Technics ST-GT650 FM tuning issue

[Captain Jack]

Hi all,

Newbie here, please be gentle.

I recently acquired the above-mentioned radio tuner and I am having a small but annoying issue with it. It will not auto-find or lock FM stations, decode RDS or give me stereo sound.

The signal strength is good and audio is nice and clear (but in mono). AM band works OK - it locks onto stations when using automatic search.

I took a quick look around the main PCB and it looks clean with no cracked joints. There is a service manual floating around but I don't want to start replacing various components nilly-willy on FM side in hope that one of them will resolve the issue. Sadly, no oscilloscope to start probing around 🙁

Any ideas?

Cheers
CJ

 

[DTC1001]

Hi all,

Newbie here, please be gentle.

I recently acquired the above-mentioned radio tuner and I am having a small but annoying issue with it. It will not auto-find or lock FM stations, decode RDS or give me stereo sound.

The signal strength is good and audio is nice and clear (but in mono). AM band works OK - it locks onto stations when using automatic search.

I took a quick look around the main PCB and it looks clean with no cracked joints. There is a service manual floating around but I don't want to start replacing various components nilly-willy on FM side in hope that one of them will resolve the issue. Sadly, no oscilloscope to start probing around 🙁

Any ideas?

Cheers
CJ

Hi,

I think the tuner must be re-aligned. Try to get the service manual. Mostly the FM discriminator are out of range because the aging of electronic parts. T101 is responsible for the alignment. Take a look at the following thread in a german board, Technics Radio ST-GT650 Empfangsproblem, Hifi-Klassiker - HIFI-FORUM. Perhaps You can translate it by gxxgle translate.

Cheers

DTC1001