Freiburg 14 automatic tuning not working

Steph_schmitz · 23. April 2015, 21:28

Hello all,

This stunning radio is working fine excepted the automatic tuning.
I have tested voltage between test points P and Y and with a strong station I get max 2v while I should get 22v. 2v is not enough that's why automatic tuning does not stop on stations.

Ecl80, eabc80 and ebf89 have been tested and are all good.

Ecl80 and eabc80 polarization voltages are also correct.

Do you have an idea what could be the cause of this problem ?

Thanks for your help !

Stéphane

Steph_schmitz · 25. April 2015, 10:32

And this morning another failure appeared : no more FM !
This afternoon I will make begin investigating but if someone has an idea, he is welcome !

Thanks
Stéphane

Peter J · 26. April 2015, 02:07

Hello,
you didn't say what you already did on this radio. Did you replaced any capacitors, measured all plate voltages?
How about C308?

Regards
Piotr

Steph_schmitz · 26. April 2015, 07:20

Hello!

All my excuses for not giving enough details.

Yes I replaced c308 but also c719/c723 (motor caps). And also c709.

I did a number of steps, including injecting 10,7 mhz on the ech81 grid and the eye is wide open. Meaning problem is located before (in the FM tuner most probably).

Can someone tell me the value of L111 ?

Thanks for any help!

Stéphane

Peter J · 26. April 2015, 08:07

You should probably check both EC92, even switch them in their places for starters.
Or it could be some cold joint in the tuner if that doesn't help, but I would rather bet on a faulty tube.

Steph_schmitz · 27. April 2015, 09:07

FM is working again.
I repaired L111 which was faulty.

I measured p-y and I have between 11 and 13v maximum.

It's too low, as I should have 22v.
I will continue investigating.

Thanks,

Stéphane