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**Reel Slots** Gaming Machines => **Reel Gaming Machines** **General Chat** => Topic started by: ramegoom on May 08, 2015, 06:19:24 PM

Title: Bally E2000 EPROM Questions
Post by: ramegoom on May 08, 2015, 06:19:24 PM

While troubleshooting a narrow body E2209-44 machine that threw a malfunction code, I discovered an odd checksum on a 659183 P1 chip ending with 20. Replaced it with a different P1 chip, now the CPU is fully functional. The P2 chip on this machine is a 000900. This slot, as I'm told by Barry at Foxslotts, uses unusual and proprietary EPROMs, no data available. I can find no reference to these EPROMs anywhere, as the E755 chips are numbered -64, -65, and -66. All of the E machines I have use -80, -47, -48 and/or -102 M chips plus various 2701 and 3701 P2 chips.

Trying to find a pattern with the data in the Bally EPROMs. After looking at dozens of them, I have concluded that, in summing the data, the checksums on each have a distinct footprint that can't be changed. I have reason to believe that any deviation whatsoever in those checksums will result in an error code, preventing power-up.

M1, M2, M3 and P2: All checksums end in 00 (least significant bits), so typical checksums would be AF00 or something.
P1: always ends in 56, typical checksum would be 2F56 or something similar.

EDIT: I did find one P1 chip whose sum ended in 60 instead of 56 and is fully functional on a machine I have. Now I'm totally confused.

Can any of you Bally experts shed some light on this?

Title: Re: Bally E2000 EPROM Questions
Post by: jancsi on February 07, 2016, 06:22:57 AM

Try reading it with lower voltage,it maybe help for you.
Put one or two  seriel diode to VCC  (it will drop 0,6-0,7 or 1,2 -1,4 Volt lower VCC  ) while reading eprom content.

Title: Re: Bally E2000 EPROM Questions
Post by: GOS on February 07, 2016, 08:18:06 AM

my documentation shows the 64 65 66 eproms are "DMI INTERNATIONAL - CUSTOM VERSION"