2: 81 to 153(Reference voltage: 3.3 V=255)* If PS1 or PS2 becomes out of the normalvalue range, the protection function worksto turn off the power.According to service manual ps2 line has 1.6 v (that means Ps2 prt 124 is ideal) but I found 2.18v (Ps2 prt 169). Higher normal range Ps2 prt 153 (1.98V).I measured all power supply DC volt is ok (±12A, ±12RY, +5A, +44V, +5Dk) then why the protection circuit volt is not in normal range?After that I also use a series 100W light bulb in ac and connect my receiver, light is glow a little and all the DC volt drop 12v down to 10v and 44 down to 30v in that situation ps2 part volt goes down to 1.8 and its work fine (as its came down to normal range) (but its not a solution)Service manual link:https://drive.google.com/open?id=11gXNl8_cLPWHVZpx68tvevcZ8klxmXItAny help would save me. Thanks

author: ahmedmktdu
author_rank: Newbie
timestamp: February 02, 2019, 09:15:22 am
content: when i de-assemble the receiver i found video 2 power Bord (page 124 in service manual) has some kind of oily liquid in pcb. i clean that, i measured all volt is fine. is there any short? how to chk ? but my problem is not solve . what to do next?

author: highdesert56
author_rank: Contributor
timestamp: February 02, 2019, 10:39:59 am
content: I would try to identify the component that leaked all over the board, assuming that it wasn't an environmental ingress.Other than that, if you cleaned it and it works, just use it as long as it's working fine and not filling the room with smoke.I just saw the part about it not working still...Is it possible it needs a factory reset to clear the shutdown condition if the voltages are now normal?

author: PKTKS
author_rank: Super Contributor
timestamp: February 02, 2019, 10:54:03 am
content: It looks bad.Or something spilled over the board or it leaked a lot by itselfEither case I would start removing the board.Removing all caps and sensible parts - RECAP all stuffClean the board to the max possible and reassemble to do more testsAnything prior to this is lucky shot ...

author: ahmedmktdu
author_rank: Newbie
timestamp: February 02, 2019, 11:59:13 am
content: i chked all the volt out from this board is correct, then how i understand the leakage? i de solder all big size electrolyte cap and test with cheap china component testers the result is here: 3300uf show esr=0.01, vloss=2.5% 2899uF, 6800uf show esr=0.01, vloss=1.6% 6336uf, another one show esr=0.00, vloss=1.9% 6490uf, other one esr=0.00, vloss=2.2% 6404uf, are all caps ok?

author: ahmedmktdu
author_rank: Newbie
timestamp: February 02, 2019, 12:14:47 pm
content: the receiver working whey i bypass the protection by pressing info+tone control+ power (no protection mode), around a hour i played song and its nothing frayed up! resetting also not solved the problem, with series light bulb connection (this condition ps2 prt show 143) trying to update the firmware but at this point protection work and its shows ps2 prt: 155, when the normal range is 153. so i cant update in any condition. looking for farther instruction

author: PKTKS
author_rank: Super Contributor
timestamp: February 02, 2019, 01:02:23 pm
content: I would follow the best practices...Remove the board. Clean the best you canRECAP. Better safe than sorry.Just a dozen caps won't harm your budget.Restart the routine

author: ahmedmktdu
author_rank: Newbie
timestamp: February 02, 2019, 01:49:36 pm
content: in my country its hard to find best quility cap. if i use general cap i think it will make more problem. as the protection circut is very sensetive. if i order from ebay it will take around 30 days. i will do this if i dont find other option. but i just wana sure the caps make the problem when the output volt is perfect?

author: PKTKS
author_rank: Super Contributor
timestamp: February 02, 2019, 01:59:17 pm
content: Quote from: ahmedmktdu on February 02, 2019, 01:49:36 pmIf I start a contest here about mine.. All prices are at least 3x around here.I will not whine (i do that all day long searching prices and parts...)The PUDIM nowadays is CHINA. They are still ( and should be for long time ) unbeatablefor ELETRO-eletronic parts go AliExpress. You will find a lot of good stuff. Best pricesHere it takes at least 3 month to get on site. But still the best choice.Electronics industry and industry here are destroyed by politicians since 70/80sI don't ramble as at least there is an option left although prices are a big issueIn repair and maintenance the price tag is a very hard to craft balanced middle pointPaul