Hi Folks,

I have a Yamaha RX-V630RDS tuner amp, multi channel DSP.
The problem is confined to the tuner module.
I have negligible knowledge about electronics but can use test equipment and soldering kit.

The problem is that this unit self-tunes, but the sound is "off", like when you tune an ordinary radio and get the tuning slightly adrift of the ideal setting. You've turned the tuning dial a bit too far left or right of the ideal, if you follow me.
This fault is present on both AM and FM.
When I plug a separate radio into another input, the sound output through the unit is perfect.

I took the tuner out, dismantled the casing, cleaned everything with alcohol and put it back. No change.
It's a Mitsumi and seems long obsolete. Ebay and suchlike don't list anything.
9 V7424200 AM/FM TUNER FAE350-J10F J ＡＭ／ＦＭ チ ュ ー ナ 13
* 9 V7424300 AM/FM TUNER FAE350-A10F UCRTK ＡＭ／ＦＭ チ ュ ー ナ
* 9 V7424400 AM/FM TUNER FAE404-E10F ABGL ＡＭ／ＦＭ チ ュ ー ナ

I have the service manual on pdf but this forum says it's too large to post here.

I see the tuner has various "pots" inside with what looks like crosses on top that I could use a screwdriver to adjust, but i can't see any guidance on which does what and would quickly mess the settings up.

Any thoughts, please?

 

Yes. Don’t make any adjustments.
Let‘s wait until we get a chance to look into this.

 

I have the service manual on pdf but this forum says it's too large to post here.

You could try 'zipping' it to see if it gets small enough to post.

 

Yes. Don’t make any adjustments.
Let‘s wait until we get a chance to look into this.

Thank you.
I should add that the RDS functions work perfectly, text scrolling etc. It "knows" what station it's tuned to but just isn't tuned properly.

 

You could try 'zipping' it to see if it gets small enough to post.

 

Here is the weblink address for the manual:

https://www.vintageshifi.com/repert...e.php?pdf=Yamaha-DSPAX-630-Service-Manual.pdf