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- Phil Allison
May 13, 2007, 3:53 am

Hi to all,
I have an 9 volt DC plugpak adaptor purchased, along with and LED display
scientific calculator, back in 1972 or 73.
Makes it nearly 35 years old.
It is in daily use with another device and still works perfectly.
See pic on ABSE.
Anyone got an older unit is good working order ?
....... Phil

Re: Oldest plugpak still in use?
On Mon, 14 May 2007 14:12:17 +1000, Bob Parker

60s.
Despatch
The EM40x series from STC came out around mid to late 60's at the same
time as the 1N400x. Between the OA210 and the EM40x series the smaller
and much more user friendly (compared to the OA210) 1N3254 (DO-26)
came out. This was rated 400v @ 750mA and although it had a metal case
it was insulated with a clear pvc jacket. It made for much quicker and
tidier installation on all those LME relay coil tags :-)

Re: Oldest plugpak still in use?
"Ross Herbert" wrote
The EM40x series from STC came out around mid to late 60's at the same
time as the 1N400x. Between the OA210 and the EM40x series the smaller
and much more user friendly (compared to the OA210) 1N3254 (DO-26)
came out. This was rated 400v @ 750mA and although it had a metal case
it was insulated with a clear pvc jacket.
****What was the Ducon epoxy cased blue power diode?400 V,500mA,1N1763
springs to mind! Available in 1964.
Brian G

Re: Oldest plugpak still in use?
On Mon, 14 May 2007 05:29:16 GMT, "Brian g"

same
smaller
case
V,500mA,1N1763
1N1763 was similar to the OA210 in physical shape and characteristics.
Another type used in place of the OA210/1N1763 was the Texas
Instruments 1S103 (circa 1962 - I have some still). It was in a
similar top-hat style to these two but it was rated at 400V, 750mA
(same as 1N3254) and was also available in a clear shrink pvc jacket
like the 1N3254.

Re: Oldest plugpak still in use?

**I dunno what mine was. It had a yellow plastic thing in the centre. I also
purchased it from Radio Dustpatch. I bought it when I was 14 years old (ca.
1967) for the family's portable (solid state) TV set. The old man took it to
the local TV guy for service and was horrified when they quoted him $150.00
to fix it. He asked if I'd have a go. Fortunately, in those days, there was
a schematic with the set. It worked OK on 12 Volts, but not on 240VAC. I
reasoned that it was either the tranny or the bridge. I used my meter
(Sanwa) that the old man gave me for Christmas to test the tranny. All
looked OK, so I hopped a train to Central and bought a few diodes, soldered
them in and the thing has worked ever since. The old man was pretty chuffed
and figured the multimeter was a bloody good investment.
--
Trevor Wilson
www.rageaudio.com.au
Trevor Wilson
www.rageaudio.com.au
--

Re: Oldest plugpak still in use?

I doubt that there would have been many low power/low voltage consumer
devices around prior to the 60's, so therefore not much of a market
for a plugpack. The few that were would use batteries, and/or have an
internal transformer.
Quite possible too that the transformers then were less efficient and
therefore had to be much heavier, larger and run hotter to supply the
same VA as a modern ironcore unit, which would limit the possible VA
rating that you could fit inside a plugpack without making it too
large or heavy to be of practical use.
Things suddenly got smaller, lighter and more portable and there was
no room left for a transformer inside, and the plugpack soon arrived.
As in Phil's example, it would be hard to fit a transformer inside a
pocket calculator, and even if you could, the calculator would
probably be pulled off the table by the weight of even the lightest
legally allowable mains cord ;)
The first plugpack I ever saw was about 1974, for some reason my
parents bought a "sheen" LED display calculator 9v battery powered but
it also came with a plugpack, I cant remember seeing any before that.
Soon after that, they started appearing everywhere, and most battery
operated devices would at least have a "DC IN" socket to accept a
plugpack.
The oldest I have would be from late 1970's, would be a tandy 9v unit,
though I havent used it in many years. I would be confident that it
still works perfectly though.

Re: Oldest plugpak still in use?
"kreed"

** What nonsense.

** A 9 volt radio "battery eliminator" only needs to have 2 watts output -
so a tiny filament transformer does the job.
They were around in the early 1960s, but not in the form of a plug pack. I
recall seeing such eliminators on sale, in white plastic boxes with two wire
AC leads and a 9 volt snap for output.
Made by Ferguson Transformers and others.
Not double insulated, as that come along later.
....... Phil

Re: Oldest plugpak still in use?

**Not me. I bought one of those calcs. $104.00 as I recall. The damned
calculator fell apart, but the charger is probably still OK. As I recall, it
also has a 3.5mm jack plug on the end? Dumb. And cheap. Still and all, it
was a much cheaper calculator than the HP. I'll bet the HPs didn't fall
apart though.
--
Trevor Wilson
www.rageaudio.com.au
Trevor Wilson
www.rageaudio.com.au
--

Re: Oldest plugpak still in use?
"Trevor Wilson"

** Nothing just "falls apart" - fools damage them.
TW is full of shit as usual.
My EMONA LED scientific calc was faultless for 8 or 9 years, only dying
when the internal Ni-Cds leaked.
I got a TI LCD scientific calc - total lemon, the keypad was a diaster.
Finally got onto Casio - no complaints with them.
....... Phil
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