Kenwood receiver no sound on FM source

All sorts of things... Bad selector switch. Broken leads. Bad FM front end. Shorted FM IF transformer.

Do the other functions sound the same after your speaker experiment? If so the loss of FM audio and the experiment are purely coincidental.

Do you have any experience in troubleshooting/repair of home electronics? Do you have test equipment? You'll need a print, DVM and possibly a cheap scope to fix this one.

I do have a certain knowledge in pinball system board repair. So I guess this is more or less the same. I have a dvm and a test probe.

All other 'sources' like CD and AM radio sound very good. only fm sound output 'disappeared'. the sound stopped while connecting the second pair of speakers (in parallel) to the red and black speaker crimps.

Thanks for any help

A print would be useful to track down where the audio signal stops. A high impedance audio test probe could probably be substituted for a scope.

Hmmm... I guess it will not be an easy fix then?

Hooking up speakers would not cause the FM problem. Could have blown an amp channel, but then the other sources would not work.

Maybe knocked off the antenna, or as someone else suggested, the current lack of FM could be a coincidence.

Mark Z.

Hit the FM stereo switch, set it to mono. Do you get any sound now? When set to stereo the circuit is designed to mute any audio if the quality and strength of the signal being received is'nt stereo worthy ( better antenna/ orientation required). Your RDS is working , else i'd suspect FM detector transformer. Loading 2 pairs of speakers on would'nt cause this problem , as the rest have stated. Jango.

That answer resonates with me, as well, OP. Go back and *carefully* check the antenna connection. If it looks good, unhook it anyway, and hook it up again. You'll have to do it anyway if you repair/replace the receiver, and it's a lot cheaper than those options.

Also, the advice in the thread about switching the FM mode is sound. That might lead you to the same place; a bad antenna connection.

jak

Easy is a conditional term. Easy for an experienced tech with basic test equipment. Not so easy for an inexperienced tech without a print.

The OP says the receiver is getting the RDS display of the channels and the current aired song.

Hi again, I tested some more. Jango was right in that it has something to do with the fm signal being muted whenever it does not receive full stereo fm. The "stereo" on the display does not light. I once managed to quickly receive stereo and I heared the sound. But, I placed the receiver on different locations and it seems that I never can receive stereo fm for any length of time, which results in the muted sound. It's a kenwood KRA-4060 and I cannot find a "mono" button on the receiver or remote control to disable this "muting" behavior. I think there must be something broken on the FM receiver because it never receives in stereo, although it can always receive full RDS signal and a lot of different channels. I think when it can receive full RDS for a certain channel that the reception must be good enough to also receive stereo, not? Also the "tuned" light is on which indicates good reception. It auto-tunes to a lot of different channels. Only never in "stereo" and because it mutes the sound on mono, I have no sound at all. I tried a different antenna but still no luck. I really think the reception is good enough but somehow the "stereo reception" seems to be malfunctioning. I have a cheap small tower receiver as well on the same location and this does receive a stereo fm signal. It's stupid that it mutes all sound to the speaker when it does not receive stereo... Even more stupid is the fact that I cannot seem to change this behavior...

Yeah, I know. What I don't know (don't have any receivers with this feature) is whether the signal threshold for RDS is higher, lower, or the same as for muting. In his latest post, he seems to be having issues with multiplex threshold as well...leading to antenna diagnosis again.

jak

Ollie, can you look at the receiver and describe the antenna terminals? What is hooked to them? If nothing, that's *very* likely your problem. If 'something', disconnect it. Hook it up again and see if your problem still exhibits.

It was working until you messed around back there. It's easy to knock something loose...which upon casual inspection still 'looks' good. In the case of no antenna at all, you may have only had very marginal reception in the first place (just above the muting threshold), and adding/moving wires took the signal level to just below that point.

Check the antenna.

jak

"It started when I tried to hook up 2 speakers per channel instead of one. "

Do you think you might have shifted a tiny slider switch behind the unit , close to the speaker terminals?. Maybe thats where the mono stereo switch is located in this model. Jango.

This is beginning to sound more like a discriminator alignment issue to me. Very common with digital tuners. A surround model might have the discriminator buried in a module, however...

Mark Z.

Well, I previously only used this receiver for CD/Tape playback. I never used the antenna and FM tuner. I connected those T-shaped FM wire antenna's. Maybe these are not strong enough? Also, on the antenna input terminal there is written "75ohm". Does this need the antenna itself need to be 75ohm? Maybe these T-shaped wire antenna's are not 75 ohm?

Stupid question... Was the FM actually working before you tried to connect the extra speakers? That is, did you actually hear the FM playing?

A T antenna is 300 ohms, not 75 ohms -- but that has nothing to do with your problem.

In general, if any FM tuner is working, and you live in an area of reasonable signal strength, a foot or two of wire will pick up _something_. If you can't get _anything_ -- something is wrong with the tuner.

If the display shows the RDS correctly for the station tuned in, then the antenna and at least part of the tuner are working. That means something "down the line" is kaput.

Yes, that's what confused me into thinking that something else was broken. For a short while, the receiver was playing with the antenna. But after a few minutes I tried to hook up the second pair of speakers to the same terminals and the moment I did that it suddenly stopped playing, as if some kind of fuse broke or some kind of protective circuitery jumped in. But for what I can read here (and I did not yet say this enough, but I do appreciate all the help you have given, folks!) , both fm and speaker connection would have nothing to do with each other... Well, I think I must accept the fact that indeed something "down the line" is broken and perhaps it's time to get it replaced with another tuner.