S2000 door open b issue

[Catalinafan]

Hi all need the brains here to help solve an issue with door open b message
I'll try to explain best I can
machine was working flawless before other obligations kept it shut down for around a month or so
I'm now receiving closure m / door open b message. I know the closure m is normal but door open b is not
this message appears at any given random time. During gameplay or even idling powered on
Sometimes over an hour then other times within 1-2 minutes
Here is a list of things I've tried
Belly door switch bypassed
Cash box switch bypassed
Door optics removed (connected through door switch)
Removed and cleaned and reseated all game proms
Replaced battery
Used clear ivc00224 chip and key 45
Reburned stepper prom
Checked every connection I can find

I'm really stumped on this and hope someone could suggest something to try

P
By the way I turned on machine just before starting this message and I looked up to see door open b call attendant without any contact or changes from anything Lol
Any help would be appreciated.  Thanks

[Sunrise Side]

Try changing the I/O card on the main door

[Catalinafan]

Sorry I don't have any spare boards or much of anything surplus for this
Is there something I can bypass on the board?
 
Wow I can't even take a picture right side up  shewwww now you see who your dealing with lol

[Sunrise Side]

You will have to get a board from a vendor here unless someone else chimes in with other things to check.

[Catalinafan]

Ok thank you I will look for one

[therockinelvis]

Check your MPU board. Look at the green VARTA battery. They leak often and ruin the traces under it and throws both of these codes. On the 502 and 504 boards we remove that darn battery as it is not needed for home use and only leads to trouble. You might get lucky cleaning it with vinegar, but expect to need a new board.

[Catalinafan]

Forgot to add that battery was removed some time ago
Guess I could test some traces around it

[Catalinafan]

Update....
After inspecting all main board,backplane,and I/o board connections I decided to pick up some crc qd electrical cleaner and try it on the main board. Somewhat dissapointing results after a $9 can of ''no residue cleaner" I was left with a board that was fairly clean to one I found in a mud hole
I then used denatured alcohol and it definately cleaned very well (recommend this over crc spray)
Unfortunately received same results.....
I then remember the ink eprom I didn't swap out was u46 stepper (just because I only had 1 27c801 and used it in socket u44) I cleared and reloaded u46 files and.....
As of now machine is working great  I've played 1000+ games ( testing purposes of course lol) and several door open close and power cycles later it seems to be working well
Just thought I'd share this info so anyone else may have luck with it.
Thanks to all for input and suggestions.  Sorry to be long winded just trying to be clear about what I have tried with and without success

[mikec200]

Curious about your QD cleaner experience.  I use the stuff periodically and cant say I ever went from a clean to even dirtier surface once I've wiped down after letting the stuff sit and dry.  Any chance there was a residue already on the board the solvents ended up releasing that made things worse? I've had a transmission control unit that was covered in tranny fluid that migrated up the wiring harness (it one of the oddest car issues I've ever seen and in this particular car under certain conditions it is actually a somewhat common thing) and that stuff got all the ATF off, that I dont think alcohol would have.  Not a rep for CRC or anything, just was interested. Wondering if maybe there was a build up of something like smoke from the board's time in a casino floor?

[Catalinafan]

First let me say I'm not bashing any product just giving my experience
That being said  the board and whole machine was very clean with only slight dust build up
The board was clean enough before starting I considered before and after pics but didn't see the need. Didn't expect and great noticeable difference.
I have worked in the automotive field many years and I have used hundreds of different from brake cleaner to carb and choke spray. Of course some works better than others but my experience was it did leave a heavy residue. I spot cleaned with crc and when I seen results I used most of the can trying to remove smeared residue
As the tranny fluid I have dealt with it quite a bit and it is thin and not extremely difficult to remove. Carb and choke, brake cleaner, ether... Will remove it very well
Just a side note on subject. I have a bally e2000 slot when I got it the handle mech was froze solid I found the rubber plunger had deteriated and turned to nearly tar. After attempting a few different products I found acetone (nail polish remover) removed every sign of goop when gasoline.goo gone and e few others did nearly nothing
I'll attatch end results after using denatured alcohol.
Second pic around removed varta battery. The only place that looked suspect from acid leakage  that's the only reason I decided to clean board

[mikec200]

Interesting, thanks for providing that further info on your experience. Acetone is another great solvent especially when  others wont work, just need to becareful with it because it does work so well and may remove more then you want. Xylol is another good one too, but same caution there as well. Brake cleaner and carb and choke cleaner I'd shy away from in electonic uses, but does work wonders on grimed up bits and tranny fluid.

[Catalinafan]

No problem just sharing experience and hoping maybe to help someone else out
I've learned an incredible amount of info from the great people here
Main goal was to explain all trials and finding that swapping out u46 seems to have solved issue
Why you ask?  Lol no idea. I'm in no way a tech just as my grandmother would say I like to tinker