Need help on old parts??

From: Dwight Elvey <elvey_at_hal.com>
Date: Tue Sep 5 18:36:57 2000

ard_at_p850ug1.demon.co.uk (Tony Duell) wrote:
>
> No. Please don't wire-AND normal TTL outputs -- it won't work properly
> all the time. It's marginal (and can damage the TTL chips involved).
>
> There is an open-collector 4-input NAND in the TTL line. It's the 7422
> (yes, I had to look it up). You could use one of those, along with a 2k2
> (or thereabouts) pull-up resistor from the output to Vcc. Don't ask me
> where to find a 7422, though.

Hi
 Looks like the 7422 is what I need. I was thinking
this myself. The spec sheet I got says that it has
an internal 2K pullup. The other part also has this
so it should work without an additional resistor.
I can always add one but I would exect it will be
more than fast enough for this old machine.
 I hope I can get to my local surplus shop before they close.
Thanks
Received on Tue Sep 05 2000 - 18:36:57 BST