Screaming Yamaha P2200 Question

[HazenK]

Aloha All,

I've had this P2200 for about 12 years now, bought it for $350 off an old studio grunger back in my early college days when i had a hard time scraping quarters together for malt liqour.

I've used it to power subs, main, guitar amps, whatever. It's always been great, though it was ugly when i got it. I am an unknowledgeable person when it comes to circuit boards and components. I know sound and can solder a connection.

Today in the middle of a song one channel just started putting out a god awful screaming sound. It was a steady whine coming oput of the full range tower. The air filled with the smell of ozone as i flipped off the amp. It seemed appropriate that my friend had been recalling her first time seeing the "Exorcist".

I checked the speaker against the other channel, no problem. I checked the input against the good channel, no problem. I was using and old Yamaha reciever to output to the amp from a computer source. My first thought was digital distortion. Nope. It's the amp, right channel. Whenever i tried to hook up anything to that channel, with the level set @ 0 or full, it would arc the speaker leads, and then (i am assuming) arc inside the speaker box. The ozone emanating form the ports makes me think as such, undoubtably not great for my speakers.

This being rural Hawaii I immediately thought a gecko might have bridged some gap inside the amp, or maybe another ants nest had manifested itself into being inside a cherished electronic component. (don't even ask about past experiences with computer PSU's or printers.) Upon taking everything apart I was loathe to find any discernible organic interference, or obviously smoked components. This unit had been worked on in the past, god knows by whom and at what level of competence. It has an open top with minimal grilling. I've only ever needed to solder in a new VU bulb. That channel's meter always read a little higher, but i figured it was just a calibration thing. It's been a great friend and i'd love to fix er' up.

To my knowledge there is no one on this island who might fix this that i trust. We are an extremely rural island and most fixes involve removing damaged parts and bypassing them or outright replacement. It wouldn't surprise me to find out that one of teh original designers or testers of this unit lived here, but hell if i'd know how to contact them.

So sorry to be so long-winded, i hope this is an easy fix, an immensely noob question and that we can all praise the genius who lambaste's me for my ignorance. Otherwise this venerable unit may be relegated Craigslist and some goofball who need a one channel amp.

Mahalo,

Hazen

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About P2200
P2200, Yamaha’s first professional power amplifier was introduced in 1976. With an output power of 240W per channel, the P2200 started Yamaha amplifiers’ tradition of excellence in sound and well thought out design. P2200’s design allowed access to the inside of the amplifier via the front panel. This design made maintenance and exchange of components parts possible without taking the amplifier out of the rack in case of failures. Uncoated binding posts　were used on speaker output terminals to improve sonic quality. P2200 was replaced with the introduction of PC2002 in 1982, which soon became a global standard in professional amplifiers.

http://www.eserviceinfo.com/download...ha_p-2200.html
http://www.eserviceinfo.com/download...AHA_P2200.html

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