audiopipe1800d protect problems

[ghettorabbit6]

k so i have an audiopipe 1800 that i purchased used on caraudioclassifieds.org when i got it it was working fun and have been using it with no issues what so ever for about 4 months running in at 2ohms with voltage never under 12v. then one day i had to run extended leads to my 12" re se because when i installed the recone from fi i put the leads to tight all 4 broke so after adding some extra length to the leads that night i was listening to my amp and the lights in my car dimmed really bad twice then the amp sent almost like a hz test tone threw the sub. after that i shut off my stereo to turn the remote off to the amp and when i got him turned it back on to see what had happend when i did so the amp turns on and goes in and out of protect very rapidly and makes a clicking noise. i took the board out to see if i could visually see if anything was wrong but nothing looks burnt at all. im asking what could cause this on caraudioclassifieds i was told "and this kinda makes sence" that my leads could have been long enough to slap and touch each other.


here is a pic of where the clicking noise is coming from.

Having A Protect Problem - SMD Forum - Page 5

pics down at the bottom.


if anyone could help me fix this that would be fantastic. thanks in advance for advice and opinions

[Perry Babin]

It sounds like the output transistors failed. Post a good quality photo showing the entire board.

[ghettorabbit6]

thanks for such a fast responce i took 4 pics one of the whole board then close ups.

k here is the whole board.



http://i56.tinypic.com/1tkk5v.jpg



and here are the 3 pics of closeups

http://i54.tinypic.com/2ldzqit.jpg
http://i52.tinypic.com/2ih5e6r.jpg
http://i52.tinypic.com/bewv7k.jpg

[Perry Babin]

There are 5 transistors on the heatsink on each side of the amp on the end near the RCA jacks. With no power applied, measure the resistance between the legs of each individual transistor. Do any read near 0 ohms?

If you haven't done so, you should read the basic amp repair page (link in sig line below) in its entirety.

[ghettorabbit6]

i did read it but i figured i should post as well. i dont have a DMM right now i gotta wait till tomorrow to get one but tomorrow i will do so and post up results. again thanks for ur help.

my other question is if a whole bank of them is bad or even if just one is bad could those going have blown other things on the board as well?

[timwebb]

i got two of these bad.

[ghettorabbit6]

in testing them it seems like all 10 are bad. in testing different parts of the legs all went down to almost 0

[Perry Babin]

Find the ones with the lowest resistance between leg 1 and the other 2 legs for each transistor. There are likely 2 (one on each side) that read near 0 ohms. The others will likely read near 20 ohms.

[ghettorabbit6]

ur right the last 1 on the end twards the red wires on each side are the ones reading close to 0 all the others are around 60. this means that those are the bad ones correct?


if im right i think the last one on each side has shorted. because when i test with my dmm to see if theres a path between the 2 " has a sound function beeps if there is a path" there is with the last 1 on each but not with any else.

[Perry Babin]

It should not have read 60 ohms unless the gate resistors are greater than 10 ohms or unless the gate resistors are out of tolerance. You also need to confirm that the 10 ohm resistors connected to the first leg of the failed output transistors is within tolerance.

Yes, those two are shorted. Clamp all transistors tightly to the heatsink. Place the shorted transistors in place (not connected electrically) so that you can clamp the adjacent transistors, if needed.

If none of the gate resistors for the remaining transistors are out of tolerance, power it up through a 20 amp fuse. If it doesn't blow the fuse, see if it will produce clean audio. If it does (don't drive it too hard), you need to replace all 10 of the output transistors.