It's just some general advice really. In my infinite wisdom, i decided to respray my amp to match the bodycolour of the car. Now, it's been reassembled, it powers up, but with a problem. I joined a car audio forum to see if they could help. This is my post:
So, that was the initial post. Some responses, but as it's a popular forum it's soon forgotten about and disappears off the first page.Dan can't ever just leave things alone 'cos he's an idiot and always ends up breaking things wrote:Idiot of the month award goes to...(def. me)
Now, i have a nice simple but decent sounding system in my car. I've got an Alpine HU with iPod interface, i've got 13cm JBL components front and rear, and a nice Infinty Reference Amp (7521A) running an Infinity Reference 12" Sub. It's a really nice sounding setup, and by far the best sub/amp combination i've had.
I had a pretty basic install-amp covered up and sub on show in the boot. However, i wanted to 're-do' the install. The first thing i wanted to do was colour-key the amp's metal surface to match the car's body colour.
So, armed with a screwdriver, i took my amp apart. I carefully removed the necessary screws/covers/wires, and i photographed every single step so i knew how thing's went back together and where they go.
One nice white amp later, it's back together-everything as it should be. However, although the unit powers up, anytime i try to adjust the levels (bass boost, mhz etc), the unit sparks at point of contact (e.g when the screwdriver touches the adjuster knobs). Now, it appears to be happening when the screwdriver touches the outercasing of the amp at the same time as the adjuster knob. If i get a tiny screwdriver and it only touches the adjuster, then it's fine. However, during playback with the system turned up, every now and again the sub will 'pump', as in just a random thud. Only lasts about a second, but it's doing it-which is annoying. Now, unless i'm being thick-it seems like an earth problem. But my GND wire is fine-it hasn't been distubed at all.
I wish i'd never taken it apart now, as i fear a new amp may be on the cards. Is there anything i can do to solve the problem? Is there anything i should look for on the circuit board or is it well and truely shagged??
Any advice (other than 'don't take your amp apart in future' lol) welcomed with open arms!
Now, the black wire inside the amp is connected as it was when it came apart. The GND inside the boot is fine. The only other thing i can think of is this:
In the pic you can see these little black square thingy's (i don't know what they are). They are sitting on some rubbery paper thin strips that look like plasters. One plaster thing was midly 'nic'd' when i was prising the black square things off. However, it wasn't like crowbar prising, it took a 0.5mm flathead screwdriver to just 'ping' them away from the strips. They were stuck onto the strips with something, but not alot-maybe just some spray adhesive? When i put the amp back together, i bent them down ever so slightly, so they would press up against the case to ensue a good contact. As the rest of the circuit board is intact, no 'chargrilled' marks anywhere, i'm thinking this may be the cause. I'm just wondering in the mean time wether anybody has had any similar experience or could give me some things to test at the weekend. Two audio centres have told me that most of the time amps are just dumped 'cos it's cheap enough to buy a new one. I've seen mine again from a dealer, but it's still £80+, so it's money i don't have.
Anybody any ideas/advice?
Oh, and the pic...