My girlfriends car caught on a fire Saturday, and the fire dept. put it out. Of course, they have to thoroughly soak the car to make sure it isn't going to catch fire again on the back of the tow truck.

My question is, her radio was in the car, with the faceplate off. I pulled it out and besides being soaked and sooty, there is no damage. I pulled it all apart and used a hair dryer to dry it. I then left it apart overnight and put it all back together today.

The radio works fine, all the buttons seem to work, all 4 speaker outputs work, but when I go to put a cd in, it will suck it in, say PLAY --:-- for about 10 sec, start a really quiet ticking for a few secs, then spits the cd back out.

I took it apart again and tested the motor that spins the cd, the motor that pulls the cd in, and the motor that moves the lazer back and forth; all function fine.


Any idea on why it doesn't work? I'd just get her another radio, but I bought this for her on out 1 month anniversay 3 years ago, so it's sentimental to her. Probably more so as it was in her pride and joy when it went up!

 

theres probly soot on the laser...... you can try running a cleaning kit on it a few times.... or take it apart (carefully) and clean it out...

 

Ahh, that I did not try! I will let you know if it works. I gotta go buy a cd cleaner now lol

Till then, anyone else have ideas?

 

sounds like you are a do-it-yourselfer!

to avoid a costly bench repair from a professional you should continue to gather info on the radio. try the library for some electronics books: fixing consumer electronics without a schematic is one of them, I haven't read it, but it sounds right to me. You know enough to test all those motors...and you thoroughly dried it before energizing it again, so your on the level. get anything you can from the manufacturer, schematics, tech briefings whatever they will release to the public.

I once searched for electronics technician's forums and found several, some have threads that discuss consumer electronics circuits like we discuss thirdgens here. Geek heaven!...j/k, some of them have brand/model specific info and parts listings ect..better than going blindly, as is a very difficult repair for any tech. Cleaning is definitly a good idea, check out an optics supplier or electronics store to get some GGOOD cleaning product for the laser lense and the rest of the circuit. you should be able to remove the entire CD sub-unit with the removal of four very small screws, spray down the rest of that with some safe electronics cleaner. Bring it in and ask the supplier what's best or thoroughly read the label of any product you use.

Since it must have been powered, at least on the yellow b+ wire, it is a small mirical that it still works at all!

 

More then a small mirical.

What is the make and model number? Hate to say it but the chances of it working right for long are not vary good. Corrosion is like cancer to electronics, once something gets wet, it a gamble at best. It may work now, but for how long.
But, it IS working now so you’re on your way.
How did to test the motors? Did you remove the leads for the PCB?
From what you described, it sounds like the optical pickup is not focusing or seeing that it is focusing. The optical pickup may be bad. Like the others said, clean the lens. But keep in mind that this only cleans one part of the pickup, there are four other surfaces IN the pickup that you can't clean. If the unit was "soaked" these surfaces are probable dirty as well. The next to most common cause for the symptom your describing is a servo problem. Take a good look at the servo IC. It should be a SMT DIP package with what looks like one really fat lead in the center of each side. Look for ANY sign of liquid damage there. It may take a week or two for corrosion to become visible.
If you’re still having problems get back to use with the make and model of the unit. I can see if I can get the service info.

 

This is the radio: JVC KDS550 AM/FM/CD deck

I desoldered the + lead of each motor before testing it, as to not fry other things lol

There are 2 surface mount dips on the board... but the board looks pretty clean; besides the soot on the trace side near the RCA jacks.

Can I clean it with, say, alchohol and a toothbrush?

 

cool, all electronics people in here!

I'm no expert with consumer products, but I'd try using some ESD safe spray cleaner. For $5-15 for a can, it's worth playing it safe and you don't need much.

Alcohol and tooth brush will work fine though too, denatured alcohol and an acid brush trimmed into a 'scrub' capable brush. That's what I use to clean flux away after I solder a PC board together.

 

Yes, I have a can of PCB alcohol (90% I think) that seems to work better than a can of Flux-Off lol

 

OK, KD-S550. The servo IC is IC541 (LA5557) And the focus outputs are pin 8 and 9 with the focus input- at pin 16. Tracking output at pins 10 and 11 with the input at pit 12 and 13. Probably more info then you need.
If it comes to it the optical pickup part number is OPTIMA-720L1 but the OPTIMA-720A1 is a good cross and cheaper some times. If you replaced the optical pickup note that there is a tension spring on the slider side. One side will attach to the worm gear, which’s the driven side. The other side just slides. The new pickup will not have this spring and there is NO JVC part number for it OR the little screw for it so don’t lose them. If you do let me know, there is an Aiwa Part number for them (Aiwa uses JVC pickups). It will still work without it but it WILL skip at every bump in the road.
Also if you get it working take a good look at the solder connection at the RCA outputs, the antenna connection on the main PCB, and at the power supply IC (IC901, BA4905). Bad solder connections at these points are VARY common with this model. Also make shore there is no corrosion starting at the microprocessor (IC801).
You don’t need to worry about ESD safe sprays, just don’t get ANY near the optical pickup. Some solvents may discolor the lens. And I would use the strongest solvent you can get for cleaning the PCB. Clean the lens with denatured alcohol and a Q-tip and be vary careful, you don’t what to bend the little arms that hold the lens.
If you go though all of this and everything is working but it is still not reading the CD, replacing the pickup is the next step. I would let it set for a week or two and see if it still works before ordering the pickup. Liquid damage will act vary strange, it may work now and not in a week.
Once water gets into the unit you may end up having some feed thoughts go open or corrosion stating under some of the ICs or other parts. Corrosion will start where you can’t see it, under IC, larger caps, and it loves the under side of the harness connector. Good luck.

 

Well, I tried a CD cleaner... the kind with brushes... and I could not hear it brushing, so now I know what the problem is; it isn't spinning. I did test the motor though, and it spun fine... so I guess it's the circuitry.

I had this radio apart about 2 years ago to resolder the RCA jacks... the middle pin had come off the board and was making horrible crackling noises thru the sub!

 

Thanks for all the info, you sure know you're stuff! Where might I order the pickup if I need one? Any idea on cost? I'm going to check the MCM and Jameco catalogs now... but these thing must be obscure.

 

Thank you.

MCM has the 720L1 and the 720A1 for $35.65
Just had anther look. It looks like they both sub to there part number 32-17720.

http://mcm.newark.com/NewarkWebComme...ext=optima-720

Don't forget about the tension spring, do NOT lose it or the little screw.

If you've never replaced an optical pickup you need to know that when you get it there will be a pad that's shorted with a blob of solder. This is to protect it from ESD in shipping. The laser diode in the optical pickup is ESD sensitive. You should ground your self before handling it or use a ground strap. This is especially important in the winter with all the dry air. You MUST remove this once the optical pickup is in the unit, make it the last thing you do. But don’t forget about it. If you power the unit up with it there you run the risk of damaging the regulator transistor for the laser diode. More things to fix.

Just remember it's a gamble with liquid damage. It may only work for a shot time. I normally recommend getting a new unit if it has gotten wet.

I would sill recommend you let it sit for a week or two before you order the pickup and see if any corrosion sets in. Once you see corrosion it’s usually too late.

Best of luck to you...

 

Ok, thank-you for the link. I will wait a while and see what happens before I buy new parts.

Can you buy head units without faceplates? The faceplate wasn't in the car when this happened. Or would they think you just stole it? lol

I guess I'll have to watch ebay for one with a damaged faceplate!

 

Is that actually a KD-GS550JK? I happen to have a working faceplate, harness, and instruction book from one I bought off of eBay.. I threw the rest out because the CD loading mechanism was FUBARed and the outputs kept cutting out the sound...
I think I still have those parts anyways.. if that headunit is the GS550JK, I'll look for the stuff.

 

Well, thing is, I have the faceplate... I am in need of the unit itself! (If I can't fix it)

 

You happen to be about two months too late for that... if only it happened two months ago, I'd PAY YOU to get rid of it....

Okay, I know it's been two days since anyone posted in this topic, but I am going to say that there is a SLIGHT chance I MAY still have the headunit, although I am pretty sure I put it into an outgoing trash bag. It is going to have to wait a few days until it warms up to above 0* here (yes, it is THAT cold) so I can get the big trash can into the garage for defrosting and go through the garbage bags in there. But the chance of me finding that headunit is most likely in the 0 to 8.24% range, with 100% being that I will find it...

And if you need either the wiring or the manual, say the word. I at least know where that is... I'll even send the faceplate to you for free. I sure as heck don't need it...

 

Bought a new laser pickup unit thing from MCM... and the radio is alive! Kinda sensitive to skipping now, so I guess I have some adjustments to make!

 

NO NO NO, don’t adjust any thing. Way to E-Z to get that thing outa-whack. If you don’t have a service manual, a good oscilloscope, and KNOW what you’re doing, don’t turn anything in that unit. That little variable resistor on the back of the pickup IS factory set and you NEED an o-scope to monitor the RF pattern to get it right. Otherwise you get twisting $hit. And if you already tried, put it back as close to where it was as you can, it WILL NOT be right but may be close. You should check over you work, make shore that you got the tension spring put onto the slider side of the new pickup, if you forget that it will skip BAD and the new pickup didn’t come with one so make shore you swapped that over. If you got that check the shocks, the rear shock on the back of the deck goes bad on the JVC all the time. If it’s leaking at all it’s bad, if not that should be good. Check the springs. Try holding the deck right side up with a CD loaded. If any part of the floating mechanism it touching the fame that WILL make it skip. The floating portion of the mechanism must be floating or any tapping will make the thing skip.

 

Ok, I haven't touched the pot on the pickup yet. I do have an oscilloscope though, possibly you could talk me thru it?

I checked everything, and it looks just like the digital pic I took before I took it apart (if you have a camera, best idea ever!!)

 

OK, first off, JCV are not the best at skip rejection to start with. Are you shore that it is more likely to skip them before? If so then did you take the little tension spring off of the old pickup and put it on the new one? It is on the slider side. There should have been a white plastic part with a metal tab on the side with the worm gear, on the OTHER side there should have been what looks like a metal tab, was it on the old pickup? If so it must be taken off and put on the new pickup. Check that first. If you didn’t move the pot on the pick up you should be good there, I’ve never seen an optima pickup come in not properly aligned. Sony pickup yes, optima pickup no. Also, if the spindle motor got wet that could be bad to. Try spinning the spindle motor slowly be hand, if there are any rough spots then it bad. The spindle motor is the one the turns the disc. Let me know what you find.

 

Ok, no I did not adjust the pot... it's right where it was when I got it.

The spindle motor seems ok, and it plays cd's ok.

I did put that spring back on, but I will check to see if maybe it fell off. This thing skips if I touch the radio at all. It used to handle bumps ok!

 

Do this, double check for any signs of corrosion, especially under the legs of the SMT ICs. Double check the spindle motor, when spinning there should be NO ruff spots, and there should be no side to side movement of the turntable. Put the unit all the way back together, making shore there is nothing on the mane PCB that will touch the “floating” potion of the mechanism. A CD player’s ability to resist skipping comes almost entirely form the shocks and springs dampening ANY shock to the pickup/disc. When the disk is playing listen for any kind of rubbing sound, like the disk is rubbing against something in the mech.

“Just remember it's a gamble with liquid damage. It may only work for a shot time. I normally recommend getting a new unit if it has gotten wet.”

Unfortunately you may end up chasing bugs for a long time.

 

lol well, I'll pull it apart again and check those things. Thanks for the help!

 

You happen to have any bad CD's? I used one of those spacer discs (one that doesn't have anything on it and is clear), glued a piece of 80 grit sandpaper to it, and rotated the disc until the discs no longer rubbed the mechanism.

However, my unit had some sound problems (intermittent sound output) and the loading mechanism only worked properly when you held pressure against the CD while it was loading and unloading, otherwise it would jam and you would have to go back in and unjam the thing.

The CD rubbed like mad against the carrier (big black holding mechanism) because of the white tabs on the top. Make sure the tabs aren't pressing on the CD or are actually sitting on top of the cd instead of a small distance away from the sides of the disc, because that jams the mechanism and does not allow the disc to turn. If all of the springs are installed in the right places (the longer ones go in the back IIRC... the six ones that are the same length go at the front) and the anti-shock cushions are good, then the CD won't skip as bad unless the laser is out of focus or needs an adjustment of sorts.

 

Hay, aaron7, you ever have any more luck with this.

 

Yes, I did. It's working fine now!

 

what did you end up doing to fix it?

 

I took it apart again, and the spring must have not been on all the way, as it was off!

So, total I had to replace the laser unit (MCM Electronics) as the innards got wet and dryed... and it was dirty water.

The skipping was due to the little spring on the laser unit being off. This little part does NOT come with the new laser unit, so keep it!

 

I think it would have been much easier to just replace it, unless it was a really expensive deck like $400 dollors or more, it should have been cover by insurance anywayz.

 

I was hoping that the insurance would have covered it... but she had only the base insurance (I hit you and I hit your property) and glass.

The radio was sentimental to her as it was the first present I gave her, and it was in her first car and her favorite car that burned!

Plus, it was only about $40 total to fix it. Just lots of work!

 

I think I remember a warning or two about that little bugger. Glad to hear it's working now.

It's THAT important.

 

Oh I know! I read all those posts and saw that; I was just so sure that it was on there!

 

Wow, not as old as some I have seen. but this thread is way old...
Anyways, to the point:
I managed to dig out the old JVC unit and have decided to try to get it working again. The main PCB wasn't bad, just a couple of water spots on the bottom of the board and some dirt on top and that was it, same with most of the connectors. My biggest beef is with the CD tray. Mine, no matter what I do, won't hold the CD upon insert/eject and half the time cannot load properly when I hold a finger on a disc to get it in there. Another problem is that the tray pinches the CD a good 70-80% of the time so the disc won't turn, and I am looking for a way to fix this. Since I have the same exact unit as aaron7, I was wondering if he might be able to help with this. Also, some of the time, the stereo would work but the sound would cut out for some reason and not come back unless I unplugged the unit for a minute and hooked it back up.

I have all the hardware except for the plate that holds the faceplate on and the connector cord, which I am positive is buried here somewhere, and want to put this in a second car... 22W x 4 channels ain't bad, is it?

 

Hey, that's 45w peak! lol


I'm not really sure how to help with your problem, as the only mechanical problem mine has is the cd doesn't eject any farther than 1". Then you have to grab it before it sucks it back in!


If you tore it down, maybe it just needs a little lubrication?

 

OK, first off in an earlier post you said your HU was a KD-GS550, NOT “the same exact unit as aaron7”. He has a KD-S550.

Second, you already more then likely destroyed the mechanism. “You happen to have any bad CD's? I used one of those spacer discs… glued a piece of 80 grit sandpaper to it, and rotated the disc until the discs no longer rubbed the mechanism.” This was a turntable height alignment problem, but it’s much worse then that now. Now it’s a turntable height alignment and what ever the h3ll you sanded needs to be replaced.

Third, “However, my unit had some sound problems (intermittent sound output) and the loading mechanism only worked properly when you held pressure against the CD while it was loadin....” The intermittent sound is bad solder connections, VARY common on JVCs. The loading problem was a just bad rollers, that’s it. Cleaning them with a good “rubber” cleaner will get them to work of a month or two but they need to be replaced. But it is probably to late for that now.

And now, “Another problem is that the tray pinches the CD a good 70-80% of the time so the disc won't turn...” This is usually because of the rollers, but with the little sanding thing, g0d only knows what is going on now. There is the possibility that there is something going unrelated to the sanding disk thing, but not something that it will be E-Z to walk you though.

My best advice on this one, TRASH IT. Way to much going on to even bother with it. Intermittent audio, loading problems, turntable height, sanded parts, bad rollers, missing the front plate, and……
T
he lesson, DON’T just go sanding on parts, fined out WHY they’re rubbing and fix THAT problem.

 

That's loading rollers. Try try cleaning, then replace.

 

Haven't destroyed anything. I bought the frigger this way...
Don't have rollers... has two white levers, per side, that hold the disc in the tray while the tray gets sucked into the unit by another white gear arm on the actual CD reading unit. If I could get you guys a pic I would, but the dig cam is broke...

I already told you guys why the damn thing rubs like heck on the disc and all you say is to trash the unit... Why do I even bother in this forum?