'05 645 Logic 7 amp repair diy

[Eric93se]

So a buddy of mine has a cool 645 where just his front two speakers were running. I did a little reading and found about the water issue and saw the cost of a new amp and decided to take a look at it before coughing up big bucks.

So the fix is pretty simple. The amp has to be removed which involves removing the trim on the left side of the trunk, removing the amp which involves unplugging the two connectors. The smaller of the two connectors is the optical digital lines (try to be careful with them) that one just unplugs. The larger connector is a slide on/off style which requires a little strength to pull the connector to the side for it to unplug. To remove the amp there are two rails that are on the side of the amp that have to get pried out with a screw drivers and some pliers once the get moving. If you have bent pliers you can grab the rails and pry against the amp (won't hurt it). Okay once the amp is out there are 3 torx screws to remove, then the snap on clips on the side of the amp (7) use a flat head to pry them out. To get the heatsink off the amp you can use a flat head to gently pry between the heatsink and the lower portion of the amp. Okay once the heatsink is off you have access to the board, you have to clean all the oxide off the amp using a paint brush and denatured alcohol. Clean the old thermal grease off the transistors and off the heatsink side too. You will need fresh heatsink compount that is non conductive and non capacitive. You can use thermal past that everyone uses on computer CPU's like Arctive Silver Alumina or regular cheap thermal paste that is used in the electronics industry (ebay). So you also have to remove the fans, its just couple more torx screws (smaller bit). I missed that section the first time around, and holly cow was there a ton of oxide where the terminals are connected to the board. I was amazed at how well that all cleaned up with the paint brush and denatured alcohol. Okay so after everything is cleaned up you have to let it thoroughly dry out, I let mine sit overnight on the oil burner (water heater), it just has to be a warm dry area. When reassembling just dont over do the thermal paste, it will just make a mess. A thin line on the outer edge of the large transistors and a small drop in the middle of the smaller ones. Everything else is just in reverse order. Have fun trying to get tie down rails in place, a squirt of WD40 will help.

It looks like the subs under the seats on my friends ride are fried. I intend to build him a real sub but I will look into replacing the factory subs first. Anyone know the size of the subs under the seats?



I added a rectangular piece of formica to block a portion of the trunk vent next to the amp hoping to block any water from getting at the amp in the future. What I really wanted to do was to get a Conformal Coating, that is a dieletric spray that will protect the circuit board on the amp from growing oxide again, but I couldn't find any locally. If you get a conformal coating just make sure you don't get any on the transistor heatsinks (tape them off). Also tape off all electrical connectors on the outside and the two electric fan board connections.

Hope that helps you save $600+ bucks Its a pretty easy job too.


Update: Get a can of Deoxit 5% this is the best product for this type of work. Use an old toothbrush to scrub everything, repeat 2x.

[ragal]

Hey,

I Taked my amp out of the car now I'am at home with the thing...

And i opened the 3 torx screws but How the hell i get the cover open from the amp? i spend like 2-3 hours and 0% too open it i destryoed the case omg ,

TO you got any photos where i can open it and how?

Thanks in advance

[Eric93se]

Did you pop off the seven clips on the sides, one side has 4 the other side has three. Gently pry them out with a thin screwdriver. Then the cover should come off.

[Yorgi]

I think you should follow your own advice (as stated on another forum) and bring the amp into an electronics shop for repairs now that you finally got it out.

[ragal]

Okey, I will try it in the coming weekend

But i got a question , did you repaired your amp? becous u cleanen it with isopropanol & paint brush, becous maybe your amp was never damaged ...

In my 645 the rear speakers dont work.. only the left side the sub are blowing all time like in dis video at min 0:20 +:
[ame]http://www.youtube.com/watch?v=YMzAAkQQPRQ[/ame]




It's the amp for sure i think...


Thanks

Greetings from Berlin

[stella431]

Okey, I will try it in the coming weekend

But i got a question , did you repaired your amp? becous u cleanen it with isopropanol & paint brush, becous maybe your amp was never damaged ...

In my 645 the rear speakers dont work.. only the left side the sub are blowing all time like in dis video at min 0:20 +:
http://www.youtube.com/watch?v=YMzAAkQQPRQ




It's the amp for sure i think...


Thanks

Greetings from Berlin

Main reasons for a speaker for not working are due to faulty amps. You need to check your amplifiers.

[gillms1]

Can anyone offer any advice to removing the big connector? I can slide it (about half way) and then it doesn't seem to budge! Does it slide all the way, or you slide it a bit and then pull out??

[Eric93se]

You can use a flat head screw driver to do a little prying but you have to be careful because you can crack those connectors. You can also first try spraying some WD40 on the connector and slide it back and forth to work the lube into the connector. If you spray lube, make sure the optical connections are fully protected with tape.

If you want to go the extra step and spray the circuit board to prevent it from re-oxidizing and can't find a proper conformal spray, you can probably use a clear acrylic lacquer spray.

[gillms1]

Thanks, yep I was worried about being too forceful so thought I'd get some advice first. So is it supposed to slide all the way? or you slide it a bit and this should allow you to pull out?

[Eric93se]

You might be able to look closely with flashlight at how the grooves in the top of the connector flow. I think on this one you mainly pull to the side, and it kind of ejects itself. I'm a big guy and pulled pretty hard, I think in the end I inserted a flat head screwdriver in the plastic loop that forms from the part that you pull on, and gently pry.

[gillms1]

Thanks alot, I'll give it another go this afternoon!

Finally managed to get the connector off! Replaced the amp and my front channel speaker - and now my subs aren't working! Pain in the butt, guess I'll have to put my original amp back in!

Cheers for your help, the screwdriver suggestion worked!

[greg rsa]

thanks for the threads, went ahead and stripped out the amp from the 645 (no back speaker sound and back pdc audio) did not look bad untill outer cover removed. There was a lot of surface corrosion and general buildup on the board. Sprayed down with wd40, then used a toothbrush to lightly scrub the pc board and components clean. Used compressed air to give board final clean. Purchased heatsink compound from computer shop for the transistors touching the heatsink and re assembled amp. cleared block drain holes above amp. Put everything back together and now all working 100%.

Thanks

[645cruisetop]

Just wanted to say thanks to all as google brought me here when I searched for my 645Ci convertible problem with front speakers not working after going thru a car wash. As others noted, water got in the back left in trunk and the amplifier (DSP unit) had some minor corrosion, which I simply removed with electrical contact cleaner 7.99 at Canadian Tire, and a Q Tip. Works like a charm now. Takes some time to get at the amp and remove it and remove the Aluminum cover, but very satisfying to be able to hear people I call (and music of course). The one large connector came off when I sprayed some of the contact cleaner to help in sliding it sideways following the diagonal channels in the connector you can see.

Once you get the amp out, there are 4 clips on one side to pry off with flat head screwdriver and 3 clips on other side, plus you must remove the 3 small torx screws (2 at one end, 1 at the other) then pry off the Alum fin casing.
Buy some heat sink compound at the Source to put on the transistors- you'll see which ones as the trace of old compound will be on the inside of the cover and on the transistors though fairly dry.

Note while you have the felt cover off inside left side of trunk, make sure no leaves are in the area in frame where the drain tubes go down and pour a small bottle of water in that area to make sure it drains properly out to the driveway. Drain tubes should be holding together and fully connected.
Also make sure the wire harness is seated properly where the top of the trunk is- any water that runs by that area will enter the trunk if that rubber cover isn't flush with frame at top of trunk in water channel- that was my problem as it had come loose- actually had to tie the 2 pull straps down in the trunk by tieing wire to them then anchoring both straps into frame using one of those plastic straps pull tie things that ratchet tighter.

- - - Updated - - -

Thanks greg rsa, your post led me to delve deeper and remove the amp and remove its cover, and alas there was the white bits of corrosion on the pins near the fan that were quickly removed with Q Tips and electrical contact cleaner- and now she runs like a new one!!!! Yahoo, love it when a DIY works so well.

To others, see my post about some other things to watch for re drains and the wire harness plug at top of trunk outside of trunk seal contact point with trunk lid.

[sinadavani]

Hey guys,
I noticed that some of you are getting frustrated with this repair simply because there are no photos for reference. Good news, i will post all pictures for this repair very soon, as I have done this myself.

Thanks,
Sina

[s14b23]

Bs it won't fix it.
Most likely little CPU board flooded and corroded, that's why L7 is bad.

Big board is pretty bullet proof

[cparke]

[

Bs it won't fix it.
Most likely little CPU board flooded and corroded, that's why L7 is bad.

Big board is pretty bullet proof

It very well may fix it, if the problem is just oxidation and corrosion from water damage. I have exactly this situation right now, AMP works intermittently because the short these processes cause is intermittent and circuit protection mechanism switches the AMP on and off. Clean off the corrosion and it will be up and running back to normal.

The write up here was very helpful to me and exactly what I was looking for, but I would add when I showed the board to an electronics shop, they recommended using Electronic Contact cleaner and then WD-40 on the front and back of the board, and that should do the job. Going to try that this weekend!

[Eric93se]

Update: Chemical to use is a can of Deoxit 5% and scrub with an old toothbrush. Repeat this process at least 2x. Blow off with compressed air, you can let the chemicals sit for a bit like 20min,

Deoxit is superior because it will leave a layer of protection (which is what I wanted in the original post "conformal coating").