mtx schematics?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=97253
Printed Date: April 28, 2024 at 10:33 PM
Topic: mtx schematics?
Posted By: dpaton
Subject: mtx schematics?
Date Posted: September 19, 2007 at 11:48 AM
I'm caring for a dead MTX 500D. MTX won't repair them any more, and doesn't seem to want to supply me with any kind of troubleshooting documentation to allow em to fix it. They're happy to sell me the parts once I figure out what died though.
I know I could take it to a shop and pay them to fix it for me, but honestly, I'm not interested in throwing any more money at this problem than I have to, and since I'm more than qualified to fix it myself (provided I can identify the issues), I'd like to try.
Any ideas?
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Replies:
Posted By: dwarren
Date Posted: September 19, 2007 at 12:12 PM
Have you opened it up and given it a visual inspection? Looking for burnt traces, mosfets, and or caps? I honestly have never tried to repair an amp, but I have opened many dead amps just to have a look and more often than not I can see a burnt or melted area, but i have also seen dead amps that appear ok as well. -------------
Posted By: swerve
Date Posted: September 20, 2007 at 1:54 PM
grab the multimeter and soldering iron, start desoldering the transistors on the edges of the board that attach to the heatsink and measure them out and see if they are still in spec.
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git yer swerve on!
Posted By: i am an idiot
Date Posted: September 20, 2007 at 5:25 PM
There is no need to remove the transistors to check them.
Posted By: dpaton
Date Posted: September 20, 2007 at 6:34 PM
I was hoping for something more helpful than electronics 101. Links to circuit information, troubleshooting guides specific to the amp, etc.
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This is not a sig. This is a duck. Quack.
Posted By: drvnbysound
Date Posted: September 20, 2007 at 9:14 PM
For starters, does the amp LED even power on? I have personally had an experience with 2 MTX amps, where the solder that holds the power connections to the board actually melted and caused the amps not to power on at all. I was able to re-solder the connections to the board and it worked fine.
Posted By: dpaton
Date Posted: September 21, 2007 at 12:40 PM
If you want the real nitty gritty, the LEDs are fine, but the speaker output is at the internal DC rail, around +60something volts at all kinds of current. It killed my 10W6 in seconds when it failed.
I have the talent to reverse engineer the whole damn amp myself, but I'd rather not spend a week or two of evenings circuit tracing, especially since I know I have blown parts in there.
I'm guessing from the number of views on this thread and from some other sites I've been to that I'm SOL. Yes or no?
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This is not a sig. This is a duck. Quack.
Posted By: kgerry
Date Posted: September 21, 2007 at 5:54 PM
as mentioned already, unsolder all the O/P FETs and test them ( i ALWAYS test out of circuit) then with O/P drivers out of one channel or the other power it up... you have to isolate the problem to one output stage or the other, OR the power supply.... if you are passing supply voltage i tend to suspect a shorted O/P driver.... (or possibly a pre-driver) visually check your O/P rail gate stopper resistors for overheating, this usually a good indicator of which bank of FETs is the culprit thats about the only advice i can offer without having it on a bench myself ------------- Kevin Gerry
Certified Electronics Technician
MECP First Class Installer
Owner/Installer
Classic Car Audio
since 1979
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