Got my hands on another used pm-1200, it seems to work nicely but the fans are not stable, by not stable i mean that they operate slowly on normal setting and are irratic on high speed, (spining slow to FAST), this amp has been fitted with the new service bulletins, new pcb with 4 caps, so i was wondering where should i start to look to solve my problem, Thanks...
BTW : this amp was on all the time, and was in a heavy smoke environment, so the interior is all coated with this greasy residue....so i don't know if this can affect something
BTW : this amp was on all the time, and was in a heavy smoke environment, so the interior is all coated with this greasy residue....so i don't know if this can affect something
Hi mrshow4u,
The problem is simpler than that. Carver used thermal cutouts, not linear sensors and the fans run off their own unregulated supply (HINT!)
Hi pjaneiro,
I've replaced a ton of fans over the years. Right now, use a touch of Methyl Hydrate on the shaft of the fans as they clear the bearing. I'm trying to wash out the smoke residue. After you've cleaned out the residue, use a light weight (single weight, NOT 3 'n1 or anything like that) machine oil and lubricate the bearings. Turn the shafts only by hand, do not run the amp yet! Once they are turning freely with a touch of excess oil around the bearing, you can turn the amp on. You should be able to clearly feel the poles as you rotote the shafts.
The fans were normally wired in series. One stops and the other turns faster.
If the supplies in your amplifier are unstable, the fans will also do as you describe. Fix that problem first.
-Chris
The problem is simpler than that. Carver used thermal cutouts, not linear sensors and the fans run off their own unregulated supply (HINT!)
Hi pjaneiro,
I've replaced a ton of fans over the years. Right now, use a touch of Methyl Hydrate on the shaft of the fans as they clear the bearing. I'm trying to wash out the smoke residue. After you've cleaned out the residue, use a light weight (single weight, NOT 3 'n1 or anything like that) machine oil and lubricate the bearings. Turn the shafts only by hand, do not run the amp yet! Once they are turning freely with a touch of excess oil around the bearing, you can turn the amp on. You should be able to clearly feel the poles as you rotote the shafts.
The fans were normally wired in series. One stops and the other turns faster.
If the supplies in your amplifier are unstable, the fans will also do as you describe. Fix that problem first.
-Chris
Hi mrshow4u,
The consumer amps didn't use the fan normally, the cut out was the same. They can be very similar otherwise.
Sometimes the brushes will be shot already, or the bearing seized. Just do what you can.
-Chris
The consumer amps didn't use the fan normally, the cut out was the same. They can be very similar otherwise.
Yep, smoke residue gums them right up. If you just add oil, you end up with a sticky mess that will go further into the bearing. I hold the motor shaft down so the goo runs away from the bearing. You will remove older lubricant also, so this isn't a bad thing. New lube will then extend the motor life.
Sometimes the brushes will be shot already, or the bearing seized. Just do what you can.
-Chris
Thanks guys, i just cleaned both fans, and when i power up them up with an external power source they run nicely, so my problem is probably the voltage supply, i have the schematics, but where should i start, these are beasts to work on, , also i just noticed that my right channel runs a bit higher than my left !, the clipping light even lights up a bit when i play it hard, would the bias need adjusting ? or then again the problem is elsewhere ?
Thanks again for your help...
Thanks again for your help...
Hi pj, I think Chris was saying the fans are in series. That would indicate a mechanical friction difference in the two fans, if they're turning at different speeds. If one amp channel is warmer than the other after just idling for a while, that would indicate a bias/idle current difference between the two channels.
Clipping light might be coming on early? Do you have a way to check at what power level? A ot of clipping circuits turn on when the input to output (minus gain) difference becomes large. This could happen from open emitter resistors, or the commutator transistors not switching the higher B+/B- rails onto the output devices.
Clipping light might be coming on early? Do you have a way to check at what power level? A ot of clipping circuits turn on when the input to output (minus gain) difference becomes large. This could happen from open emitter resistors, or the commutator transistors not switching the higher B+/B- rails onto the output devices.
Hi pjaneiro,
Troubleshooting and repairing Carver amps requires more skill and understanding than I've seen the average repair shop exhibit.
Bias adjustments will not affect this. Do not adjust any controls!
Please take your amplifier to a really good service tech who is used to servicing Carver. Most every tech will tell you they are, look for an older tech that was once Carver warranty. This is the least expensive way to get your amplifier repaired. He probably looks tired and is busy.
The greatest amount of damage I've seen comes from small shops or techs who refuse to admit someting may be beyond them. A "friend" that knows electronics is even scarier second only to an electronics teacher that decides the amp was designed incorrectly. An electronics engineer (now professor) stands alone as the single most destructive force in the universe. Just observations from servicing equipment for a long, long time. Please don't cause harm to your amplifier.
-Chris
Troubleshooting and repairing Carver amps requires more skill and understanding than I've seen the average repair shop exhibit.
Bias adjustments will not affect this. Do not adjust any controls!
Please take your amplifier to a really good service tech who is used to servicing Carver. Most every tech will tell you they are, look for an older tech that was once Carver warranty. This is the least expensive way to get your amplifier repaired. He probably looks tired and is busy.
The greatest amount of damage I've seen comes from small shops or techs who refuse to admit someting may be beyond them. A "friend" that knows electronics is even scarier second only to an electronics teacher that decides the amp was designed incorrectly. An electronics engineer (now professor) stands alone as the single most destructive force in the universe. Just observations from servicing equipment for a long, long time. Please don't cause harm to your amplifier.
-Chris
I admit that I am more used to reparing std amplifier designs like akai's, technics, NAD and such, even some of the older models like the bgw's 750's and 8000's, or the good old Dynaco's...Problem is that there is no Carver service center here in montreal, or if there is or was, well i am unaware of where they are so if anybody knows where i could find a guy here in the montreal region, that would be nice...
Thanks
so if anybody knows where i could find a guy here in the montreal region, that would be nice...Thanks
Hi pjaneiro,
Try to find a good technician if you can, otherwise you may have to look outside your area.
The amount of destruction coming from Quebec was out of proportion to the rest of the country. Some dealers had their service status removed due to dishonesty in billing. Others for incredibly bad workmanship.
Everyone, just a word about warranty claims if you are a warranty shop. Each product has it's own "normal" percentages of service items. When claims are falsely billed, you stand out as being dishonest, or really very stupid. You can tell the good shops from the bad ones very easily. A store's history will stand out as well. There is no beating "the system" in the long run. Distributors talk to each other too, so you kill your reputation over many brands instead of one only.
-Chris
Yes, I know.
Try to find a good technician if you can, otherwise you may have to look outside your area.The amount of destruction coming from Quebec was out of proportion to the rest of the country. Some dealers had their service status removed due to dishonesty in billing. Others for incredibly bad workmanship.
Everyone, just a word about warranty claims if you are a warranty shop. Each product has it's own "normal" percentages of service items. When claims are falsely billed, you stand out as being dishonest, or really very stupid. You can tell the good shops from the bad ones very easily. A store's history will stand out as well. There is no beating "the system" in the long run. Distributors talk to each other too, so you kill your reputation over many brands instead of one only.
-Chris
Hi Pj, This looks like a dead link <http://carverservice.com/ >, but this place is supposed to be the old Carver factory crew. ...including Bob's daughter Laura. I don't know what's up, I thought this link should've been active by now. If you can't find a Carver competent shop in your locale, it might be worth shipping it to Washington state. I'll see how to get in touch with these guy's
Hi mrshow4u,
He doesn't have to go nearly that far away.
I ran the factory warranty shop in Canada for Carver under AC Simmons. We were warranty while Evolution Audio had the line. I had close ties to the engineering dept as well.
We never got along that well with Carver's own service department after the Carver dust settled. Seems they wanted it all, Canada too.
-Chris
He doesn't have to go nearly that far away.
I ran the factory warranty shop in Canada for Carver under AC Simmons. We were warranty while Evolution Audio had the line. I had close ties to the engineering dept as well.
We never got along that well with Carver's own service department after the Carver dust settled. Seems they wanted it all, Canada too.
-Chris
....I think this is another one. The contacts name is Rolland. I think they bought the Carver parts inventory when Sunfire decided not to tsupport Carver anymore.
...I think Carver Pro is still supported by: <http://www.carverpro.com/> Oregon State
...I think Carver Pro is still supported by: <http://www.carverpro.com/> Oregon State
Hi Kanwar,
I have never directly spoken to Bob Carver, but he surrounded himself with very friendly, helpful people.
From what I gather, I doubt we will see Mr. Carver hanging up his "soldering iron" any time soon. Sunfire is his current company. From the press, he is still very much on his game.
Check for Bob Carver's company here.
-Chris
Edit: You know, he is another very interesting person I'd love to meet some day.
I have never directly spoken to Bob Carver, but he surrounded himself with very friendly, helpful people.
From what I gather, I doubt we will see Mr. Carver hanging up his "soldering iron" any time soon. Sunfire is his current company. From the press, he is still very much on his game.
Check for Bob Carver's company here.
-Chris
Edit: You know, he is another very interesting person I'd love to meet some day.
Hi pjaneiro,
I'm all the way in Georgetown, about 5 hours from Montreal if the traffic is good (right!, like that's possible!). Just north west of Toronto.
If you can't find anyone closer I can try to help you out. Mail is good. Don't be like the one person who shipped an amp in a pillow case though. No stuffing, packing or protection, just the amp inside a pillow case. It didn't survive.
-Chris
Edit:
Hi Kanwar,
There are so many people I'd like to meet. Mr. Pass for one. There are others. Everyone I have met so far has been both kind and interesting. Discounting a couple people who were very full of themselves that is. I will not mention any names as it isn't fair to them.
I have some, the beard is going gray too! I'm too young for this!!!
I'm all the way in Georgetown, about 5 hours from Montreal if the traffic is good (right!, like that's possible!). Just north west of Toronto.
If you can't find anyone closer I can try to help you out. Mail is good. Don't be like the one person who shipped an amp in a pillow case though. No stuffing, packing or protection, just the amp inside a pillow case. It didn't survive.
-Chris
Edit:
Hi Kanwar,
There are so many people I'd like to meet. Mr. Pass for one. There are others. Everyone I have met so far has been both kind and interesting. Discounting a couple people who were very full of themselves that is. I will not mention any names as it isn't fair to them.
Ahhh, too young...ok..... , Ok, Send me a PM, and if i can't find anyone competent enough to service this baby, i'll gladly send it over in a 4x4 wooden crate filled with packaging pop-corn Just the shipping would be enough to pay the amp twice over...I've read that Carver also sold input boards that replaced the TRS and XLR for unbalanced RCA jacks, like in in the M 1.5T
, Ok, Send me a PM, and if i can't find anyone competent enough to service this baby, i'll gladly send it over in a 4x4 wooden crate filled with packaging pop-corn Just the shipping would be enough to pay the amp twice over...I've read that Carver also sold input boards that replaced the TRS and XLR for unbalanced RCA jacks, like in in the M 1.5T- Status
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