Hardware Hacking

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As part of the Hardware Hacking Challenge I thought that I'd try to resurrect a Pong game that I built back in 1978.  My intro blog is here: Pong Game Circa 1978

 

Since it came out of my junk box and seemed to be in poor condition I thought that I probably should have proof of life before I invested too much effort in restoring it.  I was somewhat surprised that the 30 AWG wirewrap wire that I had used had oxidized and become brittle.  Some of the wires were actually broken.  I still use 28 AWG wire of the same vintage and the unused wire seems like new.  I guess maybe the wire may have reacted with the metallization of the wirewrap pins.  Anyway, I decided I should rebuild the circuit from scratch - just reusing the ICs and the crystal.

 

So, I cut the circuit board out of the case (who used connectors back then ).

 

Top of the board:

 

  • Pong chip AY-3-8500-1 (-1 for NTSC)  Date code 7707
  • 4072 CMOS Dual 4 input NOR
  • 4001 CMOS Quad 2 input NOR (might be a 4011 Quad NAND - can't read the marking)
  • 2MHz crystal
  • 6.3V zener - I had used 9V batteries for power (I probably could have run the parts directly but the typical voltage for the Pong chip is +6V to +7V)

 

The bottom of the board:  You can see the blackened wire ends wrapped on the pins.

 

Switches and jacks viewed from inside the case:

 

To verify life I thought that I'd just power it up and verify the clock circuit and that the video sync and composite outputs were working.

 

2 MHz oscillator waveform:

 

Video sync:

 

Composite video:

 

So looks good to proceed.  Hope to have a functioning game soon.  I just realized that I'll have to scare up a composite monitor......