JL Audio 500/1No audio out unless I ground the output RCAs.

[RJohns777]

Hi, working on a JL Audio 500/1 amp. All the switches needed cleaning. Amp runs but I have no audio unless I ground the output RCAs. Not the input RCAs. If I ground the output RCAs, the amp runs normal. Any help would be appreciated. Thanks.

 

[TNT]

How do you ground the output RCA - to what ground?

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[RJohns777]

Power ground

 

[RJohns777]

I can jumper the input and output RCAs and it plays also. My power ground and rca ground are the same.

 

[Perry Babin]

Is your signal source grounded to the same power supply that you're using to power the amp?

 

[RJohns777]

Yes it is Perry.

 

[Perry Babin]

Confirm that you read 0 ohms between the RCA shield on the signal source and the amp's main ground terminal?

 

[RJohns777]

Thanks Perry, Yes 0 ohms between the RCA shield And amps main ground.

 

[Perry Babin]

Do you have another in the shop?

Have you tried lifting and reseating the preamp board to see if that helped?

 

[RJohns777]

I don't have another amp right now. Yes I've lifted and reset the board several times.

 

[Perry Babin]

What version boards do you have for the preamp and main board?

 

[RJohns777]

Both are Ver. 10.

 

[Perry Babin]

Without grounding the output, if you drive signal into the amp, do you have signal on the output terminals of U2 on the preamp board?

 

[RJohns777]

I don't know what happened. It all of a sudden started playing. Guess I'm dealing with a bad connection or something. I have two power supplies. I tried it on both and I have output. I'm gonna run it and wiggle some things around. See if I can get it to go back out.

 

[Rob663]

I have a 500/1 slash .with an input issue if rca wires are hooked up and amp is on the subs start to play a tone that gets louder and louder the longer rca’s are connected .so I unplug them no tone plays .so I tested to input terminals and they have no continuity between them on the ground and no conitinuity from either term to main board ground .amp turns on fine no protect or low ohm .changed rca’s still does it.i hook up a diff amp no issue so I know it’s not the so I know it’s not the source or rca’s .just want a few ideas before I open her up

 

[Perry Babin]

Please don't post in a repair thread that was started by someone else unless you are trying to help them.

Start a new thread if you need help with a repair of your own.

If you think this thread is relevant, include a link to it in the first post of your new thread.

 

[Perry Babin]

Please don't post in a repair thread that was started by someone else unless you are trying to help them.

Start a new thread if you need help with a repair of your own.

If you think this thread is relevant, include a link to it in the original post of your new thread.

 

[Classic car audio]

I have deleted my comment. I am a new member and can’t seem to create a new post yet. Sorry for the issue.

 

[Perry Babin]

email me if you can't start a new thread.
babin_perry@yahoo.com