0 would indicate door open.... no optical connect.
There is supposed to be a constant pulse.

The intent of the pulse was to thwart cheaters.... people would pick the locks and open the door.
This would usually set off an alarm (silent) if the proper code had not been entered into the player tracking system by the security dude changing out the cash box or hopper contents.
The hack would be to simply use an IR light pen to blind the optics that the door had been opened. This kept the candle light off, kept the back room computer at bay, and the thief could swiftly empty the cash box.... coin would not be an easy or lucrative theft as you need a ton of it to be worth something.

To thwart this, IGT did two things.
1. Put a lock on the cash box door.
2. Moved to a specific pulse modulation of the door optics.

The first was to slow the thief down. If the door closed without the cash box the candle light would flash for service and picking a second lock would take time.

Once again I am no expert on the self tests so I am not sure if this is the correct behavior or not.

I am no expert on self tests..... but Are they working properly
- it seems to sit at 0... more than 1 .... I think it should be alternating between the two evenly....

Kevin / Mark ... perhaps chime in here.

I can video just it sitting at 13 0 without opening the door.

I found this document, photo on the forum (I don't know who it belongs to, apologies). It helped me understand the motherboard, where the plugs go, just in case some fool moved them around before I started working on them.

I have all of the S+ downloads, everything, and the wiring schematics, which are very difficult to figure out.

You changed MPU as well?  Did you try using another VGA cable?

Hey Rick, thanks for the response.  I did switch MPU's as my prior MPU (300mhz one) would not clear NVRAM no matter what.  It just fails every time and would not boot ever again after the first fail... so I bought a replacement 1ghz MPU from Spin and it cleared no problem.  I'm using the matching clear to the bios/os (got from RB).  However, when I switched to the newer OS, it does this split screen thing. I tried a different VGA cable and still does this weird screen off-set. 

I started with AVOS00000336-11 and the screen was messed up, so I went backward to AVOS00000336-09 and still messed up.  If I go back to 05, I believe it's OK, so why would it do this on the newer OS versions?

Quote from: David Walz on Yesterday at 06:39:16 AM

...I thought this rogue wire may be the problem, it's located under the play button...

There's 2 more questions you need to answer.
See Reply #218

Your video need to be put in the library!

https://youtu.be/PiR_xcFUN7Y