Nakamichi TA4A Tuner Issues

[ZeroG]

Greetings and Happy New Year to All!

The tuner on my Nak TA4A was not functioning, and with Mooly's kind help on a voltage supply issue it now works. Of course, now that it works some other tuner issues have now become evident.

One is that the tuner won't auto-tune. Early on I was given the advice to adjust L305 to 0.0V at TP-1 on the tuner board in the event that was causing the tuner issue. Unfortunately it won't adjust fully, and BTW, it's a two-pin test point. It does adjust down to 1.07V on one pin and the other measures 6.25V. If tested while shorted together they measure 6.25V.

The troublesome part of the auto-tune not working is that when the auto-tune button is pressed, there is a decent sized pop sound (similar to speaker turn-on with no relay) heard from the speakers, and the tuner mutes fully. When the button is pressed again, the tuner unmutes and the pop sound is heard again. The tuner display also runs up and down the 'dial', (and the signal strength meter changes as it does) but does not lock in on any station.

I understand that FM muting would probably kick on during the auto-tune, but I'm wondering if that pop is normal. I would think it isn't. It doesn't happen on AM, only on FM. Also, when a station memory button is pressed, the auto-tune lights up and when it is turned off, the pop sound is again made.

I've re-checked all the ribbon cables which had to be removed and reinstalled every time the control board had to come out, and they are all now fine.

Much appreciated if anyone could shed any light on this...

[ZeroG]

I tried adjusting the L305 again, this time got it really close to spec - and the popping issue stopped and the auto mode works!

I'm amazed, thrilled, and relieved!

[ZeroG]

OK, well it works. And I'm grateful for that!

But, now that I've set several station pre-sets, I find that it makes a skidding noise (like the sound of passing the stations on a dial that was rapidly twirled) before it settles in on the station that was pre-set.

This seems odd - should just go directly to the station, right?

Must be an adjustment to something. Anyone know what it would be?

Thanks, and HNY!