Car electronics

***glennzo*** · #1 2nd July 2008, 10:03 AM

Any automotive electronics wizards here? My car radio doesn't work. That is it doesn't work on FM. AM is fine and the CD player is fine. If I switch to FM it may work and if it does it may work for 30 seconds or it may work for an hour but it always quits working at some point. It acts as if there is no antenna attached and it can't get a signal. Sort of like I'm miles from the nearest station. I've checked the connections on the back of the radio (took it out of the dash) and they were both tight. The antenna plug looks fine. I've tried a new antenna mast, which is on the roof. Yesterday it worked for over 4 hours with no problem, then it quit. Just stopped working. It's not a power issue as the radio is still on even though I'm hearing nothing.

This car is a 2002 Ford Focus. AM/FM/CD

Evil_Bert · #2 2nd July 2008, 10:09 AM

Sounds like you've already isolated the defect to inside the radio/CD unit. Recommendation: repair or replace the radio/CD unit.

***glennzo*** · #3 2nd July 2008, 10:19 AM

Hi Evil Bert. Thanks for your reply. I'm pretty much convinced that I need to replace the unit but that's what I'm trying to avoid. If I do replace it it will be with a junk yard unit. Before I go that route though I was thinking of investing < $10 for a cheap antenna just to see if it helps. If I turn the radio on right now it will probably work on FM and work well but it will likely start to fade in a few minutes, as I said, as if I'm out of range of the station. Then it will just stop working. I can switch to AM immediately and it will work just fine. If I need to start calling junk yards so be it but what do you think about a bad antenna or a bad antenna connection?

I do agree that the unit is probably junk.

tsorvoja · #4 2nd July 2008, 10:20 AM

First check cabling. If fault is not there then it might be bad soldering at some circuit in FM radio part of the unit. Vibration and/or heat might affect in functionality in this case. Unfortunately there is no quick fix for this. If you like tinkering search the bad soldering by pressing partscarefully at circuit board. When it's found, then solder it properly to the PCB. Start from antenna connection to FM demodulator and so forth.

tsorvoja · #5 2nd July 2008, 10:22 AM

I missed your latter post. The sound fading issue sound like bad soldering heating up in the unit and making a bad connection. When the unit cools off then connection works again.

***glennzo*** · #6 2nd July 2008, 10:24 AM

Quote:

Originally Posted by tsorvoja

I missed your latter post. The sound fading issue sound like bad soldering heating up in the unit and making a bad connection. When the unit cools off then connection works again.

I agree. I might add that at times it seems that bumps in the road affect the operation of the radio, again, FM only. Thanks for your interest.

robert-e · #7 2nd July 2008, 07:26 PM

If you can get it working out of the car and on the bench, open it up, fire it up, and use a can of freeze spray to cool suspect components one at a time, until you find the culprit.

Bob

techmatt · #8 2nd July 2008, 07:30 PM

good idea, I would have never of thought of that one.

I would focus on the FM receiver chip (I think it is only one chip now a days)

***glennzo*** · #9 2nd July 2008, 09:41 PM

Hmmmm.... Too much work to do all that take it out, take it apart stuff.

I think I'll start calling the local yards. I was hoping that there would be one of those fixes like pushing the little red button on the back of the radio, wait 30 seconds and try it, or something on that order.