13 Dec
2003
13 Dec
'03
6:48 a.m.
Philip Pemberton wrote:
LC1552B / 7438 - looks like the main controller. Has
some strange logo I've
never seen before - kind of a _/- (a squared off S?) with a circle
printed over the top.
I have run across the LC1552 in another calculator (Digimatic M8-3) and had the same
question regarding the manufacturer logo. Another calculator collector told me it was an
early logo of Western Digital and that he had conformed this with people at WD.
ITT / 492-5 / 7445 - these appear to be LED drivers.
I've never seen a part
number like this. BTW, the "7445" is printed vertically, the rest of the
p/n is printed horizontally (as normal).
If those drivers are 75492 as Tony suggests, you can see an example of their use at
http://www.cs.ubc.ca/~hilpert/eec/calcs/CommodoreC110.html and click on 'view'
under 'TD23 Data'.
or
http://www.cs.ubc.ca/~hilpert/eec and select 'MISC ICs'.
NSA298 / NS 436 - the "NS" looks a LOT
like one of National Semiconductor's
old logos. Did NatSemi ever make LED display panels?
Yes, and they are rather delicate, they were not hermetically sealed (at least the ones I
have seen).