Pioneer SX-4 receiver FM issues

83Hertz

Well-Known Member
The tuner on this receiver doesn't work right, and I don't know where to start...

There are 2 presets that happen to be set for stations that come in fine. They sound clear, but I can't tell if they're coming through in stereo or not. The "tuned" light doesn't light on either station, but does blink while the tuner is scanning. Pressing either "tuning" button causes the receiver to scan in the appropriate direction, but it can't find any stations (not even the two that come in when I select their presets). I have access to the service manual online, but my only test equipment is a decent multimeter. Is there anything I can do with that?

Any suggestions?
 
For what it's worth, I never thought much of the tuners in the early digital Pioneers. How they could produce those "Super Tuner" car stereos and then drop the ball on their home gear ?? I have an SX-6 and only use it like it was an integrated. I have a tuner run in at AUX. IMHO, it takes too much signal to make even a noisy stereo. Try engaging the mono / mute button and tuning it manually. That might get you started. See how it works that way. The two presets were probably the only ones that came in. In mono it should get a lot more. The scan function takes way too much signal on those to unmute. Most of my tuners will get three or more stations without an antenna, the SX-6.. none. By the time they got to BPC, they seemed to have worked it out. I have one of those and it works fine. Never considered making a silk purse out of it, the amp sounds good and I have plenty of tuners that make me smile. It might be fine downtown in a big city but out in the sticks, it's a good amp.
 
Thanks! Just to clarify, with the mono/FM mute off button pushed in I get the two stations (in mono, now I understand what that button does). With the button out, absolutely nothing. There doesn't appear to be a way to manually tune this one, unless there's a trick I'm not aware of. That's why I can only get those two, I'm sure if I could manually tune I could get more stations. For reference my BPC alarm clock I've had since I was a kid pulls in a bunch of stations sitting next to the stereo, so I know there's good signals here... maybe I'll run the headphone jack from the clock into the aux for now, and start looking for an older receiver (because I like the vintage look) with a better tuner...

Thanks again for the info!
 
I had to look for info on an SX-4, I know they are different. The 6 has a digital display of freq and that's different but they both tune the same way, or should... The 6 has a manual tune button (handy) I don't see one on the 4. Mine has been the amp for my bench for years now, PC routed through it too. The memory stop function will freeze the scan but you have to be quick. Too many decent, cheap tuners available to have to bother with it. I use a Yamaha T500. What I'm saying is that you might get it sorted out and find the results pretty dismal. I'll stand on my first assessment, it's a decent amp. It sounds quite good.
 
What I'm saying is that you might get it sorted out and find the results pretty dismal. I'll stand on my first assessment, it's a decent amp. It sounds quite good.

I do like the way it sounds! I don't want to invest a lot of time/money in it just to find out it's never going to be all that good at FM reception though. I'll keep my eyes open for a nice tuner, or perhaps an older receiver that fits my vintage vibe better...
 
antenna ?

Tried several different setups. Had speaker wire strung around several different ways, even found a basic wire dipole, mounted it on the wall close to the ceiling. Tried both the 75 ohm and 300 ohm posts too... the alarm clock, on the other hand, doesn't even have an external antenna, and it pulls in tons of stations loud and clear...
 
IMG_3975.JPG

Something like the little white guy on the right inside the metal shield at the top of the photo? Those posts right above it are the 300 ohm connections...
 
wouldn't harm to mark where it is now and turning a bit with a plastic tool to see if any improvement .. is a shot in the dark though .. has worked for me in the distant past .
 
might need a proper alignment then

I've done tons of alignments- fords, buicks, oldsmobiles, Mazdas, toyotas, hondas, etc. Should I see if our automotive alignment machine will work on my pioneer?

Just a little humor for a Tuesday evening...
 
i primarily fix cars but used to mess about with radios .. am no problem wave a wire in the air to pick it up ..fm is not the same .. need to set the frequency then mess around with it .. its beyond me ..
 
Yeah, I've never really messed with fixing stereos. I've tinkered a little when I was younger, but mostly with bad results...

Went to tech school for auto mechanics, been fixing cars ever since...

As for this receiver, the alarm clock headphone jack feeding the aux inputs seems to be an acceptable work-around for now... don't really want to invest much in the tuner section of this receiver (don't like the lack of manual tuning, and the lack of a decent frequency display) so that means I'm eventually gonna have to find a tuner or upgrade the receiver...
 
If you have reasonably strong stereo broadcast stations near 90 MHz and near 106 MHz in your area, page 23 of the service manual has instructions for setting many of the tuner functions with only a voltmeter - No other special equipment.
 
If you have reasonably strong stereo broadcast stations near 90 MHz and near 106 MHz in your area, page 23 of the service manual has instructions for setting many of the tuner functions with only a voltmeter - No other special equipment.

Oooh, I will have to give it a try... thanks!
 
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