Subject: Memory Expansion
From: Ken Lill
To: Bally Alley Yahoo Discussion Group
Date: Monday, January 18, 2016, 10:00am.


Actually, I have found a way to reduce the parts count. Every part fits on a 
.1" standard prototype board. I found some boards on eBay that would be 
perfect for this. You will need to acquire some wire wrap wire for your 
connections as well as a wire wrapping tool. It will have a stripper that 
works without nicking the wire.

The parts list consists of:

1) PCB prototype board
1) 61(C)256 skinny dip RAM (32K x 8)
1) 50 pin (25 x 2) pin header
1) Power lead with a .45" square pin socket (either .100" or .156"
   centers, depending on your unit)
1) Pre-programmed GAL22v10 chip  (24 pin skinny dip) I need to supply this
   to you unless you have the means for programming it.
1) 50 pin edge connector to 50 pin socket ribbon cable assy. These are
   available through DigiKey.
1) current schematic
1) 24 pin .300" IC socket
1) 28 pin .300" IC socket
2) SPDT toggle switch
1) LED ( for a power indicator)
1) 4.7K 1/8 (or larger) Watt resistor.
1) 10K  1/8 (or larger) Watt resistor
2) 0.10uF 50V multilayer ceramic capacitor. Axial leads will be easier to
   use here.
1) plastic project box with the interior space of at least
    3 1/4 length, 2 1/2" width, 1" height.
1) 4.7uF - 15uF 10V(or more) electrolytic. This is recommended, but may
   not be necessary.

The GAL22v10 chip eliminates:

1) NXP 74hc00 chip
1) Philips 74hct00 chip
4) 1n4148 diodes
4) 1/8 watt resistors
1) 2n3906 PNP small signal transistor.

Ken