Intermittant JBL Stereo CD Fix

vancouverBC

Registered User
Intermittant JBL Stereo CD

I have been trying to fix my random stereo failure for quite a while. Symtoms: Hot days, No sound. Works fine in the morning while everything is cool then it stops for no reason. Whenever it stops, the lights on the CD go out but the lights on the radio stay on. Everything works fine as long as the engine is not running and the key is on Acc.
Things I tried: Replace the radio, replace the harness, replace the alternator, replace the AMP, resoldered the wiring harness, jumpered the radio plug, replaced a relay inside the CD player, and maybe few other things that I can't think of right now.

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If those are potentiometers (they appear to be) some of them will build up corrosion on the contacts and just moving them off that point in their rotation cleans them enough to bring them back in line. Might be a better idea to buy some contact cleaner at Radio Shack and spray them with it. Mark the start position and turn it stop to stop 10 or 12 times returning it to it's original position.

However if a 1/4 turn works, it works.
 
I have no idea of what those parts are called nor what they are for and since there is nothing written on these systems other than that they are not serviced any more and to buy a new system. I just took a chance because I didn't have much to lose. VR01 & VR02 is stamped on the board near them, if that means anything. I would replace the whole modual if I could get one. If the problem returns, I will take your advice and use contact cleaner on them. Do you know what that modual is or what it does? 1-464-910-11, ZSSR701D, Ser.No. 010351 is printed on the case.
Thanks
 
Cool.
I think I will give that a try with mine.
I actually had that thing apart but only tapped on those
potentiometers, not actually turn them.
 
Variable resisitors are used for creating adjustable voltage and current levels in a circuit. Anywhere you need to be able to "tune" an amplifier feedback or adjust the input of a circuit to get a particular voltage or current output a potentiometer is a possible component. I'm guessing (GUESSING) these two are in a voltage regulation circuit of some sort from the looks of the surrounding components. They're probably used to adjust or regulate the 12v supply to something else for the circuitry in rest of the unit.

I've got two dead CD players on my workbench that I was going to try and fix and this will help if I ever find my round tuit ;)
 
That was helpful thanks. All I know is the radio has to send a signal to the CD and the CD has to send the same signal back to the radio in a constant loop. When that loop is broken, the CD goes off, and no sound from the speakers. When I unplugged the CD from the radio, I could only hear faintly through the speakers, but good enough to know that it did not cut out after days of trying. There is supposed to be a vibration adjustment and an overheat shut-off inside the CD player. I didn't know what they looked like so I was just looking for burnt parts and didn't find any. Good luck and get to work on those other 2. Thanks
 
Rats

I pulled mine and twisted them left and right they felt fine, no corrosion felt and Drats no worky, I think 14 year old JBL systems Suck
 
I ended up breaking a ribbon cable in my CD player while working on it. So I picked up another factory CD player from a guy that had gone for an aftermarket system. Everything worked perfect from the moment I plugged it in. So the problem was the CD player, as I thought. Good luck
 
I got the same problem only my cd cuts out once it gets cold outside. I took the thing apart and tweeked on the pots a little but no help to the problem. Does anyone know what the cd overheat switch looks like or the vibration tunner. Love the car just would be nice to have some tunes once it gets cold.
 
Risky Business

Adjusting the two potentiometers talked about in the original post can be a little risky and I'll explain.

The board that the "pots" are located on is the switching power supply module for the CD Player. It takes in +12 Volts and generates + 5 - 5 +28 +32 Volts DC. The two adjustments control the +5V and -5V. These voltages are used by everything on the main circuit board and proper adjustment is essential.

The problems all start due to the fact that Sony (the OEM for Ford) used crappy capacitors in all of these earlier units. They prematurely leak with time and heat and when that happens, all sorts of problems can develop. When the ones in the power supply module start to go bad, the voltages start drifting and pretty soon, the CD Player will only power-up when it is warm. Over time they continue to degrade to the point where they won't power-up at all. This is because the voltages are nowhere near where they should be.

It's true that you can adjust them to get the voltages back close to where they should be but the risky part is that the bad capacitors are now very prone to SHORTING-OUT and if that happens, you'll have more bad in the unit than just capacitors.

Also if you adjust the voltage to a good level when cold just to get the CD Player to work, by the time it heats up, the voltage will be too high and the risk of blowing a lot of other components goes way up.

My advice to all of you would be to take care of the real problem....have all of the bad capacitors replaced when you first start experiencing problems. Once they short out, the entire main board could end up being toast and therefore unrepairable.

These stock radios and CD players are quite good when they are operating right. The radios have the same problem with bad capacitors. They cause all sorts of problems when they start failing but replacing them will make the unit sound and act like new again and last far longer than it did originally.

I repair both the CD Players and Radios in these cars as a hobby and can say without any doubt, over 95% of the time, the cause of the problems is just what I described.

Wait to long to take care of the real problem and you can kiss it goodbye.

Just my two and a half cents worth.

TwoTimeSC
 
Thanks for your help giving us more info on what is really going on, I couldn't find any other source of info on the subject before I started experimenting with it, including the local Ford radio repair shop. They said that there was no info or service for them and to just replace them. Now that you have added your advice, I will delete the post on adjusting the pots so oneone damages their CD and follow your advice for the next time mine goes south.
I have also found that loose engine grounds to frame and pass fender grounding helps with constant radio reception. Thanks again and Good luck
 
Could you list the problem caps (c-12 c-25 ect.) I’m not bad with a soldering iron and I have two of these units that are intermittent.
 
Problem Caps

I wish it was that easy Motohead but Sony had 2 or 3 suppliers for their capacitors and at any given time they may have used the BAD ones in any location. I've seen some CD Players that only had 10 sub-standard ones installed all the way up to about 24.

The radios are even worse. They typically have anywhere from 12 to 60 of the faulty ones. Again, Sony may have used them in any of the 130 or so locations for them. (Main board, pre-amp board, amp board, tuner board, and cassette board.

They all must be tested and the faulty ones replaced.

This usually takes me about 2 hours with the CD players and 6 hours with the radios.

Sorry I wasn't much help.

TwoTimeSC
 
Thanks for the info. Now knowing that there isn't a so called easy fix I'll send the cd player out to someone who knows what they are doing. I had problems with the radio years ago and it cost me about 90 bucks to get it fixed. I agree that the sound system is pretty good when it works and dumping a little cash to get the orginal equipment fixed is well worth it.
 
Hey Fordified,

I would be glad to quote you a price to take care of you on your CD Player or Radio. Just fire me an email if your interested. I guarantee my work, stand behind it, and have repaired / reconditioned about 36 units now.

polyscroll@hotmail.com

Thanks,

TwoTimeSC
 
Whatever !

that is the biggest line of Crap I have ever heard ! capacitors dont change capacitance from hot to cold, niether do resistors, transistors, diodes, or zener diodes. so adjusting them when cold and having them not work in the heat is BS. sony's oem board uses the same capacitors that you and I can buy from radio shack or any other source so cheap capacitors? go snow someone else lets try to keep these boards legit. if I am reading your post right you basically changed every component in your system then when it still didnt work you moved some potentiometers and tapped on something that you thought might be the heat limit switch. PFM struck and now its working. well it didnt fix mine or the other 3 guys asking what exactly you did. maybe we should take an advanced electronics course so that we will know that unless your buying military your capacitors are the same as everyone else's......... wait a minute ! one of us has been through 12 years of advanced electronics. radio still doesnt work !!!

for $ 89 and any internet car stereo site...... problem fixed !!!
 
Just bought my SC and after 13 years I was surprised to see all my JBL stuff was still in it. Usually it's gutted. Anyway mine does'nt work. The radio comes on but there is no sound to the speakers other than a cackle every now and then. The tape deck rewinds and ejects and all that but no sound. Do you think I just need a new Tape deck. Is this usually the problem and not the amp or sub?
 
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