Replacement for a DEC 7474 Chip

Rob Jarratt robert.jarratt at ntlworld.com
Sat May 14 12:11:32 CDT 2022


Hello,

 

I have found a bad DEC 7474 chip on my M7133 board. Clearly it is a
74<something>74 D flip flop. The problem is I don't know which modern series
would be the best one to replace it with. I am sure I have seen a list
somewhere of modern equivalents for some DEC chip numbers, but I can't
remember where.

 

If it helps at all, on the PDP 11/24 printset it is E78 on page K6 of the
schematic (p157 of the PDF).

 

Picture of the failed chip here:
https://rjarratt.files.wordpress.com/2022/05/damaged-dec-7474-4_li.jpg

 

Can anyone tell me what the best modern equivalent is likely to be?

 

Thanks

 

Rob



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