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Re: Apple //c++ experiments...

a2aviator@gmail.com wrote:


The same is also possible, in theory, with the sealed Zip Chip unit.
It's not a potted block, it's a ceramic hybrid with bare circuits
under the plastic dome like lid which is just glued down.

DO NOT MESS WITH THIS LID unless YOU KNOW WHAT YOU ARE DOING. This is
not an invitation to mess with your Zip Chip, this is just
informational reference.


Interesting.  My Zip Chips have a potting compound on the bottom,
out of which the wire leads stick.  I never tapped on the top to
determine whether it was full or empty, I just presumed full!

This offers good hope of a cure for folks with a Zip Chip with
a broken "pin".


Thats not to say you're going to just find a tiny little crystal in
there either.


But there is a tiny little crystal in there.


But a Zip Chip is made up of a 65C02, SRAMs, the Patented circuit, and
a crystal. Stamped. Raw. Which is why they had such a high and sudden
failure rate. When they switched to mounting off the shelf SRAMs on
the bottom of the unit, it was a major improvement. The stuff was not
tested and burned in, so the failure rate that the foundry experiences
was directly passed on to the consumer, for the most part. This made
the Zip Chip very expensive cost of goods wise, because like a
manufacture of stamps out 1,000 SRAMs, 200 of them would not yield
passing results and thus, not be sold.


So the first production run(s) were flipped bare dice on the ceramic
substrate?  No wonder they had problems...

I was certainly happy to see the SRAM packages on my later ones.

-michael

NadaNet file server for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

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