[Coco] Weird CoCo3 problem - AAAARRRGGGGGHHHHH!!!!

[Arthur Flexser]

...except that he'd be getting ?SN (syntax) error if no disk ROM was
detected, not ?IO error.

Art
On Sun, Jan 3, 2010 at 9:17 PM, John Donaldson <johnadonaldson at sbcglobal.net
> wrote:

> Brian,
>   I think I see one big problem right now. You said
>
> Turn her on and was greeted with the 'Extended Color Basic....yada,
>
> If you had the controller installed you should have gotten "DISK EXTENDED
> BASIC" or something like that that tells you that the DSIK ROM has been read
> and is operating. This may explain why all the DISK commands give I/O error
> since the DOS is not present. Look at what is displayed when you put the
> controller in another good system, then look at the display when the
> controller is in the system that does not work.
>
> Either something like this is going on or I am mi-reading your posts.
>
> John Donaldson
>
>
>
> Brian Blake wrote:
>
>> The latest;
>>
>> Upon further testing, R22 was not doing anything. The solder pad on the
>> bottom of the mobo was broke, an the leg on the end that's supposed to
>> connect to C65 had been lifted. I took R22 completely out and replaced it
>> with a new 120-ohm resistor. Then I took a short piece (3/16 - 1/4") of
>> speaker wire and soldered it to the leg of R22 that is supposed to go to pin
>> 4 of the GIME, scraped away some green stuff and soldered the other end
>> directly to the trace. Continuity restored. Continuity from R23 was fine.
>> Cleaned up the solder pads from where I clipped out the 6809, soldered in
>> the socket, installed the 6309 and put everything back together. Turn her on
>> and was greeted with the 'Extended Color Basic....yada, yada' greeting, okay
>> that worked. Tried Tetris, S/S Pak and O-90, all worked as expected. Still
>> have the same problem with the FD-502; POKE &HFF40,1 does not turn on the
>> drive light, and any disk commands end up with an I/O? error with no
>> activity
>>  being present on the drives when the commands are issued...
>> AAAARRRGGGGGHHHHH!!!!
>>
>> I went to R/S today only to find out they no longer carry a logic probe,
>> so I'm stuck with using my DMM for now. When issuing a POKE &HFF40,1 in a
>> loop, IC9 pin 6 is 'HI' on the DMM in logic mode, but, in frequency mode it
>> shows up as a 192.5-kHz signal. Pin 36 of the 40 pin connector shows the
>> same results. Other than evidently ruining a perfectly good 6809, so far the
>> only thing I've accomplished is completing a 6309 swap on a CoCo3 with
>> 'floppy phobia'... So, I'm still open for suggestions. Tomorrow I'll be
>> bringing home my 50-MHz scope so I'll at least be able to look at waveforms.
>> At this point,based on my limited knowledge and materials I'm looking at,
>> I'm leaning towards replacing IC9 to see if that helps, but, I'd rather not
>> start chip swapping just for the heck of it, so PLEASE, if you guys who are
>> far more knowledgeable than I have any suggestions, I'm listening!!!
>>
>>
>> Thanks,
>>
>> Brian
>>
>>
>>
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>>
>>
>>
>
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