[Coco] OT: 63B09

[gene heskett]

On Sunday, October 30, 2011 05:17:55 PM Richard E. Crisilip did opine:

> On Saturday, October 29, 2011 01:48:17 PM Louis Ciotti wrote:
> > I can across an NTE6809 processor and thought I would give it a try as
> > a replacement for the 63b09.  It has an identical Pinot so I figured
> > it may work.  I plug it in the socket, and I get nothing at all.  The
> > external clock (4mhz) crystal does not even work, which on the one I
> > am trying to replace does.  Is the IC bad, or is it a compatibility
> > issue.
> > 
> > On Thursday, October 20, 2011, Louis Ciotti <lciotti1 at gmail.com> wrote:
> > > Off topic, but since the CoCo uses 6809s, figured someone on here
> > > might
> > 
> > know about this.
> > 
> > > I have a radio controller from circa late 80s that uses a 63B09 that
> > > I
> > 
> > think may be bad.  What can I use in its place and is there a source?
> > 
> > > The problem I am seeing is RN6(Pins 24-31) has some "noise" on the
> > > line
> > 
> > and the waveform is not exactly square like the rest of the data lines
> > when observed with an oscilloscope.
> > 
> > 
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > http://five.pairlist.net/mailman/listinfo/coco
> 
> If I am wrong, I am sure the more knowledgeable CoCo folks will correct
> me. The CoCo requires a CPU with an external clock as the 6809E and the
> 6903Es are.

This is not in a coco, Richard, its some sort of a ham radio controller I 
believe if you follow the thread back far enough.

The OEM chip is an HD63B09P, CMOS but not an E model.  My guess is that 
when he plugs in the NTE part, which is likely either NMOS or PMOS, the 
biasing of the internal oscillator is so far off compared to what the 
Hitachi CMOS chip needs that the internal oscillator never starts.

One thing that would help me ascertain at least a better SWAG was a comment 
he made about noisy data lines.  Apparently the OP has a scope, so if he 
could post a properly zeroed, dc coupled, 100 mhz or so bandwidth, snap 
shot of the scope screen while looking at 1 or 2 of these noisy signals, 
put on one of the pastebin's & give us the link so I could take a look.  
That might help clear up my cloudy crystal ball quite a bit.

Something else that comes to mind also is aged, oxide blackened IC legs & 
socket contacts.  Temporary fixes can be had by lifting each end of the 
chip about 1/16" and pressing them back down, but the real fix is probably 
to remove them all, keeping track of what type goes in which socket, pour 
out 2/3rds of a cup of _fresh_ "Tarnex" in a small bowl, drop all the chips 
in and stir gently with a long q-tip stick or ?? until the chip legs are 
nice & clean, nearly white.  Pick them back out of the cup and rinse each 
one in warm running water, drop on a bath towel and dry with a hair dryer.  
Reinstall & see if that fixed it.  I have probably used something in excess 
of a 2 gallons of Tarnex for that over the last 25 years.  Sometimes I have 
resorted to wetting the sockets with it using a q-tip, let them soak for 
half an hour, then rinse the whole board with warm running water using the 
spray head in the kitchen sink, but because you can't agitate it down 
inside the socket pins, its not all that effective.  I have had to run down 
the bad socket and replace it occasionally, which is a right PIMA.  But 
when something to replace the recalcitrant device was in those days 
25-50k$, you fixed it by whatever means you could.  When I say rinse, that 
means 20 to 30 minutes of running water, don't even leave the smell of 
tarnex in the room.

Oh oh, my soap box is crumbling. ;-)

> The chip you are trying has an internal clock. Also just
> because the pin match up, you MUST be very careful. The 68020 and 68030
> match pin for pin too, but that does not mean you will not let the blue
> smoke out 8-(.
> 
> --
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> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco


Cheers, Gene
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