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http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Repairing_Alkaline_Corrosion

That is a capacitor and not a resistor.

I would carefully cut off the battery holder and inspect underneath for more damage.
Hard to say but there maybe something on U-52 too. Post a pic after you remove the battery holder.

Clays guides explain how to remove/repair acid damage. You could also just buy a new board and change it out.

It's working fine and it looks like almost no damage at all, so I miss your winking smiley after the last sentence.

Winking smiley??

I'm not sure what you mean. He asked for options. I gave him the best 2.

Yeah, you want to arrest the corrosion you DO have before it gets worse (i.e. gets into the traces). The good news is it looks extremely minor and should be easy to clean up.

This.

I just rebuilt a Sys80 MPU with some stout damage, get it cleaned up. If its working, great! No reason to replace the MPU. Get rid of the battery holder (remote pack or nvram) and neutralize with zep acid based toilet cleaner, stuff works great. $4 at Home Depot.

Agreed. I don't see anything that remotely warrants a replacement.

Not acid,
Alkaline damage.

Luckily, this is very minor damage and shouldn't be a very long or time consuming fix.

Hard to tell from the resolution, but it LOOKS like two pins at the right end of the chip at U42 are corroding, too. Maybe got dripped on? I'd check everything DOWN from the battery holder carefully.

On a side note, once you clean off any residual - install a NVRAM and be done w/batteries.

If you need to install a socket, find a local tech if you aren't comfortable w/desoldering a chip w/a lot of pins.

no need for this whatsoever, send it to someone like Rob Anthony and let him repair it, its not that bad but needs to be cleaned up correctly.

All the top pins on U37 are suspect, as is the little green (capacitor?) to the right of U42. I'd say on U42 itself, it's the SIX pins on the right, with the two closest to the center probably okay, but those 4 adjacent to the right end? Definitely.

Just neutralize what you can find and clean the acid off you use to do it. This thing is far, far from a difficult fix. Unlikely to even need to unsolder anything anytime soon.

+1 on the NVRAM or remote battery holder.

*Edit* If you don't know what you're doing, don't even think about working on the board with a soldering iron. Solder that's been corroded is harder to work with, and you're more likely to pull a trace when removing components. Battery damage and corrosion is one of the few things I recommend people use a tech for, and I've never paid a tech in the 7 years I've owned games (because I chose to replace boards..all the ones I had with acid damage were massively damaged across 40%+ of the board. Yours is VERY salvageable!). If you screw something up with poor rework, most techs won't even touch it at that point, much less the few that are actually good at repairing alkaline damage.

Start with vinegar and a soft brush. Rinse with distilled water.

If you're not happy with those results there is a thread here about using a strong acid, search around for it.

I have used vinegar and Zep, skip the vinegar and go right to Zep.

Ditto^^, but find the thread about it. I've done it, works well.

no, still needs cleaned and sanded to prevent future damage. just because you can't see, doesn't mean its not there. stuff seeps into all kind of nooks and crannies, you're eye isn't trained to see what a pro sees.

Use lithium. A lot less likely to leak. Cheap insurance.

With some soldering, the 6116 NVRAM will never leak and this one has 124 year retention rating. No insurance needed with it.

https://www.pinitech.com/products/6116_nvram.php