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> From: Andrew Werby <drewid@...>
>Subject: Re: My CNC Mill retrofit project
>
>Message: 5
> Date: Mon, 11 Oct 1999 09:21:23 -0500
> From: Ray Henry <rehenry@...>
>Subject: Re: My CNC Mill retrofit project
>
>
>Andrew
>
>It's alive! It's alive! Don't snip ANY wires!
>
>Forgive my impertinence. I've nursed a lot of old machines and I'm fond of
>studying their innerds and the long-term effects of the design decisions of
>their makers. It never occurred to me to ask if it was alive. If it is,
>why do you want to/need to convert it?
>
>[It's alive, but just barely...]
>
>1. If it is short on program memory there are easier ways to overcome that
>than a brain transplant. That punch tape input shown on rammill2.gif
>should provide a dandy drip feed input. An almost trivial task, if the
>machine could be run from tape.
>
>[Punch tape? You've got to be kidding. I suppose it might be possible to
>run it on mag tape, but that stuff's prone to errors. And the thing is
>really senile- I know that even if I manage to trick it into starting
>properly, as soon as I get something going on it , it will crap out
>absolutely. I'm interested in running programs that are more than a
>megabyte, and I just don't think this old control system will be able to
>execute them reliably.]

I didn't mean to suggest that you would run punch tape rather that you
could use the punch tape input to feed commands to your machine. Many of
these older machines had a switch that would allow them to run directly
from tape -- hence you could slip any 8 bit parallel signal to the control
through the tape in wiring. A while back I prototyped a cable and software
to run g code through the parallel port of a pc to a tape in on an old AB
7300 cnc. The cnc would accept all of the code that it needed and then
pause the parallel port.

<snip>

>4. If it goes belly up once in a while - blank screen, milisecond overlaps,
>non operator or program related crashes - these needle in the haystack
>kinds of failures can often be traced to aging contacts and aging
>capacitors. Some of these may be in the power supplies others in the brain
>others in the drives others in the interface circuits and wiring. The
>specific nature of these kinds of failures should determine how far you
>need to go with the retrofit.
>
>[These are more the sort of problems I've noticed. Lately, it has only
>managed to boot up halfway, and won't accept any commands- if it's alive,
>it's in a coma.]

To bad I don't need a vacation in Oakland.

>When I do this, should I send you the old control computer? ]

My wife complains that I've already started a metalworking museum. (but I'd
like to know who made the control. Any tags on it.

Ray