hi to all
i have been around a lot but this is my first post.
i just blown my yamaha amp buy adjusting its bias almost to the max. fortunately nothing in the output devices failed ( i think so) but the power supply devices blew up (swithch mode) leaving black smoke on its surroundings. do anybody have the same expereince? what did i do wrong?
help
i have been around a lot but this is my first post.
i just blown my yamaha amp buy adjusting its bias almost to the max. fortunately nothing in the output devices failed ( i think so) but the power supply devices blew up (swithch mode) leaving black smoke on its surroundings. do anybody have the same expereince? what did i do wrong?
help
My experiences with switch mode psu's says that if one component there fails MANY others probably will..
I've looked at a couple of yamaha schematics on pdf and they are'nt too complicated in the power amp , You could at least try to measure the transistors with mutimeter diode function, dont rely on it though! transistors may be "half" broken..
I've looked at a couple of yamaha schematics on pdf and they are'nt too complicated in the power amp , You could at least try to measure the transistors with mutimeter diode function, dont rely on it though! transistors may be "half" broken..
Hi RICMAN,
Rereading, I see you have let the really expensive smoke out of the box. Could be fun, but not impossible to fix.
To repair switching supplies, you need a way to vari the power so it doesn't just go bang if there is another fault. Another bipolar variable power supply may allow you to troubleshoot and fix the output stage.
Wishing you luck with this.
-Chris
Rereading, I see you have let the really expensive smoke out of the box. Could be fun, but not impossible to fix.
To repair switching supplies, you need a way to vari the power so it doesn't just go bang if there is another fault. Another bipolar variable power supply may allow you to troubleshoot and fix the output stage.
Wishing you luck with this.
-Chris
The work to do, i am afraid, is more ressurection than repair
Because of switching power supply and over bias....extremelly overbiased...will be lucky to find fusistors burned.
I think this amplifier soul is already in the skies.
Sorry....bad luck for you....a hard to work to fix...and no guaranteed that the cost of parts are adequated to the equipment used market value....maybe parts turn expensive to put it in order again....those output transistors are highly selected...they are very well matched...hard to find matched units to substitute them....factory use to order sequence of transistors from the same silicon wafle...almost identical units.
regards,
Carlos
Because of switching power supply and over bias....extremelly overbiased...will be lucky to find fusistors burned.
I think this amplifier soul is already in the skies.
Sorry....bad luck for you....a hard to work to fix...and no guaranteed that the cost of parts are adequated to the equipment used market value....maybe parts turn expensive to put it in order again....those output transistors are highly selected...they are very well matched...hard to find matched units to substitute them....factory use to order sequence of transistors from the same silicon wafle...almost identical units.
regards,
Carlos
hi ricman
i once had similar problem with an old akai power amp
it had switching supply to make it light and sleak, which died after a while
i replaced it with outside trafo/rectifiers and caps
sounds great till now
i would not waste time with switching power supply
get the external and start replacing blown parts in the amp
don't give up
good luck
e
i once had similar problem with an old akai power amp
it had switching supply to make it light and sleak, which died after a while
i replaced it with outside trafo/rectifiers and caps
sounds great till now
i would not waste time with switching power supply
get the external and start replacing blown parts in the amp
don't give up
good luck
e
Good idea...removing switching supply and installing a standard supply
Will be more easy to fix...as two problems at same time is complicated...to fix the amplifier you need to trust in your supply.
That's a very good idea.....remove supply, substitute by another you prepare, needing more voltages will be easy to prepare with zener and transistors...just tell me the voltage you have and the voltages you need and i can do it for you...and them go to fix the amplifier.
Have some schematic?.....without it may be more difficult...but not impossible.... remove transistors, one by one, in the power unit, and check them...in advance...disconnect all supply wiring...cut keeping color code into the amplifier board...and measure from plus to ground and from negative to ground searching for short circuits....but remove supply.... as the short can be produce be the supply....well...working hard...you may ressurect it.
regards,
Carlos
Will be more easy to fix...as two problems at same time is complicated...to fix the amplifier you need to trust in your supply.
That's a very good idea.....remove supply, substitute by another you prepare, needing more voltages will be easy to prepare with zener and transistors...just tell me the voltage you have and the voltages you need and i can do it for you...and them go to fix the amplifier.
Have some schematic?.....without it may be more difficult...but not impossible.... remove transistors, one by one, in the power unit, and check them...in advance...disconnect all supply wiring...cut keeping color code into the amplifier board...and measure from plus to ground and from negative to ground searching for short circuits....but remove supply.... as the short can be produce be the supply....well...working hard...you may ressurect it.
regards,
Carlos
thanks a lot for your info
i have been busy with my job dont have a lot of time to drop by here.
BTW you are right all the output devices are shorted 6 parallel 2sa1492/2sc3856, the smp-supply devices are all blown up, a lot of money to spend
. any suggestions for a direct substitute for the audio-output devices? the power supply has a 135v per rails ( i don't know exactly)
"so i need a service manual."
Nikwal can you please send me a pdf yamaha s-manuals you have seen?
i've contacted yamaha their response is:
You can request service documents and user manuals from the company Lange in Berlin. The Lange team will answer all requests regarding availability, delivery times and prices.
Please contact them at the address given below.
Your Serviceteam
Yamaha Elektronik Europa GmbH
Address:
Schaltungsdienst Lange oHG
Zehrensdorfer Straße 11
12277 Berlin
Tel.: (030) 723813
Fax: (030) 72381500
Internet: www.schaltungsdienst.de
unfortunately the only payment they accept is via credit card which i don't have.
if somebody is near in this place i can just send him the money thru western union.
please help! i badly need the service manual as i don't want to blow those very expensive devices again.
any help would be greatly appreciated...
i have been busy with my job dont have a lot of time to drop by here.
BTW you are right all the output devices are shorted 6 parallel 2sa1492/2sc3856, the smp-supply devices are all blown up, a lot of money to spend
. any suggestions for a direct substitute for the audio-output devices? the power supply has a 135v per rails ( i don't know exactly) "so i need a service manual."
Nikwal can you please send me a pdf yamaha s-manuals you have seen?
i've contacted yamaha their response is:
You can request service documents and user manuals from the company Lange in Berlin. The Lange team will answer all requests regarding availability, delivery times and prices.
Please contact them at the address given below.
Your Serviceteam
Yamaha Elektronik Europa GmbH
Address:
Schaltungsdienst Lange oHG
Zehrensdorfer Straße 11
12277 Berlin
Tel.: (030) 723813
Fax: (030) 72381500
Internet: www.schaltungsdienst.de
unfortunately the only payment they accept is via credit card which i don't have.
if somebody is near in this place i can just send him the money thru western union.
please help! i badly need the service manual as i don't want to blow those very expensive devices again.
any help would be greatly appreciated...
Hi RICMAN
You can do a search for that diagram on this site, downloads are free. I know they have alot of yamaha schematics, just need to check for your model.
http://www.eserviceinfo.com/
Regards,
Werner
You can do a search for that diagram on this site, downloads are free. I know they have alot of yamaha schematics, just need to check for your model.
http://www.eserviceinfo.com/
Regards,
Werner
yamaha p7000s schematic needed
hi thanks for the link it will be helpful i think,
a follow up:
it's very difficult to find matched audio devices can i used unmatched devices? i'm also thinking of using onsemi transistors mjl3281 rather than the original sanken 2sa1492/3856 devices, will it have any difference or improvement to my amp?
need schematic if somebody out there can provide
still looking for the service manual for my yamaha pro-amp P7000S
is anybody out there who can give me i'll be willing to pay for it.
thanks for any suggestions/opinions...
hi thanks for the link it will be helpful i think,
a follow up:
it's very difficult to find matched audio devices can i used unmatched devices? i'm also thinking of using onsemi transistors mjl3281 rather than the original sanken 2sa1492/3856 devices, will it have any difference or improvement to my amp?
need schematic if somebody out there can provide
still looking for the service manual for my yamaha pro-amp P7000S
is anybody out there who can give me i'll be willing to pay for it.
thanks for any suggestions/opinions...
www.schaltungsdienst.de , 8.56 euro ($ 10) + shipping, english language service manual.
1 YAMU SERVICE MANUAL P7000S GB 1473416 PA011756
Get someone with a creditcard (your Dad??) to order it.
Jan Didden
1 YAMU SERVICE MANUAL P7000S GB 1473416 PA011756
Get someone with a creditcard (your Dad??) to order it.
Jan Didden
hi janneman
unfortunately i don't know someone who have a credit card also i can't afford to have a credit card, one more thing i'm not a little child anymore just like my avatar i'll be 30 this coming month
btw can you help me please janneman?
i would also like to get one for my yamaha rx-1500 a/v amp.
my posts are still moderated
it takes time before being posted
unfortunately i don't know someone who have a credit card also i can't afford to have a credit card, one more thing i'm not a little child anymore just like my avatar
i'll be 30 this coming monthbtw can you help me please janneman?
i would also like to get one for my yamaha rx-1500 a/v amp.
my posts are still moderated
it takes time before being posted
hi ricman
i can help, email me exactly what you need to order here
i will send it to you
eorvisky@yahoo.com
ed
i can help, email me exactly what you need to order here
i will send it to you
eorvisky@yahoo.com
ed
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