[Coco] A hint for NitrOS-9, MPI, and "hard drive" PAK

[Gene Heskett]

On Thursday 19 December 2013 16:33:28 Luis Antoniosi (CoCoDemus) did opine:

> It takes a month to arrive. It's normal.
> 
> On Thu, Dec 19, 2013 at 4:18 PM, Gene Heskett <gheskett at wdtv.com> wrote:
> > On Thursday 19 December 2013 16:18:08 Luis Antoniosi (CoCoDemus) did 
opine:
> >> On Thu, Dec 19, 2013 at 11:38 AM, Gene Heskett <gheskett at wdtv.com> 
wrote:
> >> > SC77527
> >> 
> >> UTSource does have it:
> >> 
> >> http://www.ebay.com/itm/SC77527P-Manu-MOTOROLA-Encapsulation-DIP-16-/
> >> 120 920875961?pt=LH_DefaultDomain_0&hash=item1c277223b9
> >> 
> >> I bought 2 from them and it works. I have one spare here.
> > 
> > He just sold 2 more, thanks Luis.

I am also wondering if anyone has ever had the full specs on that chip, I 
have no clue if it is actually even rated for the full plus-minus 12 volts 
on its RS232 output buffers.  The schematic rather conveniently leaves out 
those magic smoke alarm insurance details.  The old green coco manual may 
cover that in better detail.

Obviously at its age, theres no chance its CMOS at all, probably NMOS & 
making some heat normally. OTOH, its voltage regulator section was running 
at flea power as there was no pass transistor left for it to drive on that 
board.  So that end of the die was running cooler than "normal".

Unlike NMOS, Std 4000 family CMOS stuff can take a very large supply 
overvoltage.  I once used a 4028 to decode border times in a character 
generator, with a total applied voltage of 28 volts on what was supposed to 
be a 15 volt chip.  But with 28 volts, it was about 4x faster than the pdf 
said, and which I needed for clean borders, and might have warmed up about 
250 milliwatts worth, and ran that way for several years at KRCR in Redding 
CA. Old NTSC days in the 79-82 time frame.

If anyone has that data, I'd sure appreciate it.

Cheers, Gene
-- 
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* joeyh wonders why everyone wants to know how tall he is
<james> joeyh: it helps the sniper
A pen in the hand of this president is far more
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