From Ray Carlsen's description:
Code: Select all
U13/U25 74LS257APC or A or AN but not PC (alt MOS7708) LOGIC
Blank screen, less than 38911 bytes free at startup or "garbage"
screen. See U25 Note: MOS77xx series chips have a high failure rate.
U14 74LS258 LOGIC
Blank screen.
U15 74LS139 LOGIC
Blank screen
Does anyone know what modern ones you can use to replace these? I see on digi-key and Jameco SN74LS257BN and 74LS258BN but can't seem to find A or AN or APC. Are these compatible replacements?
Is there a list someplace that shows modern equivalents? I thought the important parts was 74LS257, etc. And that the other letters like SN for TI and BN for package type etc didn't matter. But apparently it does.
Thanks!