[Coco] sc77527p, AKA SALT chip

[Gene Heskett]

On Sunday 12 January 2014 21:32:54 Luis Antoniosi (CoCoDemus) did opine:

> Page 39 of coco2 service manual. There is one i uploaded to
> colorcomputerarchive.com

That is the same thing I have, and like my copy, does not show how the +5 
volts it regulates is connected inside the chip.  And that is the info I 
need to make a semi-intelligent attempt to change how I power its innards.

What I am tempted to do is, since it all runs on the + & - 5 volt internal, 
is to disconnect the 5 volt feed with a 10 ohm resistor in series with it 
from pin 3 and reconnect my present +5 to the emitter of where the pass 
transistor was, and disconnect the +12 volts from pin 16.  That should get 
the 5 volts into the chip on 1, 2, or 3.  Leave the -12 connected to pin 
15, or run it thru an LM7908 to reduce it to real coco voltage.  And I'm 
still stirring around in my midden heap looking for a small heat sink.  I 
am convinced I have 2, suitable for a 14-16 pin dip, in a yellow shack 
pegboard blister pack, someplace.  But the heap has gotten pretty deep in 
20+ years. And little  always filters to the bottom of a 2 foot deep box.  
Murphy's Law corollary & all that rot. :(

Thanks for the url though.
 
> On 2014-01-12 8:12 PM, "Gene Heskett" <gheskett at wdtv.com> wrote:
> > Hi all;
> > 
> > I had a request near the bottom of a message I posted yesterday,
> > asking if anyone had an internal drawing on this SALT chip showing
> > how it distributes the internal 5 volts, and where (pin #) it
> > connects to the outside world.
> > 
> > Does such a drawing even exist?  I sure need a copy if anyone has one
> > with more details than what is in the coco manuals.
> > 
> > Cheers, Gene
> > --
> > 
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > 
> > -Ed Howdershelt (Author)
> > Genes Web page <http://geneslinuxbox.net:6309/gene>
> > 
> > * BenC wonders why he has upgraded to 3.3.5-1 before teh X maintainer
> > A pen in the hand of this president is far more
> > dangerous than 200 million guns in the hands of
> > 
> >          law-abiding citizens.
> > 
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > http://five.pairlist.net/mailman/listinfo/coco
> 
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

Prediction is very difficult, especially of the future.
		-- Niels Bohr
A pen in the hand of this president is far more
dangerous than 200 million guns in the hands of
         law-abiding citizens.