Adjusting or Tuning the Altair CPU Card

[Grant Stockly]

Even if your CPU card works, it may not have the correct timing.

You'll want to check the two clock phases 1 and 2 on pins 22 and 15.


http://www.stockly.com/images4/080426-Pinout.gif

You'll want to make sure your card follows these standards:

http://www.stockly.com/images4/080426-Timing.gif
http://www.stockly.com/images4/080426-Waveform.gif

Someone wanted me to adjust a vintage Altair 8800 CPU card for optimal performance.

Sorry for not getting "good" pictures of the scope.

This is where it started. Phase 2 was too long according to the spec (To2). Keep in mind this card worked perfectly, but may not be stable or respond well to temperature differences.

http://www.stockly.com/images4/080426-Bad_Waveform_4144.jpg

After replacing the 4.7k R42 with a 4.3k resistor, it looks like this:

http://www.stockly.com/images4/080426-Good_Waveform_4145.jpg

[marty]

Hi Grant;
I think I have a similiar scope to your... Only your signals look a lot cleaner than mine,,, mine look like, They were in the rough Seas !!!! Yours are basically straight and mine are not... :confused: :confused: What's up ????
THANK YOU Marty