[Coco] Weird CoCo3 problem...

Brian Blake random_rodder at yahoo.com
Fri Jan 1 19:48:17 EST 2010


Nope - no logic probe. What kind of signal should be seen there? My DMM has some logic functions built into it, but, I'm not sure off hand what it's capable of...



________________________________
From: Mike Pepe <lamune at doki-doki.net>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Fri, January 1, 2010 7:39:58 PM
Subject: Re: [Coco] Weird CoCo3 problem...

That's pretty strange. If you have a logic probe you can do some more investigation. The LS138 chip may be faulty.

> -----Original Message-----
> From: coco-bounces at maltedmedia.com [mailto:coco-
> bounces at maltedmedia.com] Ong happens accept an I/O error - not light, no
> disk activity, nothing...
> 
>  Behalf Of Brian Blake
> Sent: Friday, January 01, 2010 3:24 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: Re: [Coco] Weird CoCo3 problem...
> 
> Tried the POKE and no drive activity light came on. Anytime I try to
> access the disk, nothin
> 
> ________________________________
> From: Mike Pepe <lamune at doki-doki.net>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Fri, January 1, 2010 6:08:28 PM
> Subject: Re: [Coco] Weird CoCo3 problem...
> 
> I suspect the 6809 as well. But if you do a poke &HFF40,1 the drive 1
> activity light should go on. If not something else may be wrong.
> 
> > -----Original Message-----
> > From: coco-bounces at maltedmedia.com [mailto:coco-
> > bounces at maltedmedia.com] On Behalf Of Brian Blake
> > Sent: Friday, January 01, 2010 2:36 PM
> > To: CoCoList for Color Computer Enthusiasts
> > Subject: Re: [Coco] Weird CoCo3 problem...
> >
> > Hi Arthur,
> >
> > Unfortunately, it's not socketed. Tho, I have about 9 6309's and
> plenty
> > of sockets... hmmmm.... maybe tomorrow....
> >
> >
> >
> > ________________________________
> > From: Arthur Flexser <flexser at fiu.edu>
> > To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> > Sent: Fri, January 1, 2010 3:56:15 PM
> > Subject: Re: [Coco] Weird CoCo3 problem...
> >
> > I vaguely recall something like this happening to me years ago that
> was
> > fixed by replacing the 6809.  If this machine and one of your others
> > has had
> > the 6809 socketed, it would be easy enough to swap in a 6809 from one
> > of the
> > other machines and see if the problem goes away.
> >
> > Art
> >
> > On 1/1/10, Brian Blake <random_rodder at yahoo.com> wrote:
> > >
> > >
> > >
> > > All of these new developments on the CoCo front finally lit the
> fire
> > under
> > > my arse to set up real hardware again. Besides my repack project, I
> > have 3
> > > other CoCo3's, two with 512k upgrades (one C9 and one PBJ) and one
> > 128k. The
> > > one with the C9 upgrade works fine - can load and play Sockmaster's
> > Donkey
> > > Kong.
> > >
> > > The one with the PBJ upgrade, not so... At boot, it comes up as it
> > should
> > > with the proper display. However, any floppy commands are met with
> no
> > > response from the floppy drive (with an FD-502 controller) at all.
> > Almost
> > > like the drive is off. The drive responds as it should in the other
> > two
> > > machines. Upon removing the top case and k/b, I saw two wires, each
> > had been
> > > soldered to opposite sides of R23. Now, under the keyboard, is
> > another wire
> > > with alligator clips on each end, and the clips are holding on to
> the
> > bare
> > > end of the wires soldered to R23, effectively bypassing the
> resistor.
> > I'm
> > > looking for the PBJ instructions, pretty sure I have them, to find
> > out if
> > > this is called for. I can also see where C65 & C66 have been cut
> and
> > > re-soldered. I have reseated the GIME and the PBJ memory chips, and
> > cleaned
> > > the 40 pin connector.
> > >
> > > Any other suggestions? My 100MHz o'scope bit the dust so I don't
> have
> > that
> > > tool any more (anybody have a CRT for a Leader 3 channel 100MHz
> > scope??)
> > >
> > >
> > > Thanks,
> > >
> > > Brian
> > >
> > >
> > >
> > >
> > >
> > > --
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> > > Coco at maltedmedia.com
> > > http://five.pairlist.net/mailman/listinfo/coco
> > >
> >
> > --
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> >
> >
> >
> >
> >
> > --
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> > http://five.pairlist.net/mailman/listinfo/coco
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> 
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> 
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