Fried Kenwood KDC-2008

[azzfox]

Hey all, Iv got a serious problem. I think I fried my mates Kenwood KDC-2008 H/U.
My mate wanted me to switch H/U's around in his Torana. I noticed that on the connector/plug that plugs into the back of the H/U had a few wire strands hanging out (looks like H/U plug was pulled on), but i just put some tape over them. We got it finally all wired up with the H/U resting on the floor. When I picked it up the back of the H/U sparked then started to smoke from inside the unit then stoped working. I have checked fuses. What could have happened and what could have possibly fried? Seeing it is an old model could it be fixed cheap? BTW the smoke smelt like gunpowder!

[Snotty]

weird, thought it would have trippped a fuse first..
If you can open it up you can probably see the damage

[StoneX]

Usually it will be the internal amp or protection diode/s betwen the 12v and ground in the unit. The internal amp is more likely to make smoke though.

The amp IC's for another brand are about $50, so Kenwood's might be around that plus an hour labour or so.

[garfa]

hehe a mate fried his h/u. dumb arse didnt pull off the neg batt lead.

[phat_com]

open it up and take a look
that happened to my mates H/U and the bit where the plug with all the wries on it connected to the board was all black and melted

[azzfox]

im not a newb to dismantling electronics but i cant figure out how it comes apart. the unit doesnt have a detachable face but i got the front off and cant figure out what to do next... has anyone done this b4? i can take sum photos if it helps.

[StoneX]

Usually the top comes of first.

[azzfox]

iv got it apart... but there doesnt look like anythin is burned out??? but there looks like big capacitor near the rear has white stuff aroun the bottom. is this normal and what else should i be looking for?

[azzfox]

the smoke came from inside the back of the HU. is the amp the big thing on the back of the HU?

[StoneX]

The white stuff is probably glue holding the cap in place.

The amp will be behind a heatsink... Usually it is on the rear of the unit.

[azzfox]

i ended up pulling the circuit board off because i had to to get to the screws for the internal amp and discovered this on the bottom of the circuit board. it has definatly burned out and im hoping that this is my problem. does anyone have any suggestions on what i should do about it eg. solder it back together. thanx.
here is a photo of the problem.

[azzfox]

and btw, would anyone know where i could get a new wiring harness? seeing the one iv got now was the cause of all this.

[MBS206]

Seeing how you melt a whole track, that is printed on (not soldered on) I'd be quite worried how you got that much current through there. Search for the cause before fixing the problem.

In all seriousness, go and buy a new, cheap headunit. Throw the old one away, they're normally not worth fixing.

[azzfox]

the wiring harness had wires exposed which my mate diddnt care about even tho i said that it was unsafe. and one exposed wire touched the H/U. that was the cause. btw, my mates a tight-arse lol and doesnt want to buy a new one but hes also not the richest. also btw it looks and feels like very thin copper and there could be a slight possibility of soldering it back together. any other suggestions ppl?

[mouce]

If you're really careful with the soldering iron, it is possible to bridge the gap with solder, or even a piece of wire.

That said...I take no responsibility if you do this and your car burns to the ground.

It takes a lot of power to strip a track from a circuit board, and with that much power flowing through one of the tracks, I wouldn't mind betting that a few of the more delicate components have had a hard time.

[azzfox]

i will give it a go soldering it. i have had a fair bit of experience with soldering (famous last words) but i dont know what it will turn out like. wish me luck...

[azzfox]

i think it was a success. maybe tomorrow i will take it back to my mate and see if we can get it to work. soldering that little piece was VERY time comsuming and fiddly. its a bit messy but its really hard to get something so small smooth and not lumpy.

[StoneX]

See where I have circled... It looks burnt there too, rub the coating gently as it will crumble away then reconnect that too.

When repairing burnt tracks, it is much easier and neater to cut the broken track completely away and link from one point to the other with a bit of wire.

Did the rear fuse blown when the magic smoke escaped?

Usually when the earth tracks blown, the amp IC has gone aswell.

[azzfox]

just finished soldering it and cant find anymore burned tracks and no the rear fuse diddnt blow. and what do you mean by IC? its probably somthing iv heard a thousand times but cant remember.

[mouce]

Having a closer look at that image, just up from the blue circle in Stones image (well...up and left a bit), it looks like another part of the coating that's been heated. Should check that out just to be safe.

[azzfox]

is it the part in the green cirlce your talkin about?

[MBS206]

The area where the wires connect to the board is heat affected.
There's another spot high up to the right that looks slightly affected (But it's away from everything else, so could just be a hot joint)

If it doesn't work. Throw it out. Headunits area bitch to fix when a track lifts or breaks

[mouce]

Yep, that green circle is the one I was on about. I was just too lazy to put a sexy little circle around it.

[StoneX]

IC is Integrated Circuit, a single component with lots of other components inside it. That's what the head unit amp will be.

[azzfox]

SUCCESS!!! I really had a doubt about it working but this time luck was on my side.

THANX Heaps for EVERYONES HELP!!!