Were Fish's plans for a switchable or just frenzy on berzerk? I don't remember offhand....
Switchable. Here's Dave's intro about it:
ZPU-1000 + Adapter Bd. = Berzerk + Frenzy
Last winter I picked up a Frenzy that used a ZPU-1000 (Berzerk) CPU
board and a small daughter board. The daughter board contained the game
EPROMS and a few IC's. After reverse-engineering this board I started
thinking about the possibility of a daughter board that would allow
either Berzerk or Frenzy to be played.
[About 9 months later....]
I've finally finished building and testing my Berzerk & Frenzy adaptor
board and it works fine so now it's time to let the details out. The adapter
allows a Stern ZPU-1000 board to run either Berzerk or Frenzy. The game
selection is made by flipping a switch (and resetting); no ROM swaps or
cable changing is necessary. The adapter board is fairly small (5" X 2") and
contains two IC's (EPROM, PAL), some caps, resistors, diodes and connectors.
The adapter board requires very little modification to the ZPU: 2 IC leg
cuts and four wires tacked onto points on the ZPU. The adapter itself plugs
into the two connectors, J5 and J6 at the edge of the ZPU. That simple.
I will upload all the necessary documentation to Wiretap in the form of a
ZIP file. The package contains a schematic (B-size postscript), a netlist, a
BOM (Bill of Materials), the .BIN file for the EPROM (27C010), the JEDEC file
for the PAL (22V10) and assembly/installation instructions. Look for a file
called BRZ_FRNZ.ZIP. If you can't get access to Wiretap for one reason or
another, e-mail me and I'll send you out a copy of the zip'ed file.
If someone feels ambitious and wants to make a PCB for this, feel free.
I don't think there's going to be that much demand for it tho'. I built two
by hand since there aren't really that many connections.
I know the question 'Can this work on a ZPU-1001?' will come up eventually
so I'll say up front "I have no idea". I've never seen a 1001. If anyone
wants to send me schematics for it I'd be willing to look into it tho'.