Re: tape-O-matic

Ted Robbins wrote:

> From: Ted Robbins <rtr@...>
>
> That rotogenerator is called a Georator, It is wonderful, isolating surges
> on a typical machine shop line, having enough inertia to get by a couple of
> dropped cycles. Yes, they used it to drive the logic, plus and minus 12
> volts if I remember correctly. However it is really Obsolescent.

A Georator? Isn't that a 'mini-ups' flywheel energy store, that puts out
120 V 60 Hz power? I've seen those in other, critical-use computer
systems, like the one at NASA-Wallops Island that showed the range
safety officer where the rocket would plop down if the engine quit
right now.

> That's
> why I suggested when you brought the subject up, to get rid of the control
> cabinet full of elco connectors, each planning on becoming intermittant
> just when you can't afford it.

Elco Vari-lock connectors? My Allen-Bradley 7320 has large numbers
of those, in various connector housings. The pins are the ones that look like
a 2-pronged fork? Yup, they are trouble! I found that whenever I
opened the cabinet up and disturbed any of the big cables, things started
going flakey, and you had to wiggle stuff until the controls and indicators
started working right. I eventually used a small screwdriver to bend the
two fingers together a little bit, and it was much better, but still a continuous
worry. One time, while right in the middle of cutting a part, about half
the buttons on the console, including some of the stop functions, and
the feed rate override stopped working. Yikes!

> Yes, you can use the circuits. The first thing you do is regap the forks
> on every elco connector and never swap boards without troubleshooting to
> the board you are going to swap. You don't just swap rows of boards unless
> you check the gaps on the elco connectors every time you insert a card. If
> you get rough with the pins you will break them or push the mother board
> pins out of the motherboard.

Yup, that's them, allright. The military square Elco connectors aren't too
bad, but the ones with one or two rows of exposed pins attached to circuit
boards are very easy to over stretch the contacts on.

> Do you really want to go up a learning curve that holds only obsolete
> information? Or would you really be better off going up a current
> leaaarning curve.
>
> Jon is right asgain. The control was developed (Not using the more modern
> spindle drive) in about 1962. Those discrete boards suck up all the
> current the georator puts out. Gas heating for your shop is much more
> practical thean electrric heating with that control. In thae summer, when
> the ambient temp reaches into the mid eighties, the silicon reaches thremal
> runaway. The normal procedure is turn it off or air condition it.

My Allen Bradley 7320 is known in the Industry as unreliable. I think
between the Elco contacts and the design, with no continuously operating
fans and a cabinet cooler that switches on at 145 F, I can see how it got
such a reputation. But, that's not all. On most of the old controls it was
extremely hard to reconfigure in the field. Most of the changes for resolution,
servo gain, acceleration, error tolerance, etc. were hard coded into a
macro deck that guided a mainframe computer through the process of
converting an assembly language program to machine code for the CNC.
(With a control that was designed in 1962, there is likely to be no computer,
so configuration may be by rewiring the control! Gasp!)

Jon