Friden EC-130 Help

drlegendre . drlegendre at
Sun Feb 1 23:03:49 CST 2015

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> 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:
> 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

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