1 Feb
2015
1 Feb
'15
11:23 p.m.
A friend of mine gave me a Friden EC-130. It's in pretty good shape, though
it's missing quite a number of screws, as well as the bottom plate.
Pictures here: http://imgur.com/a/OjxCn
As you can see from the pictures, I don't get any distinguishable digits on
the CRT. Thankfully, most of the logic does seem to be working; entering
too many digits before the decimal place as set by the rotary switch
results in an overflow upon hitting enter. Entering thirteen 9s and
dividing by 1 takes about 2 seconds (the button stays depressed; quite
cool), whereas simple adding and subtracting returns the result right away.
Keyboard feels good, and you can see the CRT modulate differently depending
on what's to be displayed.
I've tried the obvious thing of reseating boards and rotating the pots back
and forth a bit, to no avail.
My understanding is that schematics are not available for the unit. Is that
still correct? It wouldn't be a hard unit to reverse engineer; it's just a
whole lot of components.
If anyone has any advice to offer, it would be much appreciated.
Thanks,
Kyle
2 Feb
2 Feb
12:03 a.m.
Hi Kyle,
While I certainly cannot claim any level of expertise in the matter, I do
happen to have a functional EC-130 here. Or I should say, it was functional
the last time I examined it, which was around one year ago. My machine was,
likely still is, suffering from one malady that yours is not - my keys will
not hold-down during long computations. As you might be aware, the keypad
lock-out feature was implemented due to the fact that a talented keypunch
operator could frequently get 'ahead' of the machine - which would result
in errant output.
Likewise, I have no service documentation for it. But if I can be of any
assistance, so far as providing voltage / resistance / component readings,
I'll try to do my best as time allows.
They are fascinating machines - all the more amazing, considering that they
were almost entirely designed by a single engineer.. save the analog /
display portions, as I understand it.
On Sun, Feb 1, 2015 at 10:23 PM, Kyle Owen <kylevowen at gmail.com> wrote:
A friend of mine gave me a Friden EC-130. It's in
pretty good shape, though
it's missing quite a number of screws, as well as the bottom plate.
Pictures here: http://imgur.com/a/OjxCn
As you can see from the pictures, I don't get any distinguishable digits on
the CRT. Thankfully, most of the logic does seem to be working; entering
too many digits before the decimal place as set by the rotary switch
results in an overflow upon hitting enter. Entering thirteen 9s and
dividing by 1 takes about 2 seconds (the button stays depressed; quite
cool), whereas simple adding and subtracting returns the result right away.
Keyboard feels good, and you can see the CRT modulate differently depending
on what's to be displayed.
I've tried the obvious thing of reseating boards and rotating the pots back
and forth a bit, to no avail.
My understanding is that schematics are not available for the unit. Is that
still correct? It wouldn't be a hard unit to reverse engineer; it's just a
whole lot of components.
If anyone has any advice to offer, it would be much appreciated.
Thanks,
Kyle
2:44 a.m.
On 2/1/2015 9:03 PM, drlegendre . wrote:
Hi Kyle,
While I certainly cannot claim any level of expertise in the matter, I do
happen to have a functional EC-130 here. Or I should say, it was functional
the last time I examined it, which was around one year ago. My machine was,
likely still is, suffering from one malady that yours is not - my keys will
not hold-down during long computations. As you might be aware, the keypad
lock-out feature was implemented due to the fact that a talented keypunch
operator could frequently get 'ahead' of the machine - which would result
in errant output.
Likewise, I have no service documentation for it. But if I can be of any
assistance, so far as providing voltage / resistance / component readings,
I'll try to do my best as time allows.
They are fascinating machines - all the more amazing, considering that they
were almost entirely designed by a single engineer.. save the analog /
display portions, as I understand it.
This block diagram may help at least the
discussion.
http://www.oldcalculatormuseum.com/f130block-l.html
I'd try to trace back if there is any possibility of doing so, on the
display matrix, or maybe the blanking. Your display looks like the
deflection is pretty much well adjusted, but the display matrix logic
isn't working to scoot the beam around when it counted to the position
of a digit.
Maybe try scoping with care to see how the input to the CRT on the
display drive works.
Hams broke up a huge number of these calculators in the past to harvest
just the CRT and junked the rest. I got my three from a guy who had
been a singer / friden service guy, and beat out a number of hams
answering a classified ad for his sale. The CRT may be a well known
commodity if you can find it, or know some older hams who might know who
to ask. ISTR there was a sheet on how to hook them up.
(OT) Sorry, Al, he had a lot of documentation, but I was not in collect
everything mode then. It was all for the take free., and he had a test
machine in his living room (Singer system with a 10 platter drive.)
Rare to unknown now days.
Nice find.
Jim
On Sun, Feb 1, 2015 at 10:23 PM, Kyle Owen
<kylevowen at gmail.com> wrote:
A friend of mine gave me a Friden EC-130.
It's in pretty good shape, though
it's missing quite a number of screws, as well as the bottom plate.
Pictures here: http://imgur.com/a/OjxCn
As you can see from the pictures, I don't get any distinguishable digits on
the CRT. Thankfully, most of the logic does seem to be working; entering
too many digits before the decimal place as set by the rotary switch
results in an overflow upon hitting enter. Entering thirteen 9s and
dividing by 1 takes about 2 seconds (the button stays depressed; quite
cool), whereas simple adding and subtracting returns the result right away.
Keyboard feels good, and you can see the CRT modulate differently depending
on what's to be displayed.
I've tried the obvious thing of reseating boards and rotating the pots back
and forth a bit, to no avail.
My understanding is that schematics are not available for the unit. Is that
still correct? It wouldn't be a hard unit to reverse engineer; it's just a
whole lot of components.
If anyone has any advice to offer, it would be much appreciated.
Thanks,
Kyle
5:05 a.m.
On 2/2/2015 12:38 AM, drlegendre . wrote:
Forgive me, or don't..
On Mon, Feb 2, 2015 at 1:44 AM, jwsmobile <jws at jwsss.com> wrote:
My buy was not unusual. The dealer had sold out probably 50 of them and
I got the last ones he had. They were considered more valuable for the
display than as an artifact. Remember this is in the 1975 and prior
time frame. And a lot were kept around, but there were really a lot
retired as the revolution of the small solid state units showed up.
The Wang and fancier older units with scientific processing (read
floating point) survived quite a bit longer. And the HP ones of course
were in a different class.
But going from 71 when I started college and into the time when I found
these, the small LED 7 segment gizmos were mostly wiping these out. I'm
not talking everywhere, but these would be in business settings, and the
newer calculators were more popular than these which are effectively
RPN. Not that you couldn't do what you needed to, but in business,
calculators that ran tapes didn't easily map functionality into this
unit, so shifting to one of these and then back to a possible mechanical
calculator to run a tape not only required a change in how you ran the
info, but also how you did the problem.
I never would have considered breaking one up unless it was a basket
case, as the last thing that burned out in these were the CRT modules.
But he had sold a lot of junkers he had to a local ham who was going to
salvage them. He had been given notice that he would not have a job,
and he had a house full of crap to clear out as far as he was
concerned. As I do now, I showed up and transfer crap from one place in
Lafayette, La, to my place.
I don't call them assholes, but it is unfortunate that more were not
salvaged. But I see why. BTW more perspective on the guy I found it
was not a really good time for him, he could have walked away from the
rented house and left all the crap. Crappy pay from a flaky company was
where he was at and soon no pay.
Jim
Hams broke up a huge number of these calculators in the past to harvest
just the CRT and junked the rest.
Wow, and what a bunch of short-sighted a$$holes they were.
8:39 a.m.
On Sun, Feb 1, 2015 at 11:03 PM, drlegendre . <drlegendre at gmail.com> wrote:
Likewise, I have no service documentation for it. But if I can be of any
assistance, so far as providing voltage / resistance / component readings,
I'll try to do my best as time allows.
Thank you! That will likely be very helpful. I am first going to check the
ripple on the capacitors, as I noticed some waviness in the display.
Perhaps one or more of the electrolytics isn't filtering as well as it did
50 years ago. I did bring it up over the course of several minutes on a
variac; I didn't notice any unusually high currents, and both fuses
remained unbroken. I'd say it's promising!
They are fascinating machines - all the more amazing,
considering that they
were almost entirely designed by a single engineer.. save the analog /
display portions, as I understand it.
Yes, it's quite amazing that with fewer than 200 transistors, as well as a
multitude of diodes, resistors and capacitors (and a delay line, of course)
that a 4-stack 4-function RPN calculator could be made.
Kyle
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