Akai AT-27 tuner - FM Auto/Mono not working

[qwer1304]

Hi qwer1304,
That's very good news. That amount of offset in the detector would throw everything off. Now that you have that adjustment tamed you can very carefully try the others you have tried to see if everything else comes into alignment. Very slow motion with the tool and a little care might help. Try working with a weak station as these will respond more strongly to a small adjustment.

-Chris

The other adjustment mentioned is SR101, albeit with a weak station. Will do.

What about the drift it station position of 100 kHz? How do I address that?
(It's actually down 100 kHz, i.e. I have to tune to a frequency 100 kHz LESS than the official frequency and this happens on ALL stations)

Thx

 

[ej25awd]

Success!

Opened the AT-27L today:
1.There's a testpoint TP8 not in the schematics on the other side of R121, so measuring was simple.
2.The discriminator was WAY off (about 4V). After tuning T102 it's imperceptibly (with my DVM) close to 0V and stereo detection is back.

Thx

PS Some stations are still off by ~100KHz. Any way to recalibrate this?

David,

Are you using "Auto Tuning" by any chance when you adjusted T102? Do not rely on this feature, they don't always work. Turn off the "Auto Tuning" and manually tune to a strong FM station closest to 98MHz, re-adjust T102 then go from there.

BTW, where are you located?

- Jov

 

[anatech]

Good thought Jov.

It's difficult to advise someone on what to do with a repair simply because there are all these little things we do without thinking ourselves. It's easy to miss these minor details that can make such a huge difference.

-Chris

 

[qwer1304]

David,

Are you using "Auto Tuning" by any chance when you adjusted T102? Do not rely on this feature, they don't always work. Turn off the "Auto Tuning" and manually tune to a strong FM station closest to 98MHz, re-adjust T102 then go from there.

BTW, where are you located?

- Jov

Success!
I have a strong 97.8MHz station nearby, so I manually tuned to it and redjusted T102 to give almost 0V reading. Interestingly, all other stations are now tuned at their nominal frequencies.

Thx very much for the help and for staying up with me!
David

PS I'm in Israel

 

[ej25awd]

Success!
I have a strong 97.8MHz station nearby, so I manually tuned to it and redjusted T102 to give almost 0V reading. Interestingly, all other stations are now tuned at their nominal frequencies.

Thx very much for the help and for staying up with me!
David

PS I'm in Israel

David,

I'm glad it worked out for you.

Cheers!

Jov

 

[anatech]

Hi David,
ll is right with the world then. You fixed your first tuner ...

-Chris