Problem:
I got the amp and the sub hooked up and when I try to play music, the AMP gets really hot in a matter of seconds and the SUB does not work. Anyone know what may be causing this?


Setup:
95 EG hatch
Rockford Fosgate 900w Mono amp
Sony Explode 12" Sub 350RMS 1200 Peak
Rockford Fosgate 4 Gauge Amp kit
Some Aiwa headunit (not sure which one)

Side notes:

-At first i thought it was a bad ground because there was paint on the car where it is bolted down, so i sanded it down until i could see bare metal.

- The 4 Gauge wire is too thick to fit in the AMP so i had to cut some wire down to make it fit. I am thinking of switching to a smaller Gauge so that it can have a CLEANER fit.

- The AMP is used; bought it from a friend
- AMP lights up red ; I have been told it should be GREEN

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Ill get some pics tomarow if that will help in anyway


Modified by thrty8street at 10:35 PM 1/4/2005

 

Sounds like a burnt power supply transistor.

So you say it gets hot really fast how hot and how fast.

RF uses cheap mosfet transistors I could probably walk you through the steps to fix it yourself if your good with a soldering iron.

 

it gets warm in about 30 seconds

in about a min + it gets really HOT , not enough to burn out but its still really hot

Im not that good with a soldering iron but i could try

-OH and what the HECK is a mosfet transistor???

 

Do you know how to use a multimeter?

I am interested in knowing how much current you are sinking before I tell you how to tell which transistors are bad. Alot of current means a lot of heat which could hurt you.

The transistors outside the heatsink will get a LOT hotter a lot faster

Metal Oxide Semiconductor Field Effect Transistor = MOSFET

Going to bed now I'll recheck here tomorrow.
If your not sure of your skills with a soldering iron I would probably take it somewhere to get fixed.


Modified by nsxxtreme at 9:06 PM 1/4/2005

 

UPDATE:

Now there is a LITTLE bit of sound coming out of the sub, the sound is really faint, so much that you have to put your ear near it to hear it. The amp still heats up like usual.

I tried hooking up one of my old stock front speakers to the amp and the speaker just blew up LOL. I dont know what that means...

I got a small screwdriver and tried messing around with the GAIN but no luck at all.

I took the amp apart but could not find a fuse.


Here is the pics i promised ...

 

Here's the deal if you popped a 60 amp fuse then you just dissipapted 720W thats a lot of heat.

So since I doubt you have a current limiting power supply we'll have to come up with something else. Go buy yourself a 30 ohm 10 watt resistor. The exact value isn't important just not to much lower than 30 ohms. This will act as your current limiting device. This will limit the heat to about 5W. Now 5W is a lot but some of it will get distributed across the resistor and some into the transistors. I want you to put this resistor in series with the positive terminal. You could hook a multimeter up in series as well. The current should be limited to less than .5 amps. This is assuming a 12 volt supply.

Usually when you have a blown power supply transistor the amp will heat up if connected to 12 volts. Even if the remote wire isn't hooked up. So briefly hook up the amplifier to the power supply. I can't stress enough the briefly part. No longer then 6 sec. Now after you disconnect it from the supply you should be able to lightly feel on top of the transistor which one(s) get hot. Do not hook a load (speaker) to the amplifier. Also do not connect anything to the input terminal.

Now you should also be grounded when doing this because mosfets are very sensitive to ESD (electro static discharge) ie static electricity. You can hook a 1 meg ohm resistor up to a wire. Then the wire should go to the ground terminal of your house. The other end of the wire should attach to you. It's up to you if you want to do this, if you don't you take the risk of blowing more transistors.

Almost forgot the transistor your interested in are the large ones that are pressed up against the heat sink.

Just getting of work so I won't respond til tomorrow

 

Hey, I have not yet do the multimeter thing.

My friend and I where testing the system out today to see what works.

First we tried putting his sub to my amp and the sub would barely play just like mine used to do.

Then we put my amp in his car and it could not power his SUB, we also put my SUB on his AMP and my sub did work so we know its not the sub, so it must be the AMP.

Conlusion: Im just gonna get another amp and get some smaller wires maybe 8 gauge and call it a day, hope everything works out.

I would try to do what you told me to do but it sounds kinda complicated im just gonna return the amp i got and get a new one.

 

If you had the option to return it why would you want to take it apart?

Ask whoever you bought it from if there interested in selling it as is. I might be interested if the price is right.

Best of luck.

 

how can I return it with no receits? i dont even know at what store it was bought from. All i did was remove 4 little screws at the back of the amp to remove the metal cover , if you consider that "taking it apart"

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thrty8street &raquo;</TD></TR><TR><TD CLASS="quote">how can I return it with no receits? i dont even know at what store it was bought from. All i did was remove 4 little screws at the back of the amp to remove the metal cover , if you consider that "taking it apart"</TD></TR></TABLE>
I don't know I figured you had a way of returning it since you stated.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thrty8street &raquo;</TD></TR><TR><TD CLASS="quote">I would try to do what you told me to do but it sounds kinda complicated im just gonna return the amp i got and get a new one.</TD></TR></TABLE>

So if your stuck with it and don't want to fix it, interested in selling it?

 

lol oh yea i meant i was gonna return it to my friend who i bought it from.

yeah ill sell it, are you interested?

 

is that a power series/bd rf amp?