12 Dec
2003
12 Dec
'03
11:39 a.m.
Hi,
Someone's just given me a Commodore Minuteman 3MW (model MM3MW) calculator.
The device itself is working fine, but I still need to replace the battery
pack and charge connector (the batteries were rechargeable nicad, N size).
Anyway, just to satisfy my curiosity, I'd like to get some data on the ICs
used inside it - these are:
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.
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).
NSA298 / NS 436 - the "NS" looks a LOT like one of National
Semiconductor's
old logos. Did NatSemi ever make LED display panels?
Now, to finish satisfying my curiosity, does anyone know anything about the
Commodore MM3MW? A schematic diagram or service manual would be nice :)
Thanks.
--
Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem(a)dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI
12 Dec
12 Dec
12:17 p.m.
On Fri, Dec 12, 2003 at 10:39:31PM +0000, Philip Pemberton wrote:
Hi,
Someone's just given me a Commodore Minuteman 3MW (model MM3MW) calculator.
I'd be interested in any info as well. I have a genuine C= wall wart to go
with mine, bought *years* later, in a box of assorted cables/mice/etc from
a nearby thrift store.
Mine seems to be having problems with dirty switch contacts. It's too
erratic to use. I have not attempted to fiddle with the keyboard directly.
-ethan
--
Ethan Dicks, A-130-S Current South Pole Weather at 12-Dec-2003 23:10 Z
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Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html
12:35 p.m.
In message <20031212231758.GD8803(a)bos7.spole.gov>
Ethan Dicks <dickset(a)amanda.spole.gov> wrote:
On Fri, Dec 12, 2003 at 10:39:31PM +0000, Philip
Pemberton wrote:
Mine came with the power brick (it's more of a
cube-on-a-wire), but I don't
know if it came with the calculator. I assume it did - the calculator would
be pretty useless without it.
Hi,
Someone's just given me a Commodore Minuteman 3MW (model MM3MW) calculator.
I'd be interested in any info as well. I have a genuine C= wall wart to go
with mine, bought *years* later, in a box of assorted cables/mice/etc from
a nearby thrift store. Mine seems to be having problems with dirty switch
contacts. It's too
erratic to use. I have not attempted to fiddle with the keyboard directly.
This
one's been sitting in a cupboard for roughly twenty years and it still
works flawlessly. Unfortunately, being the clumsy idiot I am, I went and put
a scratch in the back casing while I was trying to remove the corroded power
connector. Even after a liberal dose of WD40 the locking nut refused to
budge. In the end I grabbed the connector with a pair of heavy-duty
sidecutters, snapped the plastic casing and destroyed the thread on the screw
fitting. Needless to say, the locknut fell off rather quickly after that
treatment - it had corroded onto the screwthread. Bah.
Anyone know if there's a way to repair scratches in plastic? :)
On a lighter note, I've managed to fix my dead Acorn A4 with the aid of a
pair of 0.33 Ohm 0.6W flameproof resistors. There are two of them fitted
between the 6-pin power connector and the IDE connector. After a half-hour
desolder-and-replace session, the machine came back to life. Now I need to
fix the wretched display data flat-cable - it's got a crack in it :-/
Later.
--
Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem(a)dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI
(A)bort (R)etry (W)ire up to a Tesla Coil and watch it glow like a lightning bug.
12:37 p.m.
ITT / 492-5 / 7445 - these appear to be LED drivers.
I've never seen a part
How about a 75492? I think that's an LED driver? The 7445 part sounds
like a date code...
number like this. BTW, the "7445" is
printed vertically, the rest of the
p/n is printed horizontally (as normal).
NSA298 / NS 436 - the "NS" looks a LOT like one of National
Semiconductor's
old logos. Did NatSemi ever make LED display panels?
Very much so! IIRC the display in the Science of Cambridge MK14 was an
NatSemi part (and was originally a calculator display). I've certainly
seen a NatSemi LED (and display) databook, I may have one somewhere.
-tony
10:26 p.m.
In message <m1AUwqq-000J2vC@p850ug1>
ard(a)p850ug1.demon.co.uk (Tony Duell) wrote:
According to Chipdir, the 75492 is a hex Darlington driver. I guess that's
about right for a calculator with an LED display.
"Everything you ever wanted to know about National Semiconductor's deep dark
past... as an LED manufacturer" :)
I like the HP HDSP-2202s though - cute, even if you have to do the scanning
manually.
Later.
--
Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem(a)dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI
Drive not ready: (A)bort, (R)etry, (F)ix with a hammer?
ITT / 492-5
/ 7445 - these appear to be LED drivers. I've never seen a part
How about a 75492? I think that's an LED driver? The 7445 part sounds
like a date code... old
logos. Did NatSemi ever make LED display panels?
Very much so! IIRC the display in the Science of Cambridge MK14 was an
NatSemi part (and was originally a calculator display). I've certainly
seen a NatSemi LED (and display) databook, I may have one somewhere. 
3:55 p.m.
On Fri, 12 Dec 2003, 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.
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).
The 74xx numbers are most likely date codes.
--
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13 Dec
13 Dec
2:53 a.m.
In message <Pine.LNX.4.33.0312121854520.9998-100000(a)siconic.com>
Vintage Computer Festival <vcf(a)siconic.com> wrote:
The 74xx numbers are most likely date codes.
And
would seem to tally with the general age of the calculator - i.e. the
back end of 1974.
Anyway, I couldn't get N-sized Nicad batteries, so I bought four 650mAh 2/3AA
NiMH cells. I've got the calculator on charge now - fingers crossed...
Later.
--
Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem(a)dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI
He's DEAD, Jim. You get the Tricorder, I'll get his wallet!
9:48 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).
11:06 a.m.
In message <3FDB7B29.7E63C55C(a)cs.ubc.ca>
Brent Hilpert <hilpert(a)cs.ubc.ca> wrote:
Eep.
Anyway, being the nutter I am, I intend to design and build a fairly simple
programmer's calculator. Why? Because I've got a load of microcontrollers in
my junkbox. Oh, and the pack of Hewlett-Packard HDSP-2202s. :-/
Later.
--
Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem(a)dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI
"I'll take your 20kV and raise you 200kV. Go on, step off that plate. I dare
you."
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.
This would be the same WesternDigital that made
the 1770 series of floppy
drive controllers then. Neat - I didn't know they made calculator chipsets as
well.
I own a piece of history *grin* :)
If those drivers are 75492 as Tony suggests, you can
see an example of
their use at
I've got a copy of the TI SN75492 datasheet somewhere. %DEITY
knows if TI
still make them, though.
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).
7533
days inactive
7534
days old
8 comments
5 participants
participants (5)
-
ard＠p850ug1.demon.co.uk -
dickset＠amanda.spole.gov -
hilpert＠cs.ubc.ca -
philpem＠dsl.pipex.com -
vcf＠siconic.com