trs-80 model II trouble--problem solved..and follow-up

Chuck Guzis cclist at
Fri Dec 18 00:48:54 CST 2009

On 17 Dec 2009 at 21:07, Fred Cisin wrote:

> Let's not do like Gibson/Spinrite.
> Perhaps the manufacturer had some test for the chips that was more
> rigorous than what we have.  If they say that their product is bad,
> I'll believe them, even if it "tests good" most of the time.

Let's put this in its historical context.  When Intel started making 
16K 16-pin DRAM, yields weren't terrific, so they sold a limited 
number of "half-good" parts--2109s early on, probably to mark their 

About 1978-79, the US got in a trade spat with Japan over DRAM 
"dumping" and the supply of DRAM abruptly dried up (pesaging other 
similar periods yet to come).  You couldn't find 16K DRAM for any 
price in quantity.  There was at least one break-in for the sole 
purpose of stealing DRAM  that I'm aware of, nearly putting the firm 
out of business..  (Later, there was a hijacking of a truck carrying 
mostly CPU chips, but that's another story).  The Mercury-News 
archives doubtless has the story somewhere.

So, given the situation, sifting through 8K DRAM to find decent 16K 
parts was quite reasonable.  I recall that our 2109s were tendered 
somewhat apologetically by our Intel sales rep when we asked for 2117 
DRAM engineering samples.

These were the purple ceramic carriers with gold lid version.  
Plastic was later.  When the antidumping order was lifted, we 
received a bunch of NEC uPD416s.  We were surprised at how much 
better they were than the Intel parts (I still have those too).


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