dr*audio
Fish fingers and custard!
I have a Pioneer SX-727 that I picked up recently that sounds and works great except for the tuner. On strong stations the signal strength will be about 3.5 on the meter, then it will jump to almost 5 and the stereo light will come on. It bounces like this continually, or often it will just hover around 3.5 and remain in mono. I did a basic alignment (don't have a distortion meter so am limited on my tuner alignment capability) and when the meter does jump up the sound is strong and clear.
(Also note that AM does not tune in at all except when the FM signal is strong, then I can quickly switch to AM and some stations will tune in. This usually only lasts for 10-15 seconds though, then the AM signal is gone and switching back to FM the signal has dropped again). I found that rotating the tuner back and forth numerous times will usually cause the FM signal to come in strong for perhaps a minute or less, then it will bounce back and forth or settle back to 3.5. I sprayed the tuner fins with CRC QD contact cleaner, put faderlube on the points noted herein, and it seems to have helped a little, but overall the symptoms still remain. The voltage supply is 12.5 volts and clean so that does not appear to be an issue. Any suggestions would be most appreciated.
I'd also like to thank the contributors to this thread as it is an absolute wealth of information!
The tuner needs cleaning. Spraying the fins does nothing unless they are dusty, and if they are you need to used compressed air, not cleaner. You didn't clean the contact points before you put the Faderlube on them so that didn't work. Go back, re-read the instructions and follow them exactly.