Repairing MTX 1501d - Help a newb - diyAudio
Go Back   Home > Forums > Amplifiers > Class D
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Class D Switching Power Amplifiers and Power D/A conversion

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 18th January 2009, 04:25 PM   #1
diyAudio Member
Join Date: Nov 2008
Default Repairing MTX 1501d - Help a newb

So I finally got the cajones up to try to fix this smoked mtx 1501d I got scammed on.

Replaced all the 75339 fets (all shorted out) and a couple melted poly caps right near them.

There's also a cracked (looks like physical damage) diode I replaced that leads to the fet in the center of the board.

I think the previous abuser of this amp "modded" it, since Q240 is missing.

So on first power up (no speakers, no inputs) I get the power led and about 3 seconds later LED238 near the input section lights up.

LED399 in the center of the large caps never lights.

Trying my test again with a speaker connected and an audio source. Soon as LED238 lights I get a very faint buzzing on the speaker. (About .1 volts on the dmm).

No idea where to go now.
  Reply With Quote
Old 19th January 2009, 06:03 AM   #2
diyAudio Member
Join Date: Nov 2008
Have you check the gate resistors ? I noticed most of the time when the mosfets transistors blown the gate resistors go to. Take your DMM and check all the resistors that are in front of the mosfets.
  Reply With Quote
Old 19th January 2009, 10:55 AM   #3
diyAudio Member
Join Date: Nov 2008

I should of thought of that. (I had to replace one on that 6100d I was messing with)

There two of them, and they're both open.

I'll have to see if I can clean them up. They're a little dirty from the magic smoke, as if they weren't hard enough to read to begin with.
  Reply With Quote
Old 19th January 2009, 05:26 PM   #4
diyAudio Member
Join Date: Nov 2008
I have that problem all the time man, if I cant see the colors on the resistors I just take the resistor number thats printed on the PCB and phone in to the manufacture and they will look it up in their service manuals.
  Reply With Quote
Old 22nd January 2009, 11:31 AM   #5
diyAudio Member
Join Date: Nov 2008
Does "39R2" sound about right? I got one clean as I could and can still barely ready it with a magnifying glass.

Is there a size to these little smd resistors? Last time I ordered SMD diode's, they were too small to even cover both solder pads.
  Reply With Quote
Old 9th May 2013, 09:25 PM   #6
diyAudio Member
Join Date: Mar 2013
Where can I find an owners manual for an MTX 1501D thunder elite
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
MTX Thunder 1501D spooney Car Audio 49 16th July 2010 04:55 AM
mtx 1501d sawtooth waveform Speeed3 Car Audio 53 1st July 2008 08:28 PM
IC3120 (split from mtx 1501d ) calebjoshito Car Audio 4 30th June 2008 02:44 AM
mtx 1501d ONEGGT Car Audio 0 18th October 2007 08:07 AM

New To Site? Need Help?

All times are GMT. The time now is 11:50 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2