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Yes these boards will be for cherry mx switches
I believe the 542 keyboards work in reverse of the 600 keyboard were the bit is set when key is pressed

I am starting with the keyboard. Follow Here:
viewtopic.php?f=3&t=433

/Jeff

Hi Guys,

I need some advice. It's time for me to order a bunch of IC's for the boards in my C4P Replica. Many chips are designated non-LS in the Sams documentation. eg 7474 or 7417 or 7400 instead of 74LS74 and 74LS17 and 74LS00. I know LS means "low-power, schottky". What is the difference? Should I substitute LS parts? or order non-LS parts?

Please advise.
/Jeff

I have use ls parts in all boards and have not noticed any problems, you wont find non ls parts as easy.

MK14HAK wrote: ↑Tue Aug 28, 2018 9:58 am Is the Cherry MX key the same footprint as the original OSI key. ie do they fit the original 600 and UK101 board ?

Sadly, no. The MX switches have different solder masks, and alignment holes.

Jeff wrote: ↑Sat Mar 30, 2019 6:27 pm Many chips are designated non-LS in the Sams documentation. eg 7474 or 7417 or 7400 instead of 74LS74 and 74LS17 and 74LS00. I know LS means "low-power, schottky". What is the difference? Should I substitute LS parts? or order non-LS parts?

The LS parts will almost always be a good replacement for the originals. They have similar propagation times, the same voltage thresholds, and lower power requirements, so your machine will run a little less hot.

Dave

Thanks Grant and Dave.

/Jeff

A bit late, but...

TTL LS works as a replacement for TTL especially if all chips are LS. However TTL can source & sink 2x as much current as LS series, so for things like bus drivers in a loaded C8P, you may be better off with TTL. LS can't drive as many TTL gates when mixing families.

Here is an old Nuts & Volts article describing the different families, and some more detail can be found in ON semiconductors description of TTL & TTL LS families. Generally I use whatever I can find in my parts box (mostly 'LS).
-Mark

Good Info!

Thanks, Mark

/J

Some of my parts arrived, so I built up the 582 backplane board.
/Jeff