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repairing my amplifier

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=126463
Printed Date: May 12, 2025 at 5:39 PM


Topic: repairing my amplifier

Posted By: 201.034
Subject: repairing my amplifier
Date Posted: March 06, 2011 at 5:06 PM

Hello I am new to this site, I hope I can get enough help to repair my fried amp. Heres the background on the amp, Ive had it for about 6 years. Its a Hollywood digital amp, I believe they went out of business. When I got the amp it was already fried(I already knew it was bad to begin with) So I took it in for repair. $80 later its fixed and has worked fine for over 5 years. A couple months ago my younger brother got a hold of it and I'm not sure what he did to it but when I got it back It worked for about a couple days then it stopped working. I open it up And see 4 transistors and 4 resistors are fried. I order new parts and put them in, I go to turn it on and its the 4th of july inside my amplifier. I open it up again and see the same transistors fried(this time resistors aren't burnt) What the heck?! Im not an electronics guru but I do have basic knowledge of electrical circuits. (I'm an auto tech)

The parts were less than $10 so thats no big deal.
Parts I replaced:
4- transistors
4- 47 OHM resistors

When I go to power(in its fried state) it on the Green power light on the amp turns on and I can feel the subs producing a very small amount of sound.
posted_image
Fried parts are replaced and fried again on the upper left corner (4 transistors) Why are they frying again? Am I forgetting something? I will gladly post more pics when requested. Im just not sure of what to take yet.





Replies:

Posted By: 201.034
Date Posted: March 06, 2011 at 5:25 PM
posted_image




Posted By: i am an idiot
Date Posted: March 06, 2011 at 6:02 PM
The 4 resistors that you replaced should all be connected to 2 driver transistors.  The driver transistor that is connected to ground is probably defective.  Both of the driver transistors will also be connected to the at least 16 pin Pulse Width Modulation control chip.




Posted By: lspker
Date Posted: March 06, 2011 at 9:36 PM
Check your output Transisters, you will some of them are fried also.




Posted By: sparkgap 44
Date Posted: March 07, 2011 at 4:52 AM
< language=> if you have changed the load on the output stage ie ran the amp into destortion level or wrongly conected the out- put speakers you will have to replace all input pre amp cct same components as first time after this ie out put driver tranistors then the bigger out put stage ie looks a bigger part  will have a large heat shield ,some amps couple  via a tx trasformer to the load some use the speakers as a load ie impeadance + speaker in ohms /chassis   - ground mind current is carried by the car body always make shure you have a  good clean earth or the radiio will act as the fuse and burn up accross the load? id you use the correct fuse rateing for the amp all checks must be done b/4 reintalling 1 ground 2 fuse 3 output stage +speakering wireing  good luck .

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sparkgap 85





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