[Coco] Weird CoCo3 problem...

Sat Jan 2 02:10:15 EST 2010

15KHz sounds about right for a loop like that. Every poke to that address should drive SCS low momentarily.

Two other things come to mind for checking- if you put this controller/drive on another machine, does the poke make the drive activity light come on? Second thing is- do any other cartridges work on this machine? Any game paks to test with?

> -----Original Message-----
> From: coco-bounces at maltedmedia.com [mailto:coco-
> bounces at maltedmedia.com] On Behalf Of Brian Blake
> Sent: Friday, January 01, 2010 9:08 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: Re: [Coco] Weird CoCo3 problem...
> 
> Hi Mike,
> 
> Here's what I did - not sure if it was correct:
> 
> 10 POKE &HFF40,1
> 20 GOTO 10
> RUN
> 
> I then checked pin 6 of IC9 - which according to my schematic is the
> /SCS line - HI reading on my DMM in logic mode (<1 = LO, >2 = HI, in
> between it shows the voltage).
> I then checked pin 40 on the 6809 - the /HALT line - and got a reading
> of 1.545vdc.
> Not sure if my DMM would react fast enough, I changed to Frequency mode
> and checked pin 6 of IC9 again - got a reading of about 15-kHz.
> I hit the break key and checked pin 6 again, and it was still HI.
> Shut of the CoCo, waited a few seconds and turned it back on, checked
> again and it was still HI.
> Checking pin 36 on the slot yielded similar results, except the
> frequency was very different ~110-kHz.
> 
> 
> 
> ________________________________
> From: Mike Pepe <lamune at doki-doki.net>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Fri, January 1, 2010 9:45:14 PM
> Subject: Re: [Coco] Weird CoCo3 problem...
> 
> I'd put that POKE &HFF40,1 into an endless loop and look to see if the
> SCS line on the cartridge port is stuck high or if it pulsates.
> 
> Radio Shack used to sell a pretty decent logic probe for about $20. Not
> sure if they still do, but it would help diagnose the problem in this
> case.
> 
> The latch at $FF40 should function independently of a blown out 6809
> HALT line which is what usually indicates a CPU replacement.
> 
> > -----Original Message-----
> > From: coco-bounces at maltedmedia.com [mailto:coco-
> > bounces at maltedmedia.com] On Behalf Of Brian Blake
> > Sent: Friday, January 01, 2010 4:48 PM
> > To: CoCoList for Color Computer Enthusiasts
> > Subject: Re: [Coco] Weird CoCo3 problem...
> >
> > 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
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > 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
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > --
> > > > 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
> > >
> > >
> > >
> > >
> > >
> > > --
> > > 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
> >
> >
> >
> >
> >
> > --
> > 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
> 
> 
> 
> 
> 
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco