• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Sansui 7900z FM tuner help

W

westfallian

New Member
I have a Sansui 7900z that I've been trying to get the tuner working properly. So basically the tuner works on mono and I have good signal on many stations, but the 'Tune' level wont center properly so on an auto scan most all real stations get ignored and it will stop on some in-between station where I'm picking up two different stations but one on each speaker. What I've tried to far is adjusting the 'VR1' VCO adjustment pot but there is absolutely no change. I've also adjusted the 'VR4' stereo muting pot and that seems to be working okay. At this point I feel like it's probably some bad capacitors on the VCO side of things. If anyone has any advice or knows exactly which capacitors to inspect let me know! Thanks for the help.
 
Register to hide this ad
It sounds like the discriminator is slightly out of alignment. Hopefully you marked the VCO and VR4 pots before you moved them and now have them back where you started.
try tuning to a strong station, and peak the signal meter, but dont worry about the center tune meter,
Now you will need a nylon alignment tool as anything else metal will detune the transformer or damage the ferrite slug. Listening with headphones and with the proper tool adjust first DT2 and then if necessary DT3 slightly. One of the adjustments will move the center tune into the middle rapidly. Set it for center, and your stereo light may come on. The other adjustment may decrease volume level so it it does, bring it back to peak point or where you started. If this still doesn't bring on the stereo light, try going back to the vco adjustment, noting where you start, and then go CCw and then CW leaving the adjustment in the middle from where the light comes on and goes off on both sides (basically midpoint of the light on)
Good luck
 
Tom B said:
It sounds like the discriminator is slightly out of alignment. Hopefully you marked the VCO and VR4 pots before you moved them and now have them back where you started.
try tuning to a strong station, and peak the signal meter, but dont worry about the center tune meter,
Now you will need a nylon alignment tool as anything else metal will detune the transformer or damage the ferrite slug. Listening with headphones and with the proper tool adjust first DT2 and then if necessary DT3 slightly. One of the adjustments will move the center tune into the middle rapidly. Set it for center, and your stereo light may come on. The other adjustment may decrease volume level so it it does, bring it back to peak point or where you started. If this still doesn't bring on the stereo light, try going back to the vco adjustment, noting where you start, and then go CCw and then CW leaving the adjustment in the middle from where the light comes on and goes off on both sides (basically midpoint of the light on)
Good luck
Click to expand...

Okay I’ll give that a shot. I made sure to take a picture of everything before I adjusted. I guess I should have actually marked it but I’m pretty certain I’m back where I started. I’ll check back shortly with the results. Thanks.
 
Thanks Tom B the dT2 adjustment got me back to center tune and I have stereo! Sounds like there is a just a little bit of static when stereo is selected, but otherwise I’m glad to have the tuner working properly. Thanks again!
 
Tom B said:
Great news. I like when I can help with a repair long distance!![/QU

Sorry to hijack this thread. I have a Concept 5.5 who pulls in strong fm signals and sounds increadible but I can't get the stereo light to turn on. The audio is in mono and the mono switch is not depressed. FM muting works and stations do come across clearly but again no stereo sound. I read above about VCO, DT2 and DT3 adjustments. Can you please help me identify those points of adjustment please? I know where to do TCA, TCR and TCO adjustments, are these the same? Thank you.

459114-concept_55_receiver.jpg
Click to expand...
 
You must log in or register to reply here.
Back
Top Bottom