core matt repair

jim stephens jwsmail at
Tue Jul 20 23:50:24 CDT 2021

On 7/20/2021 10:13 AM, pspan via cctech wrote:
> I worked at a company called DMA located in Amery Wisconsin during the 
> 80's and 90's that did do core mat repair. Yes, the gal that did the 
> work used a scope. She replaced cores and wires. Good luck finding 
> someone to do that work now. If I remember the process, first the mat 
> was removed from the driver assembly, then the varnish was removed. 
> Then the mat was repaired and revarnished and then reassembled and 
> final test before returned to the customer. 
There was a company started around a lady who did the core repair (one 
of two) at Microdata. They had inhouse built up from scratch cores of 8 
and 16k size.  Later the Ampex core division which was sold to CDC 
manufactured a 32k version.  There were also Keronix 8k which went in 
Micro 800s and 1600s.  Earlier there were 4k boards for the 800s.

Anyway the company was Memtek and was located on Grand Ave in Santa Ana, 
CA.  They ran into the early 80s until the married couple won one of the 
early lotteries for $1m.  The lady wanted to keep working and the 
operated for another 18 months when they hit another jackpot for $1m. 
That was all she wrote.  I had a chance to buy the core rework 
equipment, but didn't.

There was a pretty expensive micro spot welder that she used with a 
microscope and a lot of skill plus some cutting devices to free the 
wiring.  The patches she did (and the others I saw from the Microdata 
lady that remained there) looked like they stood up in the air over the 
core plane.  used an acetone soluble material to hold the patch with a 
tiny dab on the patch.

The Microdata operation that manufactured 16k cores was relocated to 
Puerto Rico and ran for a number of years.

The welding device as I understood it was pretty expensive and very 
precise.  I saw, but didn't photograph both off the rework stations.

Somewhere in the pile because we (Microdata) manufactured core I have a 
big box of sample vials dumped by a purchasing engineering guy when he 
was laid off.  I think they were still buying cores, but he wasn't in a 
good mood that day.

A lot of good stuff went home with me that evening as I wasn't laid of.

As one of my early exercises like that felt like a vulture, but it was 
funny as I found three other guys picking thru cubicles of laid off guys 
picking over goodies.  Felt pretty bad, but you gotta pick up stuff when 
it presents itself.

Observation about that, was on a Friday the layoffs took place.  The 
hatchet man thought that he actually had a job in charge or Engineering, 
he was fired the second Friday after he terminated about 40 engineers. 

And the slow ones that thought about the empty cubicles. took to about 
Tuesday for some of them to mention in casual conversation (Gee maybe 
some good stuff is left in the laid off guy's cubes / offices).  Well, Duh.

anyway a story about core and other stuff.


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