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2000 Factory Mopar Spare Tire Sub Help Needed

The fact that you guys have picked up on all of this just by looking at the board makes me wish I wasn't such a spaz when I was a kid and had paid more attention in the electronics class I took.
 
You can always pick it up if you've got the "engineering mind", or are inquisitive enough... I've been an electronics hobbyist since I was 7 and now work in the industry, so it comes pretty naturally. I can't even tell you how many times I've fixed friend's electronics by resoldering a few joints, replacing a few blown transistors/capacitors, etc. I still haven't bought an LCD monitor for more than $25 because I keep picking them up for free/very cheap on trash day, ebay, craigslist etc and replacing parts till they work. Really hoping the OP has a similar issue, because it's usually not too hard to fix stuff like this.
 
I hear you on fixing broken stuff. I have friends and relatives just dumping broken stuff on me because they know I like to "tinker with dead stuff". Usually it's a simple and cheap repair like bad solder joints or dried up caps, or maybe a more difficult challenge that I'll enjoy solving. I usually give the repaired stuff away, resell on eBay, or just donate to the local Goodwill. I confess that I often search ebay for broken, non-working, dead, no-power, etc. Got some great deals that way.

I truly enjoy the fact that I have some auto, home, and electronics skills. It fits right in with my cheap-sob personality. It saves me tons of money and I enjoy doing it (well except for doing drywall...)
 
What's wrong with drywall? I like it more than insulation or roofing... :D

Any part numbers yet? I am curious as to what exactly those parts are doing...
 
kastein said:
What's wrong with drywall? I like it more than insulation or roofing... :D

Any part numbers yet? I am curious as to what exactly those parts are doing...
Click to expand...

I don't mind hanging the drywall. I just suck at mudding and texturing. I'd rather pay someone who can get it done quick and make it look nice, instead of me spending far more time and having it look so-so when I'm done. Lack of practice on my part I guess.
 
Greenz said:
Bottom picture:

2 large grey squares with hole

2 smaller grey squares with hole

2 black rectangle with hole

They were held down with a clamp to the heat sink.

Just write down any numbers or leters you can see on them.
Click to expand...

Ok so I did a drawing because I felt it would be easier to show the letter and number placement. I looked over all the connections and they look good. This unit was bought new in the pkg last year so I hope it can be fixed since they are no longer produced. I hope this information will help.

Thanks in advance. If you nned more pictures let me know.

CircutBoardLayoutSUB.jpg


Picture012.jpg
 
Aha! Thanks for the clear drawing.

The B688 is a PNP power transistor (full part number 2SB688, there are so many subseries of the 2SxNNNN transistors that no one bothers printing the 2S anymore) of the same characteristics as the 2SD718 NPN power transistor. This probably means it's in a push-pull amplifier design like we guessed.

The IRFZ34 (there are two of those) is a power MOSFET, since there are two I am betting these are part of a DC-DC converter power supply for the amplifier. This is reinforced by the fact that there is a large multi-winding inductor/toroidal transformer on the same PCB and near them. The two packages with the arrows on them are actually dual Schottky rectifier diodes, the arrows should be filled in and probably actually point at each other (or away) instead of both in the same direction.
 
So is there a way to test them? As far as the ones with the arrows I have not touched them. They were installed by the factory.

Thanks
 
Hmm... what you can do is trace the wiring from the board with the diodes and MOSFETs on it (the board with the smaller ones) and figure out which wires are the positive and negative power lines to the amplifier. Check the voltage on those, though with no data on nominal voltages it'll be shooting in the dark. Also, just curious... that metal tab on one of the boards, you screw that down to the frame of the amp right? That's the ground reference for that board, so with it floating, it could cause the problem all by itself.

Since it's a discrete component amplifier you could simply replace every semiconductor and questionable-appearing part on each board, but that's probably overkill.
 
kastein said:
Hmm... what you can do is trace the wiring from the board with the diodes and MOSFETs on it (the board with the smaller ones) and figure out which wires are the positive and negative power lines to the amplifier. Check the voltage on those, though with no data on nominal voltages it'll be shooting in the dark. Also, just curious... that metal tab on one of the boards, you screw that down to the frame of the amp right? That's the ground reference for that board, so with it floating, it could cause the problem all by itself.

Since it's a discrete component amplifier you could simply replace every semiconductor and questionable-appearing part on each board, but that's probably overkill.
Click to expand...


yes that metal tab is attached to the metal frame of the amp I did see a broken part of the wire on it so I soldered it back together. But the amp still blew around 8 days. I will see what I can do about testing them. This might be over my head.

Thanks
 
2000XJSPORT said:
I might try that. Just don't want to destroy the sub. It is an 8 inch sub, same as the one found in TJ's.
Click to expand...

Wait! TJs have a sub woofer mounted in the spare tire? The spare tire that mounts on the OUTSIDE of the vehicle?
 
Andy Steiner said:
Wait! TJs have a sub woofer mounted in the spare tire? The spare tire that mounts on the OUTSIDE of the vehicle?
Click to expand...

What I am referring to is the one mounted under the TJ rear seat. It was a factory option in the accessories catalog. Same Amp and Sub just mounted in a seat instead of a tire cover.
 
This is a similar problem to what was going on with my old 1000w amp. I replaced some bad soldering, still no better. I replaced a good portion of the capacitors on the board with new ones and it worked fine till I sold it.
 
2000XJSPORT said:
What I am referring to is the one mounted under the TJ rear seat. It was a factory option in the accessories catalog. Same Amp and Sub just mounted in a seat instead of a tire cover.
Click to expand...

A friend of mine just purchased an '06 Unlimited, and the factory sub is mounted in the center console. What appears to be an 8" speaker faces the drivers side, right below the belt. We have to figure out if it has a little amp on it, or if it was powered by the stock head unit, which has been replaced. The previous owner had a box in the back, because we found RCAs and the power-signal wire, along with a beefy ground wire curled up under the rear seat. No power wire, though. When it warms up we're going to pull the console and see if there's an amp under there, and see what we need to do to get it to operate.
 
No luck yet with this problem. Anyone have any ideas? I might just take it to get fixed. Anyone know of a good place in the Chicago land area?

Thanks in advance
 
I've had home Hi-Fi equipment fixed by a local TV repair guy, and he wasn't expensive, either. If there's an old time repair shop, they could do it, or recommend someone who could. Go to Best Buy, to the Geek Squad desk, ask if they know anyone that would be interested. Just a thought..
 
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