Whats really inside a Sega MC8123?

Dead Perfect Billiards MC8123A donated itself to science.

Desoldered the aluminium cover and bottom little pcb and magically appeared a black NEC MC8123A.

image

Apply some heat at the plastic ‘tub’ peels off.
image

Apply some more heat and the potting mix turns to rubber and can be chipped/peeled away to expose the little ceramic pcb holding the battery and a 3771 reset chip.

image

image

The bottom still has potting mix intact, so more heat and chipping away with a screwdriver reveals this.

image

Unfortunately the solder holding the legs on melted and they came off. All thats left is a ceramic pcb with what’s probably glob tops.

Unfortunately I don’t have the chemicals to dissolve this stuff and heat doesn’t seem to do anything to it.

image

I wonder why there are 6 solder points on the top of the pcb? Maybe a way to program the MC8123’s encryption ram?

Reverse Engineering Robotron on a bootleg Defender pcb.

image

This little pcb was created by Radich Electronics back in the day to convert a bootleg defender boardset into a Robotron boardset.

But where is the Special chip 1 pair you say? All the TTL logic above the roms implement the blitter chips. In a attempt to prevent copying they have sanded off all the identifying labels.. even underneath the chips!

Fortunately nowadays we have chip testers that can identify any TTL chips, so I am currently labourously desoldering and identifying each chip. Next step is to scan the pcb and make a net list to create a schematic. There are tools out here to assist with reverse engineering but they are all expensive, or require paying someone else to do the work.