Fixing amps

[ejschultz 10+ year member]

So I have 2 amps that both do not work. Well, they're not actually mine, but as of right now, they're in my possession. My girlfriend's brother wants me to see if I can get them working. I have a decent electrical background; that's what I'm going to school for. I've never worked on an amp before. One amp, an Audiofonics or something like that will flash the protect light one time and nothing else. The other amp is a Lanzar Vibe and that just stays in protect mode. If anyone has anything that I should check out first, let me know.

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[modskwod 10+ year member]

PM db-r on here. He could probly help out.

 

[ThatChevyGuy 5,000+ posts]

those arent worth fixing, both are trash.

 

[ejschultz 10+ year member]

PM db-r on here. He could probly help out.

Thanks.

those arent worth fixing, both are trash.

I know. Try telling him that. Plus, I could use the practice.

 

[ejschultz 10+ year member]

The one amp is for sure an Audiofonics ADF-2843 2 channel amp. The other is a Lanzar Vibe 800 watt (so it says) 2 channel.

 

[dB-r 10+ year member]

Far too many possibilities. Best to send them to a shop.

 

[PIITB Wut Wut 10+ year member]

lol they are trash tho....

as long as their is no liabilty.... GO TO TOWN practice all ya want!

 

[JimJ 5,000+ posts]

Keep the heatsinks, drop the guts of decent amps in them, proceed to confuse SQ judges //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[ejschultz 10+ year member]

Far too many possibilities. Best to send them to a shop.

Thanks. Disregard the PM I sent you then...

lol they are trash tho....
as long as their is no liabilty.... GO TO TOWN practice all ya want!

I told him I can't guarantee anything. I'll probably take them to school with me and see if someone there can help me out.

Keep the heatsinks, drop the guts of decent amps in them, proceed to confuse SQ judges //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

LOL. This sounds like a good plan. Too bad I don't ever plan on competing for SQ. It's far too subjective.

 

[ejschultz 10+ year member]

Well, I had both amps apart hoping to be able to find a burned resistor or some other physical damage inside that would be easy to spot and fix. This isn't the case. Looks like I'll be taking it to school for sure and using test equipment there, and hopefully some other peoples' knowledge too, to see what exactly is wrong with them.

 

[smoka 10+ year member]

I used to intern at an electrical devices company and in my spare time I would bring in my friends blown amps to play around with. I learned a few things but its not easy to work without any schematics...

The only help I can offer, is to inspect the amp very carefully, most of the time you will find a burn mark etc where the amp blew. Also its usually one of the transistors that go first so check them well. If it is going into protect, I would guess its a short somewhere in the power supply. If you get the amp to turn on, but no sound. Use a signal gen as an input to the rca's to get a constant source, then use an o-scope to 'follow' the signal through the amp.

Again this is just stuff I found while playing around, not very technical, but good luck.

 

[ejschultz 10+ year member]

I used to intern at an electrical devices company and in my spare time I would bring in my friends blown amps to play around with. I learned a few things but its not easy to work without any schematics...
The only help I can offer, is to inspect the amp very carefully, most of the time you will find a burn mark etc where the amp blew. Also its usually one of the transistors that go first so check them well. If it is going into protect, I would guess its a short somewhere in the power supply. If you get the amp to turn on, but no sound. Use a signal gen as an input to the rca's to get a constant source, then use an o-scope to 'follow' the signal through the amp.

Again this is just stuff I found while playing around, not very technical, but good luck.

I checked for burn marks in both amps and found none. One of the amps goes into protect and the other will attempt to power up in protect mode then immediately shut off. I'll see what I can do once I get to school next week. My adviser has helped a couple of my friends fix their amps so I'd assume he'd be willing to help me too.

 

[dB-r 10+ year member]

Taking amps to school to fix is a great project for begginers, as the inerds of amplifiers is relatively "simple" to someone who is "old school" like professors are and if they have ANY experience with audio amplifiers they can figure out Class AB amps easy. Drop a Class D in front of them.... LOL they have no clue what does what.... once it's explained to them how it works they go "oh", well then, and proceed to help. But you have to know a few things or they may look confused. Class AB is easy though, the same stuff that's been around since transistors have been around, just different day, same shit.