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Left channel fades with turntable use

1707 Views 4 Replies 4 Participants Last post by Sticklyman, Jul 25, 2009

Sticklyman

Discussion Starter · Jul 24, 2009

I recently bought a Technics SL-BD1 turntable, and SA-303 receiver from ebay, they're quite nice for the most part, but I am having a problem. When I use the turntable, my left channel slowly fades out until nothing but the pops and other junk noise from the record are coming through the left, no music. If I unplug the RCA cable and put it back in, sound comes back, then fades again. What's worse is that if I use the turntable, and then switch to a different input, say one of the two tape monitors which I have my computer hooked up to, left channel is still gone and wont return until I have both the turntable and receiver off.

I'm hoping that this somehow has something to do with the input jacks being dirty (they look kind of grimy and a bit oxidized), but the fact that left stays gone after I switch makes me think it might be something else. Any help would be appreciated.

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Denophile

· #2 · Jul 24, 2009

try plugging the tt to a different input--it will be soft but you should be able to hear if it still happens if you turn it up.

if still there--most likely the tt/cable/cart--not sure if the cart can be replaced on that model or not--alternately make sure the pins on the back of the cartridge are snug but the output cable could be bad as well. given the issue my guess would be the cartridge or the connection to the cable behind it. let us know how it works out. good luck

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Gizmologist

· #3 · Jul 25, 2009

Does the audio on the affected channel smoothly down fade or begin to crackle and then fade out?

Try another source such as the receiver or a tape deck. Does the system work correctly or do you get the same effect? If the effect is the same for all sources, and the signal crackles as it disappears, the problem is quite likely the power amp section. Depending on the circuit design of that unit it could be all in one IC or discreet output transistors.

I am not familiar with the specifics on your particular unit, but what you are describing is quite common of a blown output.

If you want you can test this yourself fairly easily. All you need to do is remove the cover, power the unit up and apply an input signal. Take a can of Dustoff from an office supply store and invert it. Look for the wires from the speaker terminals and follow them back to the board. Once you locate the output board, spray the largest ICs with the spray until, they frost over. (just a couple seconds) The defective part will usually come back on and sound relatively normal or crackle and go out completely. A good IC will not change sound output as it is cooled.

This is a basic test and not completely solid proof of the location of the problem but it usually is a good indicator.

Be careful not to touch any circuitry with your fingers OR the can.

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mcnarus

· #4 · Jul 25, 2009

Try switching channels: Plug left into right and vice versa. This will tell you if the problem is at the turntable end or the amp end.

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Sticklyman

Discussion Starter · #5 · Jul 25, 2009

Quote:
Originally Posted by Gizmologist /forum/post/16883951

Try another source such as the receiver or a tape deck. Does the system work correctly or do you get the same effect? If the effect is the same for all sources, and the signal crackles as it disappears, the problem is quite likely the power amp section. Depending on the circuit design of that unit it could be all in one IC or discreet output transistors.

Left channel only fades out when I use the turntable, but then stays gone if I switch to another input, unless I have the turntable off and the turn the receiver off and on again. Usually sound comes back if I just work the power switch, without waiting for the unit to fully power down and stop producing sound.

Also, mcnarus, that's a brilliant idea, I should've thought of that. Sadly, I'm in the process of slowly moving, and wont be at the residence with my stereo for probably a week.

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