What kind of board do I have in my S2000

[lowlimitlootlane]

See pic attached to help identify the board. Backstory... I wanted to get stereo sound, so I purchased the Multimedia Lite Board II for the machine. When I plug the soundcard into the board and turn on the machine I instantly hear a static noise, usually associated with a bad ground. Before I plugged in the soundcard there was no static, and only sound coming out of the right speaker. When I hit spin, I can audibly hear the humm from the reel motors the duration of the spin. I found a video on youtube that shows the issue I am having and how he modded his board to solidify the ground connections on the PCB. My issue Is I don't have the same board, I don't know what board i have, and am looking for schematics on how to reinforce the ground connections to get better sound in stereo. Any help in identifying the board, or offering wiring solutions would be appreciated.
Here is the youtube video i was referencing, https://youtu.be/NE-8_tUSy2s?si=egLdwgAl_TlWehoQ&t=178

Pics of my board attached.

[sixcardmark]

Machine probably has a mono sound harness and is most likely a 502 board that needs the sound ground mod.  It also needs the blue varta battery removed asap.  Member lookes repairs and mods these boards.

[lowlimitlootlane]

As far as removing the battery, does it need to be replaced or can this just be removed? Thanks for the information.

[sixcardmark]

Just remove, not needed for home use, will destroy board when it leaks.

[lookes]

You have a 500 REV D board. Useless for enhanced audio. One of the very first S2000 MPU's.
Is it stereo with the enhanced board? Need to know if you have a stereo wire harness and a top box amplifier.

The normal 502A audio rework won't work on 500's or 501's. It's meant for 502's   I do have a rework that makes 500's and 501's almost as quiet as 504's tho.

[lowlimitlootlane]

I do get stereo when I use the Media Board, but am getting that heavy noise out of the right. If no media board is used, sound comes out of the right, but there is no static noise. Here is a pic of the harness and amp.

[lookes]

Sounds like you are all set. You need to either get that board reworked, or get a reworked 502A or a 504B.
That Varta has to be removed. Looks like damage has already been done.

[lowlimitlootlane]

Varta battery has been removed. Sent you a PM about a board rework Lookes.

[lookes]

OK. This board is done. The corrosion was not serious. Cleaned up nice.
The audio noise was 'terrifying' lol with the MML2 board. As expected for a 500, or 501 board. This board is a 500 REV D.

I made sound level tests on this board with and without the new rework I have, as well as a random 504B board.

The background noise level in my shop is about 31 dBA. I measured the levels at 3 inches from the right speaker.
'Before' is without any modification. 'After' is with the rework. 'Random 504B' is just a handy 504B board for reference.
Remember that a 10dBA difference is double the apparent audio volume, or half the volume depending on which way it goes.

While booting:
Before - 62dBA   After - 49dBA   Random 504B - 42dBA

Reel Spin Noise:
Before - 81dBA!  After - 60dBA   Random 504B - 60dBA

Booted and at Idle:
Before - 62dBA   After - 47dBA   Random 504B - 53dBA

Tested with sound volume set at zero.  The volume of the background noise is unchanged and unaffected by the volume number in settings. The noise level is the same with the volume set at 0, or at 10. The noise enters through the power rails on the digital potentiometer chip on the MPU. Noise is introduced via the 5v supply voltage, and ground level fluctuations. Also some of the noise is inductively coupled from nearby traces. Most of the static you hear (not reel spin noise from the stepper drivers) is related to SENET signal activity.

[lowlimitlootlane]

This is beyond thourough, thanks for taking the time. Will PM you for payment/shipping. Thanks John!

[lowlimitlootlane]

I just got the board back and installed... wow. Let's start with shipping, when it arrived it was packaged so well, there was 0 air cavities, the whole board came cradled in bubble wrap, foam, peanuts, the deluxe. This was my first impression, and I couldn't wait to get it in the machine. When I plugged the board in and did a little RAM reset, the game came to life. There was stereo sound. It was brilliant. Yeah i still hear a little hiss as mentioned in a studio environment, but add some tunes and some conversation and you have a great little casino environment at home with the s2000 playing loud and clear in stereo. Just wanted to say I was thoroughly impressed with the work done and highly recommend it if you have an older board. Thanks lookes, bravo!