Good sources for obsolete part data?

[Mike]

I'm on a search for datasheets for some (obsolete) ICs. Some of these may
go back to the 1970s...

I've tried www.datasheet4u.com, www.datasheetarchive.com, www.alldatasheet.com
www.nteinc.com, the despammed data search at ef.algebra.com, www.digchip.com,
GlobalSpec ... but have now got down to parts that don't seem to exist

Direct Googling for part numbers throws up endless companies offering to
sell me these chips, some with the possibility of data if I agree a quote ...

I'm after any data search engines that would be able to produce data for the
following, or alternatively if anyone has a PDF around for these, drop me an
email/follow-up here.

UAA4001 SGS Thomson, Switchmode Chip
NS405-B18 National Semiconductor, Display Chip
MP3455NLL
D8202A DMA Controller
96LS488DC National, GPIB
COM7210 SMC, GPIB
F681488 National, GPIB
OMTI 20507 SMS/NCR
OMTI 20505 SMS/NCR
KT1135 Motorola Dual Baud Rate Generator
MA872
MA853
SL9045 Plessey
MA5036
SP620/A Plessey? Maybe DTL J-K FlipFlop
RCA16177
SAB8289A Bus controller/arbiter
MK5156J Mostek/SGS, A-Law Codec
TBA550Q Video Chip
TAA700 Video Chip
UA785 Video Chip
MCTM7817L
SAB3012