Parts needed! Help! I broke a black thingy!

caver01 · #1 11-01-2002, 05:10 PM

Ok, this is a little sad and embarrassing, but last night, while fitting my second battery into the chassis, I snapped a little black round component clear off the circuit board.

This is the smaller cylindar next to the larger one, under the PCB on the passenger side. I think it is says 101k CEC on it, but it's tiny. Does anyone have any idea what this is? I assume it is some micro capacitor or something, and I should be able to find one at digikey or something, but I am at a loss. An order-able part number would really save my zz, and I'd rather spend 5 bucks and do some fun soldering than have to go buy a new car!

Any help on this? Anyone?

Nightwing · #2 11-01-2002, 08:22 PM

The bigger is a capactor but I think the other is another coil but not sure. Just got to that part on the diagram last Sunday. Not sure if its on a daughter board along with the large electrolitic cap. It looked strange and my eye were screaming out of my head from tracing circuity so stop just before that section.

I think this part of the board is the inverter for powering the receivers & decode chip. Just a guess for right now.

It may be a custom part. Is it intact? IE does it have the two leads sticking out of the bottom? Some time this weekend but not sure when will be finishing the resistor forest on the "bottom" side and getting into the PS side. At this small scale it a real eye strain to trace and figure thing out.

Nightwing · #3 11-01-2002, 09:42 PM

If its the same part you may be abble to resolder the little nightmare.

Basically its a coil and could be a iron core but unknown as of right now.

Did a blast on that section and its a power inverted. Takes 1.2v in and produces approx 3.2v out.

NOTE: This is a plimnary diagram and will be subject to change. So the normal use at own risk. The part that broke is L4 on this diagram.

It feed voltage and part of the osc circuit ithink for the inverter.

Ok The part that broke off is a coil. If you have an ohm meter see if you get a short or very low ohms reading. Proabbly under 250ohm's. If not see below under RATS.

If you get a reading then clear out the holes with a solder iron and either a pick or a woddend toothpick. Insert and resolder.

Set a meter to read abour 3.5 volts. Charge the car and see if on the plus terminal or where it feeds C17 and R4 should have around 3 volts DC. Ground is that outer tracing verified where the Black wire is solder to. If you got voltage seal it up and HAVE FUN!

RATS:
If you get no reading might as well go for broke. With a sharp knife very careffuly cut with small light strokes the shrink tubing from the coil. This should expose the inner part. You should see a bobbin with a lot of wire wraped around it. One of the ends is broken. You may need to pull a bit but not more than a wrap or two. The wire is proabbly std magnetic so you may need to scrape or burn off the enamel coating but not too much! When you get a reading across the terminals make sure it solid and wrap with about 3/4 inch of tape. Slip Not Gray is the best but Ugh electrical or even celaphane will do. If yo have acces to shrink tubing is the best way to do it.

POSSIBLITY:
It could be around 10000uh {?} so if you cant get it worrking may see if you can scroungs something around that value. Got a inducantance meter some where around here. May pull the part and if in range measure it.

Good luck.

caver01 · #4 11-01-2002, 10:07 PM

Okay, this is a little beyond me. Well, I could certainly stick a new one of these into the board and resolder. That I can handle. But this thing is broke. I doubt I can make it work at all. The pins are still securely soldered to the board, but their round tips broke right off the black cylindar. The end of the barrel has two round holes where the pins used to go. I have not sliced open the shrink yet to reveal any coil. You know a hell of a lot more than me about this, so I am guessing you are right, but if I do reveal a coil, I don't think I am going to be able to make it work again with the pins completely pulled out like this. I doubt I can even find an end of the magnet wire if it is in there someplace!

As for measurements, I have nothing to measure it with. I don't own a meter. Besides, without the pins attached, there is no contact points! Well, serves me right I guess for messing around, but that's the fun of it all!

If you DO figure it out, or anyone else reading, and there is a simple replacement part, I would be willing to pick it up and test your theories. Isn't there some diagram for this thing that someone found at the US patent office? I thought I read that someplace.

Thanks for the info, but it's just a bit over my head. Awesome work on the diagram!

Nightwing · #5 11-01-2002, 10:28 PM

The part is all mechanical so it could be repaired. Even with the pins out of the bottom.

The only diagram avaiable and required by the FCC is the diagram of the transmitter.

Which you can get by going to www.FCC.org and typing in the FCC ID number. The diagram is simular to the bit/MS diagram.

Also I did some digging at RS and since the cost of the car is so low they WONT have a service manual on it.

If I can either find the coil meter or do a test will try to get a value for you. But cant promess when.

Sorry.

Nightwing · #6 11-01-2002, 10:51 PM

Did a quick search. Odds are its a 100uh inductor. The problem on this type of part is they have a minum number you must buy usualy its around 100 or 1000.

Coils are the simplest and easy to fix or make electronic
componet.

So if you want to risk it. Open the little fella and see where it broken. You may be abble to solder two wires to the end of the wire inside and seal it back up. Ends from a reisistor may do the job.

Like the top crude diagram.

If there is no ferrite or iron inside wonder if you took a 10 megohm resistor ( axial lead 1/4 watt )and took the winding off and wrap it around the body of the resistor. Solder one end of the wire to one leand and the other to the other would it work? Like the bottom diagram.

Good luck!

caver01 · #7 11-02-2002, 01:04 AM

Okay! This is going to be fun. I have some time tomorrow. I will try taking it apart. What do I have to lose at this point, right? I will let you know, and take pictures at the same time. THANKS!

#8 11-02-2002, 03:35 AM

Do a quick solder job and take it back to radio shack!!!

Nightwing · #9 11-02-2002, 06:18 AM

Good luck tomorrow! Or is it today?

caver01 · #10 11-03-2002, 01:23 PM

Thanks for the "returned merchandise" idea, but I don't really believe in doing things that way. Besides, I'd rather have the parts.

So, I did what you suggested, Nightwing, and I gotta tell ya, after squinting for 3 hours at that coil, I got a headache, but it it turned out great! Thanks so much for the insight. I opened up the wrapper and inside was a coil, exactly as you said. That was some thin wire! Anyway, I had a bit of trouble tinning the tiny leads, and actually had to do the entire process twice, as the first time didn't work. I ended up uncoiling about 6 inches of the wire before I found the buried lead again, and this time, I was VERY careful about it. I wrapped the wire back up as best I could, scuffed the easy end with some 320 grit sandpaper to take off the enamel, and soldered and glued the pins back on. Finally, I put new heatshrink over it (for the second time!) and soldered it back to the board. Here are some images of the coil before, then after my repair (the first time) and the final component installed again. Wow, what a rollercoaster ride. For the time spent, I could have easliy bought a new one, but this experience was pretty valuable to me. Thanks!

caver01 · #11 11-03-2002, 01:29 PM

Oh, I should mention that in the end, both ends of the coild wire were at the bottom. One end of the wire was obviously easy, as it was free to unwind, but the other end was buried at the bottom of the coil, just a tiny end sticking out from under the coiled wire. That's why I had to unwind so much of it to get at the other end. This wire is as thin as hair!

Nightwing · #12 11-03-2002, 03:29 PM

OUTSTANDING! CONGRAT'S!!!!

I though it was thin but that thin? Wow. Coils are the simplest thing in a circuit. Basically it just wire wraped around something.

Did you just use your eye without a magnifier? Should have mention something about using a magnifier. Sorry.

Been chasing the foil layout on the pc board figuring out the circuit for everyones reference on the receiver. I know what you mean about the eye going after a while. Esp my old eyes!

What you did is exactly right!

Scraping the enamel off of the wire is always hard. The mfg will use what is known as a solder pot. Simply a small container that keeps about pound of solder hot and molten. Simply dip and it tins and burns off the coating.

The thing is "you did it yourself!" Congradulations!

caver01 · #13 11-03-2002, 10:43 PM

Thanks. I did it by eye. Didn't occur to me to use a magnifier until after! Oh well. I have pretty good eyes up close, so it was not too bad, but I did get a headache. Now, if I couldjust figure out why my dual battery mod isn't working. . . it was working fine before I decided to rearrange things under the board, and look where it got me! Thanks for all your help.

Nightwing · #14 11-03-2002, 11:09 PM

Wow that was outstanding!

Good luck on the problem. You will make it!