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Pioneer sx-1010 recent problem with Fm playing in stereo

lopezluna

lopezluna

Active Member
Good morning fellow AK'ers. I purchased a pioneer sx-1010 receiver on the auction site last month. Everything was working good, fm stereo would come in very good even when signal wasn't very strong. Just a few days ago I noticed that when playing fm it comes in and out of stereo mode even with a strong signal. Also when I change stations it takes a while for fm to come in stereo (with a strong signal) if it even does and it doesn't sound very good. Sounds a bit distorted. When I put it in mono the sound is nice and clear. Any idea what can be the problem here? When first I brought it home (local pickup) I removed the top and bottom covers and did a visual inspection before I put it on dim bulb tester and that tested out good. I have cleaned the selector switches with deoxit d5 and followed with deoxit f5. Everything under the hood looks to be all original. Made March 1974. All was good for a few weeks until a few days ago. Any ideas on what may be causing fm stero to not be functioning properly or what to look for? Any help would be greatly appreciated, Thanks lopezluna
 
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There is no mention of the antenna. Is it a 300 ohm balanced line or 75 ohm coax? How are the antenna connections? Are they clean? Have you tried a different one?

If that checks out OK, then the pilot tone alignment or the IF (intermediate frequency) alignment may have drifted. If the pilot tone is slightly off, the receiver will go in and out of stereo. That 19khz pilot tone triggers the receiver to process the stereo info. If the IF is off, then mono will suffer and forget about stereo. In either case, it will need a FM alignment.
 
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whirligig said:
There is no mention of the antenna. Is it a 300 ohm balanced line or 75 ohm coax? How are the antenna connections? Are they clean? Have you tried a different one?

If that checks out OK, then the pilot tone alignment or the IF (intermediate frequency) alignment may have drifted. If the pilot tone is slightly off, the receiver will go in and out of stereo. That 19khz pilot tone triggers the receiver to process the stereo info. If the IF is off, then mono will suffer and forget about stereo. In either case, it will need a FM alignment.
Click to expand...
whirligig said:
There is no mention of the antenna. Is it a 300 ohm balanced line or 75 ohm coax? How are the antenna connections? Are they clean? Have you tried a different one?

If that checks out OK, then the pilot tone alignment or the IF (intermediate frequency) alignment may have drifted. If the pilot tone is slightly off, the receiver will go in and out of stereo. That 19khz pilot tone triggers the receiver to process the stereo info. If the IF is off, then mono will suffer and forget about stereo. In either case, it will need a FM alignment.
Click to expand...
I was first using a dipole antenna. I read some threads on this forum and did make a adjustment to vr2 19khz pilot frequency and also adjusted T1 to center the tuning meter. All is good now. Thank you very much
 
zebulon1 said:
And - What happens when you use the FM mute "Off" when tuning through the dial?
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Zebulon1 my tuner is working good again. Fm mute off or on made no difference. I was about to contact you to see if you could do a allignment to it. I did read some threads here and did two adjustments. One for to center the tuning meter and the other to adjust 19khz pilot. I then confirmed on test point It was 19khz. All is good now, well as good as its going to be without a full allignment. I am going to do a full restoration on this receiver this week all except the allignment to tuner. Thank you zebulon1, I read and learn lots from you
 
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