JL Audio 500/5 Low Ohms Light?

[rhempz01]

I have this jl audio laying around the shop, so was wondering if anyone knew of why it has a low ohms light on when you power it up.

 

[Perry Babin]

Have you checked for shorted output transistors?

 

[rhempz01]

Checking them now perry. Just got it cracked and removing these lovely clips I like so much.

 

[Perry Babin]

1. You can check them with the clips in place.

2. The clips are very easy to remove. If you're struggling with them, you're not using a good tool.

 

[rhempz01]

None are shorted. Some just read open

 

[rhempz01]

It acting something like a Rockford when the bias pots are turned up to much.

 

[Perry Babin]

Are you powering the amp up directly from the 12v supply? JL amps typically won't start through a current limiter.

 

[rhempz01]

Found them perry they were not shorted out just diodes. Found them on diode test

 

[rhempz01]

Picture is unrelated to the outputs sorry. Changed the post. I found some of the output on diode test to only read .009v some reading .01, so I pulled one and put it in the transistor tester, reads as a double diode

 

[rhempz01]

Had all different date codes of outputs in the channels.

 

[rhempz01]

I think I read somewhere the amp will not switch unless I jump something in one of the circuit, to trick the amp to thinking the outputs are installed. Just want to check the drive before I install new outputs.

 

[Perry Babin]

What are the markings on the 'transistors' that read as double diodes?

You can only check the drive for the class D circuit with the outputs out of the circuit.

 

[rhempz01]

Irf540, and ok ill remove them all.

 

[rhempz01]

will this amp still show drive with all of them removed?

 

[Perry Babin]

Drive? Where?

With all of them removed? All of what?

 

[rhempz01]

rectifiers out?

 

[rhempz01]

Will the amp still show the drive waves with all of the outputs removed? and do i remove the recifiers as well?

 

[rhempz01]

So I removed the outputs and tested for drive signals. Sub channel has drive. The two front and two rear channels has this

 

[rhempz01]

Q202 pin 1

 

[rhempz01]

The amplifier had multiple date codes mix matched in the sub channel and other channels as well. I'll be replacing them all. My question is do I turn the bias all the down when I replace them? Or leave it where it is?