depth charge 4004 amp problem
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=103316
Printed Date: May 08, 2024 at 6:23 PM
Topic: depth charge 4004 amp problem
Posted By: 944guy
Subject: depth charge 4004 amp problem
Date Posted: March 22, 2008 at 12:31 PM
Ok I was given a depth charge 4004 amp I was told it worked I had it hooked up at one time. Today I took it out to hook up my old setup a guy wonted to buy. When I rehooked up the depth charge the protect light went on but was flashing and the power light was doing the same thing but at alternate intervals. So, my question is what’s going on? The amp is pushing a 16-ohm load I already remade my ground and it still wont stop.
Replies:
Posted By: 944guy
Date Posted: March 22, 2008 at 12:42 PM
Also when the green light flashes the speakers push a note of like 5hz for a split second
Posted By: DYohn
Date Posted: March 22, 2008 at 1:08 PM
Turn the gain all the way down then try again to set it properly. ------------- Support the12volt.com
Posted By: i am an idiot
Date Posted: March 22, 2008 at 5:31 PM
The amplifier has a shorted output transistor. Or maybe 2.
Posted By: 944guy
Date Posted: March 22, 2008 at 11:30 PM
Is there a way i can send this to some one and get it fixed or is there a kit i could get to fix it myself if not any one got a full range and that can be briged to have about 40watts rms into a 16ohm load.
Posted By: i am an idiot
Date Posted: March 23, 2008 at 9:19 AM
Do you have a multimeter and tools to take the amp apart?
Posted By: 944guy
Date Posted: March 23, 2008 at 10:46 AM
yes i do
Posted By: i am an idiot
Date Posted: March 23, 2008 at 12:30 PM
I have never seen a depth charge amplifier so I will be no help in getting it apart. I need you to remove the bottom plate so you can see the circuit board. You then need to identify the amplifier section of the amp. Chances are it will be the end nearest the RCA jacks. There should be 4 identical looking sections. The larger transistors that are mounted to the heat sink are the output transistors. I need to know what kind of clamping mechanism they are held to the heat sink with. Screws and metal bars, spring clamps with a square hole in the middle of them? Set your meter to the diode test function. This is the symbol for a diode 
There are going to be 8 output transistors. Place the black meter lead to the center leg of a transistor and place the red lead to one of the other legs of the same transistor. Notice the reading. Then place the red lead to the other leg of the same transistor, notice the reading. Repeat this for all 8 transistors. One set of them will give you a much lower reading than the others. Let me know what you find out.
Posted By: 944guy
Date Posted: March 23, 2008 at 9:38 PM
il check the depth charge on Tuesday hey i have another amp thats blown i took it apart on one of the transistors bolted to the heat sink there is black mark and a hole blewn in it its one of the smaller ones two. its held on with screws and metal bar. is there a replacement i can get. its a mtx thunder 2301 class d mono block.
Posted By: i am an idiot
Date Posted: March 25, 2008 at 7:13 PM
If it has visible damage, chances are it is a power supply transistor. This will not be an easy repair for a beginner. Can you verify that it is a power supply transistor. See the large transformer, it should have at least 2 different colored wires wrapped around a circular core. Is the transistor located near teh transformer? Can you make out the number on it or the one next to it? The problem with the depth charge should only be the output transistors. If the MTX is a power supply issue, there could be surface mount resistors and transistors as well as the actual FETs that are shorted, 1 may be visibly damaged, but chances are all of them are shorted.
Posted By: 944guy
Date Posted: March 25, 2008 at 8:01 PM
hey if you dont mind can i have your number to just call you. Are you talking about two ring looking things with wire wraped around them? if you are the only numbers on them are T1 and T2. or if its something else just let me know.
Posted By: i am an idiot
Date Posted: March 26, 2008 at 3:34 AM
What is the number on the transistor that is burnt up. Not the board location number, the actual number on the case of the transistor. If that one is too burnt up to read, what is the number of the parts on either side of that one?
Posted By: 944guy
Date Posted: March 26, 2008 at 8:23 AM
ok so im gussing you asking about the MTX right. you wont me to find the number on the little chip thing thats bolted to the heat sink right? i will check it out when if i get home today.
Posted By: 944guy
Date Posted: March 26, 2008 at 3:02 PM
ok there are two things that look like there blown on the mtx they are bolted to the heat sink. there are two numbers on them here they are the first one is
D522AJ and right under it theres another number its
75339P
here is the next one
1450TB
75339P
also they are both on the right side of the amp one on top the other on the bottom.
Posted By: i am an idiot
Date Posted: March 27, 2008 at 12:46 PM
I am not familiar with those numbers at all. Can you tell if the middle leg of those transistors are connected to the transformer?
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