Burn U26 and U 27 with F1 software https://www.ipdb.org/search.pl?any=earthshaker&search=Search+Database&searchtype=quick
27256

download Fam Version open and extract u27_F1 and u26_F1

u26 is a 27128
u27 is a 27256

The F1 revision looks like it needs a 256 in u26 but it's merely just pre-doubled up the top half is exactly the same as the bottom half. If you only have 256's/only want to order one chip you could just burn onto 256's it will work fine in the machine.

earlier williams games like Pinbot and Taxi used a 16KB at U26 (27128)

Earthshaker Uses a 27256 at both U26 and U27 32KB

I think you mean "omits."

Williams released the new ROM before they went out of business?!

Curious.

That’s bitchin!

Yes, very curious.

Offended by the word 'bitchin'. They obviously have not watched tv or been in real life.

30 years ago people were always looking to be offended!!!

Not like when I was a kid 30 years ago!

Must be one of those arcades in the bible belt, or maybe Mennonite belt....

Where is your "Pinball Museum" located?

Gameseum in Ephrata?

I heard Otaku has some REALLY good repair guides....maybe read those or reach out to him directly.

That's fuckin bitchin

Dw5Sw3pWkAcdK38 (resized).jpg
Booger is worse than bitchin'!

It doesn't have to. There is a slight difference in the upper and lower half of the family rom that a cursory glance didn't reveal (I just looked at the first 30 or so bytes in each of the haves) so in the case of F1, yeah, you'll need 256 for both, at least until I look at what the 2 bytes differences are.

The actual romspace needed for earthshaker is a 27128 for u26, from 4000-7ffff, and the 27256, for 8000-ffff. I doubt there are any other system 11's that require the 256 for the bottom half either, as you'd neither need to modify the board itself to bank select it or there's very large gaps in the available addressing on the rom since the PIA's all live in that address space, along with the ram.

Just because a lot of the roms have been dumped and distributed incorrectly doesn't mean that's what's required.

UPDATE: According to pinmame the lower half of the ipdb version is the 'correct' one. One of the changed bytes is in the test data for the sound test (makes sense, since it says bitchin during it), and the other byte that was changed is in the default values for the self-healing switch table, which makes no sense at all (unless it was done for checksum correction)

Someone needs to go through the romsets that are around and figure out the definitive versions. I suppose the end result would be it doesn't matter if it's working correctly.

Put pieces of cut up sweatpants in the speaker holes to muffle the bad words. This will change the sound frequency from oh, bitchin, to metuchen.... like metuchen NJ. Plus, you need more sweatpants.