Lanzar Optidrive 400id amplifier going into protect

[Op4500]

I'm going to work on a busted amplifier for a friend, it's a Lanzar optidrive 4001D, protect lights up and it sends a low frequency on/off pulse to the subwoofer and that's all it does. I haven't tested it yet, but I'm wondering if anyone has documentation on it. I'm going to start by testing the 24 MOSFETS. The board has no visible burn marks or signs of stress, capacitors all appear normal and aren't a brand I typically see fail. I'm told this amp is only a year old and he said it's 4000w RMS. This thing is beefy as hell, never worked on anything with such a ridiculous bank of filter caps, it has 6 3300uF 100v capacitors, 24 35v 2200uF capacitors, connectors sized for 0 guage wire. This thing is a BEAST. Just looking for any helpful advice, I've worked on a lot of power supplies, a couple home amps and digital circuits but this is my first car amp.
Heres a link to a photo gallery,

[stj]

Re: Lanzar Optidrive 400id amplifier going into protect

the wattage is BS, it's probably no more than 400w sine.
those pinochio numbers are always used on car audio!

you have 2 parts to that unit.
the first part is a split invertor.
it steps the 12v upto probably about 30-60v in a 60-0-60 style output.
the second part is the actual amplifier.

start by checking the fets for shorts.
they are probably wired in parallel to a degree, so if you find a few that look shorted, remove them or lift one of the legs one at a time & re-test.

these type of repairs are easy, but slow.

[Op4500]

Re: Lanzar Optidrive 400id amplifier going into protect

It definitely has some bad FETs, tested 4 so far and 2 were shorted between all 3 pins. I posted a thread in the soldering board about it but I'm having a really hard time getting these MOSFETs out, using a 40w soldering iron and copper braid to remove them. Is there a better technique to do this? I broke the leads off one of them because I pretty much have to heat up each pin one at a time and pry it out very carefully. I have to remove all of them because each bank of 6 is in parallel from what I can tell, they all read as being shorted when in the circuit.

[stj]

Re: Lanzar Optidrive 400id amplifier going into protect

a pump is better than braid, because your probably getting the braid stuck as the solder cools.

a bigger iron tip would help

[Op4500]

Re: Lanzar Optidrive 400id amplifier going into protect

I got one of those little solder sucker bulbs from radioshack, it doesn't really work. Maybe one of those syringe type ones would be better.