Hi Simon,
As others have implied, the DEC8235 is a Signetics 8235N. It's available
from obsolete part distributors. A quick search turns
up this source:
http://www.4starelectronics.com/part_detail/8235N.html
While the RFQ instead of a price is bad news in some places, I've had
good results with that in the obsolete parts arena.
is there a list of equivalents for DEC ic's?
--- Thought I had a longer list somewhere but this short list is what I
find at the moment:
DEC# Generic
----------------------
97401 7401
8881 7439* Quad 2-inp NAND OC
8266 8266 Signetics 2-inp 4-bit wide mux
8270 8270 Signetics may = TI 74178 according to posts in cctech.
8271 8271 Signetics 4-bit SR in 16p pkg = TI 74179
8251 N8251N Signetics BCD/decimal decoder in 16p pkg
5380 SP380 Signetics
5314A SP314A Signetics
8640 DS8640 National
380 (?) SP384A Signetics Quad 2-in OR gate
*Note that some DEC8881s have been reported as having 7439 markings on
the bottom.
Steve Lafferty