Carver PM-1.5 Amp Help

Hi everyone, Its a stereo amp thats supposed to deliver 450W rms per channel into 8ohms.

One channel (right) is very quiet but I can just hear it through the speaker I have attached, the second channel is louder but not by much :( Im assuming the amp is blown somwehere, does anyone know any common faults that would cause this in this particular model amp or have any idea where I should actually be looking? I can provide photos if that will help.

Also would anybody have a schematic diagram for this?

Cheers!

Reply to
bytraper
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bytraper: Get your DMM out and take voltage measurements in the power supply and make some component tests, primarily the semiconductors, low ohm resistors and electrolytics in the audio power output/driver stages. Also, be certain that you have not forgotten to jumper the preamp out/main in connections if there are any..... and make sure that all the switches are in the correct position and a tape monitor or adaptor switch is not left on. The good news is that because a stereo amplifier has duplicate circuitry in the Left and Right channels you can easily make circuitry comparisons. It would be unusual that BOTH channels would have exactly the same failures so be certain to look at the things that both channels have in common like the power supply and the switch positions, etc. electricitym . .

Reply to
electricitym

snipped-for-privacy@yahoo.com wrote: : bytraper:

: The good news is that because a stereo amplifier has duplicate : circuitry in the Left and Right channels you can easily make circuitry : comparisons. It would be unusual that BOTH channels would have : exactly the same failures so be certain to look at the things that both : channels have in common like the power supply and the switch positions,

The bad news is the Carver stuff from that era didn't use conventional designs and the above would probably not apply.

Most of his amps were rated from 350 to 600 watts rms but the heaviest of them was probably around only 20 pounds. The power supplies in those were very unusual (named magnetic field) compared to standard amps and likely the problem with the amp is related to that.

Although hunt and peck might work, this is really one peice of hardware one should have the manual on, at least the schematic to examine the power supply portion of it. The "grounds" on those amps should be particularly noted. It's not a hot chassis like modern day tv's are but the rail voltages (from memory) aren't taken from what you think is ground. More of a reference voltage from that triac thing to other points.

Anyway, scout around ebay, there is usually a guy on there selling the manuals for those things. Probably photocopies but should be under $10.

Note that these amps had dozen of circuit mods made to them at the factory and chances are none of the "factory" schematics show them. Also I haven't checked recently but parts for the exotic stuff were next to impossible to get even just 5-6 years ago. Think Bob Carver started up his own company called Sunfire after selling "Carver" to some investment firm.

Good luck with it, you found a real challenge there.

-bruce snipped-for-privacy@ripco.com

Reply to
Bruce Esquibel

I would just recommend getting a specialist to repair it. Carvers are pretty "special". I have seen bad solder at an input coupling cap on one of these, though.

Mark Z.

Reply to
Mark D. Zacharias

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