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Old 27th March 2006, 04:04 PM   #1
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Exclamation Nakamichi TA-2 not powering up

Hello,
I am looking for a little guidance dealing with my Nakamichi TA-2, when I turn it on the power light flashes but never goes steady. I had this issue about 1 1/2 years ago, so I took it in to have it repaired. The tech replaced a 22k resistor which I believe is the only one in there. I took a look around the new resistor and I noticed that a capacitor in the same circuit looks like it's leaking. Right now I'm waiting for a service manual to arrive before I do anything.
I was hoping to find someone that could tell me if I'm going in the right direction. Also, now that I'm tearing it apart I wouldn't mind knowing if there are some other components that could be replaced to improve sound quality (volume control static, capacitors?).
I do not have a background in electrical engineering, but I have taken a digital circuit design class (I'm a CS major) so I'm not totally lost.

Thanks for your help,
Ben Grindy
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Old 27th March 2006, 04:07 PM   #2
anatech is offline anatech  Canada
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Hi Ben,
Replace the 22K resistors in both channels with 1 or 2 watt metal oxide types. If a cap is leaking (not normal), replace it and clean up the fluid.

That should do it for you.

-Chris
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Old 27th March 2006, 04:12 PM   #3
anatech is offline anatech  Canada
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Hi Ben,
While I'm thinking of it, don't go nuts "upgrading" your receiver. It doesn't sound too bad at all (I have one). It uses solid state input switching, the volume control is motorized. On and on. You will end up with a mess if you start changing a whole bunch of stuff.

Your set will never sound like a separate preamp tuner amp combo. It does sound better than most receivers. Reliable beats tweeked every time.

-Chris
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Old 27th March 2006, 10:20 PM   #4
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Chris,
Thanks for your input, I'll post again once I replace the resistors/capacitor.

I do have another question - before it stopped working there was a noticable amount of static in the right channel when the volume was turned past 1/8 or so, what could be happening there? btw, I have been using the TA-2 as a pre-amp mainly with a separate Carver amplifier (the noise is in the pre-amp output).

Thanks again,
Ben
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Old 28th March 2006, 01:59 PM   #5
anatech is offline anatech  Canada
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Hi Ben,
Now that is interesting. Could be a switch contact. Try operating the tone switch. The variable loudness control may be at fault too. I have never had that fault in any Nak receiver.

I am very familiar with both Carver and Nakamichi. I serviced and own both. The Nak has a better sounding amp, so you took me by surprise. They each have their strong points but I must admit that most who like one, dislike the other.

Mine are used in different areas.

-Chris
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Old 28th March 2006, 03:50 PM   #6
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Chris,
I had tried switching the tone switch on/off and adjusting the treble/bass to see if it affected the noise, but it did not make any difference. The variable loudness control had no effect either.

I actually purchased this specific Carver amp because it is bridgeable so I can use it for a subwoofer (I have a separate crossover). Also it has more headroom for powering my C95s, but when listening at low levels I actually prefer the Nakamichi.

I'll keep you posted on the repair.

Ben
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Old 28th March 2006, 03:55 PM   #7
anatech is offline anatech  Canada
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Hi Ben,
Thanks. That makes sense now.

Your distortion may be due to a muting transistor. I think these were 2SC2878, they can not be checked for this except by removal or replacement. These transistors tend to breakdown and cause this symptom. Note that you can not replace these with other transistors. They are designed especially for this use.

-Chris
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Old 30th June 2006, 01:02 AM   #8
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Hi Chris,
I finally got around to replacing the 22k resistors and the muting transistors. Not only does it power up, but the buzz in the right channel is gone! I forgot how nice this receiver sounds.....

As a side note, do you know of any multichannel receivers that produce similar sound? I have a nice center channel waiting to come out of its box again, but nothing to power it with.

Thanks Again,
Ben
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Old 30th June 2006, 01:09 AM   #9
anatech is offline anatech  Canada
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Hi Ben,
I think you're going to have to roll your own there! To be honest, amplifiers and a processor may be your best bet. Don't expect anything like that from a surround receiver.

Sorry for the news. In Europe they still understand 2 channel sound. Marantz is finally waking up again.

-Chris
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