Many good posts on this topic:

https://pinside.com/pinball/forum/topic/stripping-battery-corrosion-with-a-strong-acid#post-3554050

Acid has probably eaten away traces. I'd swap it for a rottendog card to get it up and running quickly and repair the original on the side. Or have it repaired by TNT.

There are a lot of board repair guys on here. I have one of mine over at Gameroom Service Jerry Clause.

I would recommend Chris Hibler. You can contact him via the pinside boards ChrisHibler or via his website chrishiblerpinball.com

Borygard barakandl johnwartjr PinballManiac40 all do board repairs.

robin Is there a Pinside shop category for repair services?

Edit:

Does Rottendog make one for SST? It's not in the game list for the MPU004. http://www.rottendog.us/MPU004.html

Pinside doesn't have a specific shop category since these are services, not sellable items.

But there are a bunch of Biz who do repair work listed here: https://pinside.com/pinball/biz/directory#mail-repairs

I second Chris Hibler. He fix my acid damaged white star CPU and it works and looks great. Plus he is a nice guy.

Folks...they are referring to the TNT Amusements in Ohio...not us in Southampton PA...We are officially TNT Amusements Inc. We have 5 phone lines of automation and can never have a full mailbox! (However, we no longer do outside board repairs on games not sold by us...we remain too busy). Todd

You're other option is to buy a new board BUT they are hard to find and expensive. Rotten Dog does not make a Whitestar replacement board but I wish they did. I'm not made of money and would have prefered to make component level repairs but.............

Here's my quick story. Researched for a month and made repairs that didn't work. Bought a new Stern board (520-5300-00) for $450. Game works perfect.

Long story:
Bought a Sega Xfiles, worked great. Took the CPU out to add second sound channel and found spider web of jumpers on back due to acid damage. Six months later CPU/Board began to give errors (mine seen in the DMD). I replaced the suspect IC (flip flop) after checking all traces and previous jumpers. Still no luck.

Statted calling local and far expert board repair guys. All had a back log (didn't surprise me 1 to 3 month wait) and, do to time and pricing, I decided to track down a backward compatible new board. I found a new Stern 520-5300-00 for $450. bit the bullet and bought it. Plug and play (4 chip swaps) and bingo, game is perfect. I asked a bunch of techs about buying a new board and they said "if you find one for $450 - buy it".

Edit: I'm not saying that the 520-5300-00 will work for you but you can ask Stern or the distributor about your Sega ST.

Sorry I haven't been on in a few days. You can email him at [email protected]