Data East, Sega, and late-model Stern Display ROM Jumper Info
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 Data East, Sega, and late-model Stern Display ROM Jumper Info
Many of the Technical Articles on our site contain information and directions involving electronics and circuit board repair. They are authored with the assumption that the reader has adequate experience and knowledge required to do the work being described. If you do not feel qualified, or are in any way uncomfortable doing any of the work described in any of the articles, then we strongly recommend enlisting the help of a qualified repair person or shop who can do the work for you. It may save you cost, time, and further repair work. We (Action Pinball & Amusement, LLC) are not responsible for any damage to you, your game, or your property, from doing any work on your game related to any of the articles listed on this site.
Some Data East, Sega, and late-model Stern pinball games may have shipped from the factory with TWO 2MB ROM chips used on the display unit. Updates to display ROM software may be available on ONE 4MB ROM chip, rather than TWO 2MB chips. When replacing an original TWO-CHIP 2MB ROM SET with ONE 4MB ROM chip, you must remove the jumper at location R11 on the display unit PC board, otherwise the replacement chip will not work. Boards with part # 520-5055-00 shipped with jumper R11 in place, and were set up to use two 2MB ROM chips in locations ROM 0 (U12), and ROM 1 (U14). Likewise, when replacing ONE 4MB ROM chip with TWO 2MB ROM chips, you must install a jumper at location R11, otherwise the replacement chips will not work. Boards with part # 520-5055-01 shipped with jumper R11 absent, and were set up to use one 4MB ROM chip in location ROM 0 (U12), and no ROM chip in location ROM 1 (U14). These modifications are described in Data East Service Bulletin # 38B. A jumper is basically just a wire that connects two points on the board. The points are labeled on the PC board- label is usually located inbetween the two points, or dotted lines will outline the two points as labeled. The jumper may be just a simple bare wire, or a wire with white ceramic around the middle of it, or may look like a resistor. For more details on jumpers and replacing/installing them, see our related Tech Article on Williams games by clicking here.  Programming your own? When combining the data from both chips into a single chip, data from ROM 1 (U14) is written into the lower half of memory in the single chip, and data from ROM 0 (U12) is written into the upper half of memory. If you're uncomfortable doing this kind of work, we recommend leaving it to someone who is experienced. If you know which jumper needs to be set or removed, and don't know a local electronics technician, try taking the board to a local TV/VCR repair shop- they can do the work in a minute or two and may only charge $5 or $10. |
