JL Audio 500/1 repair - guide?

mooch91

Member
2013-03-24 12:57 pm
All,

Asking to see if there is a quintessential repair thread for the JL Audio 500/1 or other slash series amps? That is, one that identifies and provides solutions for common problems and issues with these amplifiers? I've seen some suggestion that such a thread exists on the Internet, but I've been unable to find it. I could use something like this to start reading to see what I'm up against...

Here's the situation that exists with my 500/1:
  • Power light is always lit. None of the warning lights ever light up.
  • On some occasions, there is no or low output through the subwoofer. Moreso when the temperature is cold than warm. It's becoming more and more frequent.
  • Traveling over a bump, or providing a quick slap to the amp, will usually restore output.
  • At times, there has also been a faint scratching sound coming from the subwoofer when bass output is quiet (I've noticed it while tuning). Turning the amp off and back on usually resolves this, at least temporarily.
  • Also at times, touching any of the switches on the amp (EQ, crossovers, etc.) sends a significant "thump" out through the subwoofer.
I know these amps are challenging beasts, but I wouldn't shy away from a repair if it's a simple one (loose/broken solder connection).

I know the $180 JL repair is an option, but I've had such bad luck paying for electronics repairs in the past that if I have to go this route, I'd probably just end up replacing it.

Thanks in advance!
 
From the problem you describe it sounds like the inner socket of your RCA connectors has spread and is not making a good connection to the pin of the RCA cable.

A easy way to check that is with the bottom cover off plug in one of your RCA cables to one of the RCA jacks. Then take your DVM using the ohms function in low range clip one lead to the pin at the end of the RCA cable and the other to the lead coming out of the socket of the RCA jack going to the board. Move the end of the cable attached to the RCA jack sideways and up and down while watching the meter readout. It should remain stable and measure only about 1 ohm or slightly more which really is just the resistance of the leads. Some meters you can short the leads together and zero out the meter canceling the resistance of the leads.

If it changes more than a few tenths of a ohm there is your problem. You will have to tighten the inner socket of the RCA jack to make a good connection or replace it. You can also check your shield on your cables which can cause the same thing. Good luck with it.

For other posts just do a JL Audio 500/1 thread search, there are several.
 
The headers get bad connections on them. If you lift the preamp board about 1/16th inch and push it back down at each header 5-10 times, it should clear it up. Do not lift more than about 1/16th of an inch because the pins could pull out requiring that you disassemble the amp completely. It could also bend the pins which makes it more difficult to get back together.
 

mooch91

Member
2013-03-24 12:57 pm
The headers get bad connections on them. If you lift the preamp board about 1/16th inch and push it back down at each header 5-10 times, it should clear it up. Do not lift more than about 1/16th of an inch because the pins could pull out requiring that you disassemble the amp completely. It could also bend the pins which makes it more difficult to get back together.

Perry,
Any pictures available to help me understand a bit better?
Thanks!
 

mooch91

Member
2013-03-24 12:57 pm
From the problem you describe it sounds like the inner socket of your RCA connectors has spread and is not making a good connection to the pin of the RCA cable.

A easy way to check that is with the bottom cover off plug in one of your RCA cables to one of the RCA jacks. Then take your DVM using the ohms function in low range clip one lead to the pin at the end of the RCA cable and the other to the lead coming out of the socket of the RCA jack going to the board. Move the end of the cable attached to the RCA jack sideways and up and down while watching the meter readout. It should remain stable and measure only about 1 ohm or slightly more which really is just the resistance of the leads. Some meters you can short the leads together and zero out the meter canceling the resistance of the leads.

If it changes more than a few tenths of a ohm there is your problem. You will have to tighten the inner socket of the RCA jack to make a good connection or replace it. You can also check your shield on your cables which can cause the same thing. Good luck with it.

For other posts just do a JL Audio 500/1 thread search, there are several.

Easy enough to do once I get the amp removed.

Can the top cover on the slash series be removed with it still installed? I don't have it here in front of me to know...
 
The connectors are highlighted in orange.

The second photo shows the contacts mentioned in a previous post. This isn't a JL connector but it's similar.
 

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mooch91

Member
2013-03-24 12:57 pm
So I'm hearing two possibilities, both seem easy enough to investigate.

The preamp board connects through a pressure-fit connections. Moving the board slightly at the connection points "cleans" the connection. (Sorry, never had one of these opened to describe this better, just from what I'm hearing and seeing in the pic you've sent).

The RCA connections could have weakened.

I suspect the former more, since I don't get any change by wiggling the RCA cables/connections themselves when the problems present themselves.

I hope to have the amp out in the next few weeks for a complete re-wire of my system. At the very least, I am planning to reconfigure the installation to allow for the amp to be removed easier in the future (bolting up through the carpet of the vehicle as opposed to screwing down from above).
 

mooch91

Member
2013-03-24 12:57 pm
The headers get bad connections on them. If you lift the preamp board about 1/16th inch and push it back down at each header 5-10 times, it should clear it up. Do not lift more than about 1/16th of an inch because the pins could pull out requiring that you disassemble the amp completely. It could also bend the pins which makes it more difficult to get back together.

Following up...

I recently removed and reinstalled the 500/1 amp. I tried the above procedure, very easy to do once the cover is taken off the amp. So far, so good - amp has worked flawlessly since. It was flaking out about once a week before, and I haven't had an issue since (knock on wood) - even with the weather having gotten colder.

Thanks!