I recently acquired a Yamaha PD2500 power amp, gratis. It was initially in a protect mode unless the chassis was physically lifted in the front left corner. I have completely stripped the unit and re-soldered everything (full of cold / dry joints), fully cleaned and replaced all the sil-pads. There were two bad caps and one burned resistor on an auxiliary power supply, replace bad components (was symetrical so I could infer bad resistor value from undamaged rail). It now seems to be in working order. I would like to verify things like bias settings but have no references for this unit.
I have not been able to get my hands on the service manual or even just the schematic. Does anyone have a link or a copy of the relevant information?
I haven't given this a listen yet, any opinion wether it is worth any further effort?
I have not been able to get my hands on the service manual or even just the schematic. Does anyone have a link or a copy of the relevant information?
I haven't given this a listen yet, any opinion wether it is worth any further effort?
Whene I was repairing older Yamaha p3200 ? not sure about the model.....
I emailed them and they send me service manual with schematic and calibration procedure.......so you can try to email them.....
If you want I can send you service manual for 3200 and maybe it is similar.....But I'm in London and service manual is somewhere at the comp based in my lab in Ljubljana.......so if you need it I can arrang something.....my brother maybe can.......
Regards, Taj
I emailed them and they send me service manual with schematic and calibration procedure.......so you can try to email them.....
If you want I can send you service manual for 3200 and maybe it is similar.....But I'm in London and service manual is somewhere at the comp based in my lab in Ljubljana.......so if you need it I can arrang something.....my brother maybe can.......
Regards, Taj
Thanks Tajzmaj, but I'm not sure how similar your unit is to mine. I'll send off an email (do you recall what the email address was?) and see if they are willing to send me any information.
I'm not sure about email address.....but if I remember correct than it was somehow regionally devided......I really don't know it was some two years ago. But they reply very fast.
Regards, Taj
Regards, Taj
I found a web page for submitting a query earlier today. They sent me the service manual, Parts list and PCB diagrams, but alas, no schematic nor any reference to bias settings.
I could just set it to give the 'ideal' 26mV across the emitter resistors, or 52mV across the test points and be done with it. Both channels measure different, one at ~32mV across the test points and the other at about 11mV. I'm fairly sure the low one was messed with by someone else.
I could just set it to give the 'ideal' 26mV across the emitter resistors, or 52mV across the test points and be done with it. Both channels measure different, one at ~32mV across the test points and the other at about 11mV. I'm fairly sure the low one was messed with by someone else.
He....everything is possible .... btw is this amp class ab or it is h class ?
Does it have only one +- voltage at psu ?
Because at p3200 there is more than one. And those output transistors are not all output transistors but some of them are rail trackers.....
And if I remember correct there were not very closely matched devices st the original......it is possible thet it was caused by several ,,hot gigs,,
Btw does yours amp work? I would set the idle at dome 10mV and observe. Do you have any of scope....? Because this is a ,,pro,, amp I wouldn't set idle too high. Espscially if you want to drive it hard.....heat is an enemy of pro audio amps which see a lot of ,,field,, abuse.
If it works I wouldn't touch it too much Just close it and use it.....
If you want to get perfect and symetrical idle bias readings than you will probably need to replace all outputs by closely matched new ones.....
I will ask my brother to find the p3200 service manual st my home so you will get it......in case that is too big please send me an email taj.pecnikar@gmail.com
It may helps you.
But dont undestand me wrong. I have some 30 Carver amps. All old ones. Some of them I bought dead or even uncomplete. And I service them that almost everything is perfect. All new matched outputs/comutators......all the same idle biac readings.......That's the way I like it but sometimes it isn't woth. A lot of money and a a lot of time. Of course batter performance and higher reliability. We of course don't want to have dead amp at the middle of some concert.....blah blah blah...🙂
Regards, Taj
Does it have only one +- voltage at psu ?
Because at p3200 there is more than one. And those output transistors are not all output transistors but some of them are rail trackers.....
And if I remember correct there were not very closely matched devices st the original......it is possible thet it was caused by several ,,hot gigs,,
Btw does yours amp work? I would set the idle at dome 10mV and observe. Do you have any of scope....? Because this is a ,,pro,, amp I wouldn't set idle too high. Espscially if you want to drive it hard.....heat is an enemy of pro audio amps which see a lot of ,,field,, abuse.
If it works I wouldn't touch it too much Just close it and use it.....
If you want to get perfect and symetrical idle bias readings than you will probably need to replace all outputs by closely matched new ones.....
I will ask my brother to find the p3200 service manual st my home so you will get it......in case that is too big please send me an email taj.pecnikar@gmail.com
It may helps you.
But dont undestand me wrong. I have some 30 Carver amps. All old ones. Some of them I bought dead or even uncomplete. And I service them that almost everything is perfect. All new matched outputs/comutators......all the same idle biac readings.......That's the way I like it but sometimes it isn't woth. A lot of money and a a lot of time. Of course batter performance and higher reliability. We of course don't want to have dead amp at the middle of some concert.....blah blah blah...🙂
Regards, Taj
I have the amp working and will likely err on the conservative side for the bias setting. I don't have a 'pro' use for this amp but I'll see how it sounds in a domestic setting. This is a class AB unit, not an H or other rail tracking variant. The schematic you provided is very different from the unit I have but thanks anyhow.
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