Car Audio Amplifier Repair

[beretta]

Does anyone know how to repair an amp ? how to test voltage regulator

Does the voltage regulator have anything to do with the amp not turning on ?

I think i just blew 60 bucks on a couple amps today, guy said they worked when he took them out, he bought new amps and sat these on a shelf for 3 years.

Rockford punch 125.2 Wont power on the voltage regulators are soldered to a metal strip that gets bolted to the casing and there is some melted solder around them but everything is still connected, nothing looks burnt and nothing has exploded.
(i got both end caps with this amp) pretty rare to see them still with these amps most people dont even use them and get lost.

My last amp was a 4 channel punch 300.2 maybe.. and i had 3 or 4 voltage regulators that blew apart in it.

2nd amp i got is a Pioneer GM-X962, i went to hook it up in the car to test it, i put the power wire on and soon as i touched the negative it popped both 25 amp fuses. i tryed it again with 10 amp fuses (all i had) and it popped them.
I stripped it down to inspect it and the board looks good except one spot, the solder was melted away from 1 point on the ground so i re soldered it and hooked to my battery charger, it draws hard on the charger and kicks it off so there is a short somewhere but i dont know what to test. there is no crossed solder points that i can see and no exploded caps ect.

I have a multi meter, but i dont know what to look for to test on the board.

Anyone ever worked on this sort of thing?

[beretta]

[ErichZ26]

I repair Chrysler/Infinity amplifiers that have blown power transistors. They are not cheap and there are different qualities and ratings.

[beretta]

i really have no clue about this stuff lol. im trying to learn so i can repair them and could repair others later on.

found this info online, the amp pictured is the same as my pioneer lol.

http://www.bcae1.com/repairbasicsforbca ... basics.htm

[beretta]

also just found this site for mosfets and circuits.. http://ca.mouser.com/Semiconductors/Dis ... 40&FS=True

[ErichZ26]

check the board for damage.

[ErichZ26]

http://www.bcae1.com/repairbasicsforbca ... basics.htm

[beretta]

all of the mosfets and stuff are good on the pioneer, i just looked up how to test them and they are all testing fine and look fine.

The problem is the power supply is shorting out somewhere, i thought it was a couple caps on the power supply side so i removed them but then they tested ok after removed, it still shorting without them in there.

There is 1 diode from the fuse + that feeds into the mosfets or voltage regulators but im not sure how to test the diode, supposed to have power hooked to the amp and check the voltage coming out of it. last time i tryed something similar i fryed my multi meter lol.

[beretta]

http://www.bcae1.com/repairbasicsforbca ... basics.htm

been here already it mostly talks about how to test the diode and fets, i dont have experience with power supplys and i dont want to fry nothing so im unsure how to test that part. im getting there though..

The amp in the pictures on that site is the same as my pioneer. it could even be the IC chips shorting out, im just getting into it trying to learn how to test as i go.

With just my battery charger that is 6 amps it draws the amperage meter to full on it and will kick the charger off after about 10 seconds then comes back on, none of the leads i can see inside are crossed, so something in a circuit is shorting, if i hook it to my car it pops the fuses in the amp so i assume the problem is after the output of the fuses.

Its one of these things circled in red lol.. the one with the ? is the diode i dont know how to test cuz you need to have power hooked up to measure it correctly (i think)


Im trying to figure out where the remote leads run to check on that circuit, maybe when the guy un hooked it he touched something and shorted it, he said it was hooked up working before he took it out

[beretta]

There are many different ways that an amp can fail but the two most common failures are shorted output transistors and blown power supply transistors (< those are not blown). There are several types of protection circuits in amplifiers. The most common are over-current and thermal. The over-current protection is supposed to protect the output transistors. Sometimes it doesn't work well enough to prevent the failure of the output transistors but it will work well enough to shut the supply down before the power supply FETs are destroyed.

If the amp remains in protect mode, goes into protect mode or blows the fuse as soon as the remote voltage is applied, shorted output transistors are almost certainly the cause.

Im going to start removing parts until i can hook power to it and it doesnt draw or pop fuses then ill know what part that was shorting lol

[berettaboi]

i'm an electrical engineering tech student, but only in my 2nd semester. still lots of sh!t to learn... yeah, need better pictures.

there's a bit of rust on the rockford's cover screws, that's a scary sign to start... but $60 aint bad if you can get one working for next to nothing.

[beretta]

i think i figured it out... i took all the output transistors off the board it was still shorting with power hooked up.
I was able to test them with the meter one by one, when they are in a series its hard to get accurate reading, if one was bad they would all read weird..

So i removed all the FETS (power supply transistors) they have 3 pins, you touch the 2 outside ones and its supposed to give me a high reading.. http://www.youtube.com/watch?v=Jzx8KeeK ... YHMPllLe3t

This video is confusing me a little though, he says looking for a short.. ( if his meter reads 0 then there is a short) if it reads high numbers the chip is good)... i think he means if there is a open short not a crossed short. there is supposed to be continuity between the pins not nothing at all

My chips are isolated so the metal part is not exposed so its not supposed to ground to the chassis in this amp, so i tested by the 2 outside pins.

These are all the same part numbers.. there is 6 of them, 1 read 900+ one was 34/45/50 ect,. all different readings none were the same.
Im going to order them and see what happens.

PS. without the transistors on the board i can hook power to it and no draw and no popping fuses, i think i found my problem.

Now onto the punch amp, thats the one i really want to use lol

[beretta]

LOL.. figures.. this site doesnt have any of these chips..
http://ca.mouser.com/Semiconductors/Dis ... 06&FS=True

they are MOSFET P55NE06

[beretta]

Found them, not the same but direct replacement. 61 cents each. if this works i might go pro on repairing them and find some free ones

http://ca.mouser.com/search/ProductDeta ... -STP55NF06

[ErichZ26]

I thought it was those. The ones for your aftermarket are cheap. The Chrysler/Mitsubishi Infinity ones are about $30 each and there are 3 in the Amplfier.