Jan 062016
 

Recently got this Final Star Force PCB with graphical glitches on the sprites.

fstarforce1

This game uses a motherboard (pictured above) and has a romboard on the other side fitted with no other chips than the game’s ROMs.

All the ROMs were tested ok on my programmer and cleaning the connectors and looking at the signals, everything seemed fine with that romboard.
The motherboard has a rather simple layout with a lot of RAMs, some ASICs and a few TTLs. After a few hours looking for suspicious signals, I finally found the faulty ones.

There is a row of 12 Sanyo LM33464G RAMs (64k-word x 4-bit). Two of them were bad (the ones at IC22 and IC33). Piggybacking them with new ones partially brought back clean sprites, even if there were a few glitches remaining. These glitches totally disappeared after replacing the RAMs.
As these models of RAMs are a bit uncommon, I took compatible TMS4464 as replacement (highlighted in red):

fstarforce2

Here are before and after pictures:

fstarforce3 fstarforce4

  2 Responses to “Final Star Force repair log”

  1. Nice repair! I would suggest looking into the game Riot! from NMK. Its a cool unreleased game that plays similar to Cabal or Nam 1975 on identical hardware. It is a direct rom swap with FSF 🙂

    • Thanks ! Indeed I bought the PCB with that in mind. I already swapped the games, it works flawlessly. 😉