by RameGoom » Thu Dec 09, 2021 5:07 pm
Jennings 400s are problematic. The original NICAD battery on the logic board will leak, and acid damage will leach into the circuitry, under the ICs and in the solder joints near the battery. Corrosion is a real problem with this design.
The logic board was pre-microprocessor, so there is a blend of early CMOS and TTL on the board. The factory jumpers and modified traces are there for different games as they used basically one logic board for several games. The edge connector at the back of the board rack should be looked at - alignment of the board to the edge connectors can fail and give you fits.
The power supply is a monster analog supply that will frequently give you low voltage problems. Check those voltages. I have dozens of them rebuilt on the shelf if you need one.
I had 30 of those machines that I sold to a movie production company who used them for props, and have rebuilt several of the 400s and 700s over the years. Lots of work to get them going, but once they work, they are consistent.
They didn't use polished aluminum on the interior of those machines, just cad plating, so no doubt the plating is gone on the base. Sand blast it and rattle-can the parts to restore.
John
Slowly building a knowledge base on E2000 series Bally machines and J400 Jennings. Started with the antique Mills and Jennings. Getting there...