Pengo IC74/U74 Replacement

After getting a bootleg Pengo PCB there was one small problem with it.. The board was missing IC74 !

The missing chip is an Am25LS2519 which is an old, and odd, AMD logic IC that's pretty hard to find these days. It also looks like it was hard for the bootleggers to get back-in-the-day as the the other bootleg/clone Pengo's I have both had a plug in board for this chip.

The plug-in appears to be a full implementation of a 25ls2519 in standard logic. It's even labeled '25LS2519 substitute' and is total overkill, as Pengo only uses about half the functionality of the chip. 

Anyway.. to get the board working I needed a replacement. The function of the chip for use on a pengo board fits into just 2 IC's, or even just one GAL16v8, but that's another story.

The replacement board also works on an original Pengo as a replacement for IC  'U74'
Schematics, board layout provided at the end of the page, so time to build one....

Time for a schematic

click for the big picture


Only two IC's are needed

74LS174, which acts as a 4-bit latch with  data clocked in on the rising edge of 'CP' clock pulse.

74LS86 which provides the inverted/non-inverted output depending on the state of 'POL', polarity.

The schematic was designed to keep the PCB routing simple so it would fit on a single sided board that can be home etched.


What's wrong with this Pengo bootleg (?)

click for the big picture

The 25LS2519 substitute board from another Pengo clone
On to a PCB

Single sided board, bottom/solder side
size of the board is 1.7" x 1.25"

Assembled board

74LS86 left, 74LS174 right


Assembled board

Top view - White dot it PIN 1

Project Files

Designed using Cadsoft Eagle 4.16r1 

 rep_pengo_25ls2519_project.SCH  Schematics
 rep_pengo_25ls2519_project.BRD  Single Sided pcb layout 
 rep_pengo_25ls2519_project.PNG  1200dpi PNG template for the PCB
  layout, for use in photo-etching

Plugged into IC74 on the board

The board is now working perfectly as you can actually see the graphics.

It also works on an original Pengo as a replacement for U74


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