Bally 6-digit display: the decoder chip should be E-620-38 (4543)
On Bally and Stern 6-digit plasma displays the decoder chip carries Bally's number E-620-38, which is a 4543 (MC14543) seven-segment decoder. A chip marked E-620-33 is a 4049 buffer and doesn't belong there. Before fitting a new decoder, check the display glass: if the small dot near the lower corner doesn't glow at power-up, the gas has leaked out and the glass is dead.
These displays run at about 190 V; keep fingers off with the game on.
Systems
Related tips
- Score display shows only a few numbers in display test: failed decoder chip
- Bally 6-digit display: one segment out on every digit, find the bad driver by swapping
- Bally 7-digit display misbehaves wherever it is fitted: replace the decoder chip
- Same digit missing or stuck on every display
- Bally score display looks gassed with good voltages: replace its 4543 decoder chip
- Bally and Stern score display boards
- How a Bally display board drives its glass
- One digit missing on a score display
Source: Pinball Repair help group!! (Facebook group)