IGT Fortune 1 Draw Poker - short repair log...

[Sprout]

I'd asked for assistance in tracking down the schematics (thanks to badbaud & shortrackskater for their assistance!) for one of these I was gifted in a dead state, and wanted to pass along my findings in case they are helpful to others.


Unit appeared dead. Scrambled video, no sound. Pulled backup battery - could get coin-up sounds consistently - seems to be playing blind.


Screen looked like it had a sync issue, and had no recognizable images. Checked the horizontal/vertical sync. signals on the board - static, non-pulsing, so that circuit was clearly dead. After some poking around and tracing through the schematic, eventually tracked the signals back to the 74LS74 at C15 - good input, bad output, and the signal from this chip was involved in both the HSYNC and VSYNC signals downstream.


After swapping it, I had actual graphics, but significant corruption. Could make out portions of the cards and some text, but clearly not correct. This game board used 2102's for the color and video RAM (some versions use 2114's), so had 8 video RAM chips to rule out, since the color RAM seemed fine. In checking the output of each using my scope, I was able to see that A13 and A15 looked "funny" compared to the others. Similar, but clearly not the same. Swapped those two out, and was rewarded with a normal/correct image! Buttons are a bit flaky, and the hopper is struggling a bit at times (need to clean/lubricate), but at least it's alive again.

[Badbaud]

Good catch on the 2102's, a flaky output is normally your only clue.