[Coco] STATUS - Re: Resurrecting a CoCo (26-3001) with a 26-3029 FDC.

Ryan Pritchard coconut at pritchard.ca
Fri Sep 12 22:12:01 EDT 2008


I mean that the cable is on correct, the drive light and motor turn on  
after I press ENTER when entering DSKINI0 to format the diskette.  The  
drive proceeds to spin the disk and move the head for about 35 track  
adjustments then makes a normal type of I am not going to complete my  
job grind noise, and then I get the ?IO ERROR message.

Unfortunately I do not have an already formatted CoCo diskette.  I  
will have to setup an older 386 / 486 / Pentium class board and case  
to see if these drives actually work, but from your interpretation, I  
likely have to do something with the FDC.  I have read about the need  
to replace the 7416 with 7406.

Regards,

Ryan Pritchard
Fun Extends All Basic Life Expectancies



On 12-Sep-08, at 4:50 PM, Arthur Flexser wrote:

> When you say you get IO errors "at the end" of the formatting  
> routine, I suspect
> you are actually getting them in the middle of the routine, when  
> DSKINI has
> finished writing the tracks (or trying to do so, at least) and first  
> attempts to
> read back from the disk to make sure everything went okay.  So, that  
> raises the
> question of whether your drives are able to read (or write) anything  
> at all.
> Have you checked to see whether an already-formatted disk can be  
> read?  Does the
> drive light come on when a drive is accessed?  It sounds like you  
> might have a
> hardware problem with your disk controller, if both drives are  
> equally affected.
> (If the drive lights are on all the time, you may heave a sigh of  
> relief, for
> that would mean simply that you've plugged the drive cable in upside  
> down.)
>
> Art
>
> On Fri, 12 Sep 2008, Ryan Pritchard wrote:
>
>> Hi all,
>>
>> Thanks to everyone who had responded the to my original post.  Here  
>> is
>> a status update, and from the status I am hoping for some further
>> assistance.
>>
>> Thanks go out to Darren A for setting me up with a Extended Color
>> Basic 1.1 ROM.
>>
>> My 26-3029 FDC is the 7 chip WD1773 based version thus I will not be
>> able to mod it to work at HD.  Oh Well!
>>
>> I have been trying to format disks in either 3.5" or 5.25" (I can't
>> believe I had two boxes of KAO 5.25" DSDD never opened kicking
>> around).  Anyway I get IO errors at the end of the formatting routine
>> regardless of 3.5" or 5.25" drive / media.
>> Here is a list of my 5.25" FDDs:
>> Panasonic JU-475-4 A55
>> Panasonic JU-455-5 AAG
>> Teac FD-55GFR-570-U
>> Teac FD-55GFR 149-U5
>> Mitsumi F509V3
>>
>> 3.5" FDDs
>> Fujitsu M2537D15D
>> Fujitsu M2537B11D
>> Teac FD-235HF 3240-U5
>>
>> For all the drives I have tried to ensure that the DC/RY jumpers are
>> set to Drive Ready and not Drive Change.  I have jumper settings for
>> some of them, but it seems to not help. The cable I am using has been
>> returned to straight through mode.
>>
>> I am still looking for confirmed 64K ram upgrade instructions for the
>> 26-3001 REV E board.  Currently it has 16K installed, the jumpers all
>> mention the 32K setting.  The closest instructions I have found are
>> from an archive of Paul Demarni's Coco pages (http://www.geocities.com/theother_bob/coco_page.html
>> ).  It instructs about the 32K upgrade and makes reference to him
>> having instructions for the 64K upgrade.
>>
>> The other resource I have read about is from the October 1983 issue  
>> of
>> Color Computer Magazine, I really hope someone has that issue, that I
>> can acquire a scan of the article or arrange to acquire the issue.
>>
>> Regards,
>>
>> Ryan Pritchard
>> Fun Extends All Basic Life Expectancies
>>
>>
>>
>> On 24-Aug-08, at 9:53 PM, Ryan Pritchard wrote:
>>
>>> Hello out there,
>>>
>>> Newby to CoCoList and to running a CoCo, but not OS-9 which I am
>>> looking forward to running the NitrOS-9 flavour.
>>>
>>> Fourth attempt to post but this time it should work thanks to Dennis
>>> telling me some information about the mailing list server.
>>>
>>>
>>> I have recently got the bug to play with a CoCo I had acquired years
>>> ago.  The good news for me, is the 26-3001 model I have is the
>>> Revision E mother board which has all the jumpers on it to go all
>>> the way up to 32K (and likely 64K since I know the 64K x 1 chips I
>>> have are all good as they are coming from an Apple 80 Column card.
>>>
>>> Currently the CoCo has 16K in it, and boots up to Color Basic 1.1.
>>> It has an empty ROM socket where if I have understood correctly I
>>> could install and Extended Basic ROM if I had one.
>>>
>>> I am having a problem getting the Disk Basic on the 26-3029 FDC to
>>> boot, and thus cannot format or other wise do anything disk
>>> related.  Is there any common issues with the FDC that I should look
>>> at to determine why the CoCo is not detecting the cartridge and
>>> booting from the FDC ROM?  The PCB for the FDC has the markings LEIA
>>> MV-1 38 84, and has the WD-1773-PH controller chip.  The markings on
>>> the ROM are TMS4764-30NL, B8428L, ZA64342, 804-5364A.
>>>
>>> It does not appear visually to have any burnt caps, resistors, or
>>> chips, though I have not tested any of them.  Also I have tried the
>>> time tested eraser on the contacts to see if that would resolve the
>>> problem, though I have not fully inspected the slot on the CoCo.
>>>
>>> Like many people before me, playing with a CoCo for the first time
>>> in their lives, help would sure be appreciated.
>>>
>>> Regards,
>>>
>>> Ryan Pritchard
>>> Fun Extends All Basic Life Expectancies
>>
>>
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