JL 500/1 - issue w Input Settings/LP Filter

I have a JL 500/1 Rev 10 that was working very well when I got it in 2008. It has been sitting for a few years since until I recently tried installing it in my car.

Here are the issues I am trying to resolve:
- When I toggle the Signal Sensing switch to "On" the LEDs flickered briefly (I know I saw the the Low Ohm LED, unsure about Thermal) and then the amplifier shut off. I was using a suspect line-out converter but I was wondering if the flickering LEDs were consistent with the change of switch state. When the Signal Sensing switch is "Off" there was sound from the subwoofer - however it was only higher frequencies and very inconsistent (again suspect LOC.)

- When the LP Filter is set to 24db slope @ ~175 Hz there is no subwoofer output. This was a problem I recognized years ago so I did my filtering from the headunit.

- Tapping on the LP filter switch (iirc there was another switch too) or toggling the LP Filter switches would directly cause a thump sound in the subwoofer on contact with the switch.

- Battery drain. Every now and then the battery would be slightly drained and my vehicle wouldn't start lickity split. The previous vehicle's battery had excessive battery acid gunk on the + terminal after the 500/1 was installed. Is there a common cause for slight battery drain over time?

I have found this thread about adjusting the pre-amp board which seems to share a few of my issues and I will try that tonight. http://www.diyaudio.com/forums/car-audio/232688-jl-audio-500-1-repair-guide.html

P.S. there is a small piece of cardboard under the pre-amp board? It's slight stuck in there.. what is that?
 

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muchomango

Member
2016-03-11 3:42 am
Ahh, I was wondering what happened heh. Thank you for cleaning that mess up.

I wanted to add that the first pic attached in the above post is my amp guts. There is no obvious component failures. I listed all of my symptoms (which probably all stem from the pre-amp board) to see if there is any root cause commonality.
 

muchomango

Member
2016-03-11 3:42 am
Two questions/clarifications:
1) Should I have the boards removed from the case prior to this adjustment? It seems like they will not easily budge and I don't want to force it.
2) Is there any sort of feedback I should notice, or am I simply just wiggling the pre-amp board up and down?

Thanks!
 

muchomango

Member
2016-03-11 3:42 am
Perry, thank you!
I was actually just about to post these same pictures of the pins for anyone else who might be troubleshooting this.

While I was wiggling the board up and down, I did hear and feel what could be the oxide buildup - kind of like a scratching sound. Now the pins slide with ease.

About to reinstall and see if things are back to normal.
 
Update: reinstalled the 500/1 and sure enough - everything works great!

The LP Filter works again and there is no thumping on contact with the switches.
Edit: wanted to add that piece of cardboard ended up getting wedged under the pre-amp board again. I am not going to bother with it.
 
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