Nakamichi TA-2 Receiver in a funk

switching via a microprocessor (can also be remote controlled). The button lights don't work, and I get no input connections at all. Strange, but the micro works, controlling the volume up and down. Also, the amp works via the pre-out and power-in jumpers. Apparently, some aspect of the switching (done via an analog switch IC) is screwed up. Anyone have ideas on how to troubleshoot this?

I would first check the electrolytic caps in the power supply. Noise on the B+ lines will cause all matter of digital problems with this model. Chuck

What ident is the big an. sw. ?

snipped-for-privacy@googlegroups.com... I'm trying to troubleshoot a 1980'2 era Nak receiver that has pushbutton input switching via a microprocessor (can also be remote controlled). The button lights don't work, and I get no input co nnections at all. Strange, but the micro works, controlling the volume up a nd down. Also, the amp works via the pre-out and power-in jumpers. Apparent ly, some aspect of the switching (done via an analog switch IC) is screwed up. Anyone have ideas on how to troubleshoot this? What ident is the big an . sw. ?

There should be a switching IC (LCxx22 or TC9163) located on the board. In many cases this is the problem. You will see the signal entering the IC, but no output. I believe that the light and the audio are controlled by th e same line. The few of these I have seen in the past were quick fixes by replacing the switching IC. (IIRC)

Dan

Did Nakamichi do the thing with the button lights that they did on some other units? (The lights were used as the pullup resistors in the matrix scanned keyboard or something strange like that).

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

I was able to download a service manual from Elektrotanya.

The site is difficult to access if you don't speak Hungarian but I can email you the manual.

email me at:

mark snipped-for-privacy@labolgcbs.net

and reverse "labolgcbs" to read "sbcglobal".

Mark Z.

On Tue, 15 Jan 2013 06:50:24 -0800 (PST), j put finger to keyboard and composed:

- Franc Zabkar