Hey there DIY'ers. I recently bought an old Akai AM 2200 from a pawn shop here in Whitehorse, Yukon Territory. After plugging it in I was dissapointed to hear lower output and distortion in the right channel. After looking inside I noticed one of the 4 fuses looked faulty. I removed it, drove into town, bought 4 new fuses, drove back and replaced the faulty fuse. I then plugged it back in only to discover the same right channel distortion. I then rechecked the fuse i had just replaced, it was still good... I then noticed that the fuse that was faulty to begin with had a different rating then the others. I guess someone had already blew and replaced said fuse. Not wanting to drive back into town I replaced all the old fuses with identical new fuses. To my amazement, no distortion.
Old fuses: 3 x 2A, 125V ac and 1 faulty 2a, 250V ac
New fuses: 4 x 2A, 250V ac
Although both speakers sound good now I get the same right channel distortion when pushing the a and b speaker set button. The switch seems faulty to me but I was wondering if their could be an underlying problem. Any ideas?
I'm a little new to all this with a somewhat limited knowledge in electronics. But living up north can make you start opening things up as help can be hard to find. Glad I found this site with such knowledgeable pros willing to give sound advice. And with that horrible pun, i'm out.
Old fuses: 3 x 2A, 125V ac and 1 faulty 2a, 250V ac
New fuses: 4 x 2A, 250V ac
Although both speakers sound good now I get the same right channel distortion when pushing the a and b speaker set button. The switch seems faulty to me but I was wondering if their could be an underlying problem. Any ideas?
I'm a little new to all this with a somewhat limited knowledge in electronics. But living up north can make you start opening things up as help can be hard to find. Glad I found this site with such knowledgeable pros willing to give sound advice. And with that horrible pun, i'm out.
I found schematics in an older thread on-site. Similar problem too, I think I might start checking transistors...
http://www.diyaudio.com/forums/solid-state/210249-akai-am-2200-distortion-output.html
http://www.diyaudio.com/forums/solid-state/210249-akai-am-2200-distortion-output.html
On older kit things like fuse holders can become tarnished and make poor connections, same for any moving switches and contacts.
Voltage wise the important check is that the voltage on the speaker output is zero volts DC.
If the amp works OK with the speakers connected but distorts when you start pushing the A-B buttons then I would be looking at the switch area/soldering/dirty contacts before going in too deep.
Voltage wise the important check is that the voltage on the speaker output is zero volts DC.
If the amp works OK with the speakers connected but distorts when you start pushing the A-B buttons then I would be looking at the switch area/soldering/dirty contacts before going in too deep.
guys ...here we talk about an amplifier that is 30+ years old expect most electrolytics to be blown specific amp also has some of them placed vertically ( even worst )
Real problem is that outputs are obsolete but 4 drills on the heatsink will easily accommodate a 1934-5200 combo .
Expect most of switches pots and so on to be really dirty and cleaning will be required plus that these amps have a history on failing in the secondary power supply that feeds LTP ( that will be TR 4 and TR 5 together with the related capacitors ) also these are drop in replacements with BD 139-140 combo ( mind the pins though )
Kind regards
Sakis
( e mail me i f you need a schematic )
Real problem is that outputs are obsolete but 4 drills on the heatsink will easily accommodate a 1934-5200 combo .
Expect most of switches pots and so on to be really dirty and cleaning will be required plus that these amps have a history on failing in the secondary power supply that feeds LTP ( that will be TR 4 and TR 5 together with the related capacitors ) also these are drop in replacements with BD 139-140 combo ( mind the pins though )
Kind regards
Sakis
( e mail me i f you need a schematic )
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