Nakamichi TA-3A bad right channel

[Sonic Womb]

I tried searching the forums but couldn't find anything, and a google search didn't turn anything up either. I have a Nakamichi TA-3A that I'd hate to get rid of, but so far no repair shop can help me. It has a bad right channel, no sound whatsoever, but the left channel works fine. I've taken it into several repair shops, but the car ride always "fixes" the problem so the shops tell me nothing is wrong. It works for maybe a day once I get it back home before the right channel cuts out again. Another car ride will momentarily fix the problem.

I can do basic electronics repairs, but I don't know enough to even begin troubleshooting a receiver. Can anyone point me in the right direction on this?

[Mooly]

Well that has to be a physical problem... most likely anyhow.

Not familiar with the model itself... is it an integrated amp ? If so is the problem on any input ? Headphones OK ? or not.

This will be a case of looking over all the PCB's and perhaps just doing a reflow on all joints if you can't find anything specific. It could even be something like a dodgy relay (speaker relay).

If you can get it to go faulty then a careful prod with an insulated tool on the PCB's may help reveal the issue.

If you get it in the faulty state I would do some basic checks like measuring DC offset on the bad channel... it may just be something that is tripping the protection circuits.

You have to start somewhere on a fault like this and narrow things down to see where it leads

[Sonic Womb]

Yeah, this one has an integrated amp. I think it's only the amplified speaker output that is bad, the preamp outputs work fine, but I will have to check the headphone jack this evening. I'll post my findings on your other suggestions this evening as well, thanks.

[Nrik]

I agree with Mooly.

1) If you have sound in headphones but not in the speaker, then it is most likely the relay.
2) Reheat all solderjoints - that can do wonders - I just 'repaired' a Thule amplifier that way.
3) Still problems: Measure DC in the wrong channel - measure on the emitter of an output transistor. If there are separate realys to each channel the protection circuit is protecting your speaker. If there is only one common relay, then this is not the case.

[sakis]

sorry to be a killjoy but for this type of amplifier beyond soldering and relay, well mentioned above the amplifier is made of IC that select inputs and outputs inside
failure of these switches is also quiet common

Add to the above that eventhough NAK designs normally sound very well and also made very well it is also rather common that depending on the serial NAk may also put crappy capacitors inside

obviously you need skilled trouble shooting start though from the simple things given above

[b767]

Originally Posted by Sonic Womb

I tried searching the forums but couldn't find anything, and a google search didn't turn anything up either. I have a Nakamichi TA-3A that I'd hate to get rid of, but so far no repair shop can help me. It has a bad right channel, no sound whatsoever, but the left channel works fine. I've taken it into several repair shops, but the car ride always "fixes" the problem so the shops tell me nothing is wrong. It works for maybe a day once I get it back home before the right channel cuts out again. Another car ride will momentarily fix the problem.

I can do basic electronics repairs, but I don't know enough to even begin troubleshooting a receiver. Can anyone point me in the right direction on this?

Hi do you have TA-3A service manual, i am having protection circuit problems. I have service manual, i am attemping to repair for a friend. The three main pcb's are pretty easy to remove, unit is easy to access. I will lookm at manual to see what advice I can help you with.