When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I can't stress enough... great write-up, but my god was this **** painful.
I replaced all the caps, resistors, mosfets, etc and I got my bass back! I also got a lot of static noise which i can only attribute to my lack of soldering finesse only worsened by breathing in solder fumes for about 10 hours.
In short, I love DIY projects, but I'd highly discourage anyone from trying this if they have minimal experience with electronics repair (I made a circuit board in tech ed in 7th grade).
Many thanks to Newsome79 for this thread and for all those that are participating. I'm foolish enough to dive into this one and see if I don't break it all. I figure if I do, well, I can probably buy replacements and try again. My rear amps and my driver-side door amp had been failing lately, requiring more and more power to turn on, so I knew the caps were going.
I'll reiterate what others have said--this isn't the easiest board work I've ever performed, although I'm very much an amateur. The board needs a lot of heat in it if you're using a fine tip. I've been using kapton tape to protect the other surface mount pieces as I go along, which may not be necessary but I'm clumsy. Technique is to use my iron at 800 deg F, place it on the joint, use my hot air set to 800 deg F to warm the joint area and board. When the solder flows, I use a solder sucker to empty it. Once it's mostly clean, I use the iron and a pair of tweezers to move the component post clear of the via. Took a while to develop this technique and before that, I ended up lifting a pad on one of the MOSFETs by accident by being a bit too aggressive with my wiggling of the component. Thankfully that pad is still connected!
One other note--one of the components (C16) from the list provided (and updated in this thread a time or two) by Newsome79 were showing as not just "backorder", but NLA on Digikey. I replaced it as noted below. It's a bit different in form-factor but seeing as how it's all by itself on the board, I don't expect a problem with fitment. Here's the list of everything I bought. Some of the parts were on super-backorder and took like nine months to arrive from Digikey. Note that these prices are not accurate, I just took the existing list and updated it.
(Paste this somewhere with fixed-width font for better readability)
Well its been a minute since anyone has attempted this.
It appears you are correct Panasonic has quit making that part or a replacement part for that 1uF cap. Also the part number you used UMV1H010MFD is also obsolete. Here is a short list of replacements on mouser or digikey.
Good Luck if the amps were not damaged beyond repair you have a very good chance to replace these caps and FETs and basically restore the Amps to like new response. Possibly even better. If not I still think I have all the parts in a box somewhere.
A website I have found useful in my career findng obscure and obsolete electronic parts.
Ah, the man himself. Thanks for the info. I haven't tested the MOSFETs that I pulled off, but I'll do that. Hopefully they're fine. I was thinking of using thermal pads on top of them to contact them against the aluminum shield, rather than using a paste of any sort. Any opinion on that idea?
I didn't notice that the replacement part I'd chosen has also gone obsolete, and I see the same "Long lead time reported on this product" message on all the options you posted. What a wonderful world, where it takes months to get simple components!
The parts i posted may have long lead but they also have current stock so lead time is just shipping time. I would still use a non conductive paste and polish up the metal surface that touches the FETs. The best of the best is CPU grade Thermal Grizzly Kryonaut or ProlimaTech PK-3 Nano Aluminum. Basic stuff i use for power electronics at work is100300F00000G from Aavid Thermal. https://www.digikey.com/products/en?...00F00000G&v=59
I also noticed in your photos that the BOSE Sub amplifier had the BOSE 121661 Pre Amp Equalizer chip. Those chips are normally on the Door Speaker amps not the sub amps. I mean maybe they are the same thing. The sub amps normally have the 131454 chip in that location. Interesting find.
The parts i posted may have long lead but they also have current stock so lead time is just shipping time. I would still use a non conductive paste and polish up the metal surface that touches the FETs. The best of the best is CPU grade Thermal Grizzly Kryonaut or ProlimaTech PK-3 Nano Aluminum. Basic stuff i use for power electronics at work is100300F00000G from Aavid Thermal. https://www.digikey.com/products/en?...00F00000G&v=59
I will follow your lead, good sir. Any comments about what kind of hot glue I should spooge over everything when I'm finished up? [Edit: nevermind you already commented on that in your first post.]
Originally Posted by Newsome79
I also noticed in your photos that the BOSE Sub amplifier had the BOSE 121661 Pre Amp Equalizer chip. Those chips are normally on the Door Speaker amps not the sub amps. I mean maybe they are the same thing. The sub amps normally have the 131454 chip in that location. Interesting find.
Oh no, he saw my work! lol
I wonder how many variants there are in these amps then. I haven't pulled off the door amps yet but will post pictures when I do as well.
Okay, it's been a while but I finally got around to replacing all the components on the subwoofer amps. Now, uh... is there a way I can test this thing to make sure it's functioning correctly? I can tell the difference when I plug everything back in but, well, it isn't exactly an epic difference. I kind of forget how bad the original Bose system sounds, perhaps?
Before I did the repair, I'm pretty sure it wasn't working at all--I would just hear a pop from the rear when I turned on the car. Now it's not popping, at least, but is there a possibility it's not fully operational? I did test all the MOSFETs and they seem to be functioning properly.
@Newsome79, you had mentioned that if I had a dead MOSFET, that I'd probably need to replace the 131454 Bose chip. One of them isn't testing well--when I apply power to the gate, the drain reads zero after a quick flash of voltage, while all the others seemed fine and actually showed voltage on the drain steadily below 1V. Is there a possibility that one of the boards is working and the other is dead? BTW, are there two speakers in this "subwoofer" being driven separately by L and R channel? Would seem odd, but I mean, there's two boards. I imagine that if there's two speakers and one isn't working, then yeah, this gimmicky, tuned waveguide setup might not be as "impressive" as it is supposed to be?
edit: Oh, and i have a bench power supply and a multimeter and that's it, but if I need to go get a spec an I will.
01-03-13, 11:06 PM
Note that these prices are not accurate, I just took the existing list and updated it.
