[Coco] Issues with 26-3022 interface

[Daniel Campos]

Hi Gene,

Em 12/02/2013 02:19, Gene Heskett escreveu:
> On Monday 11 February 2013 22:40:50 Daniel Campos did opine:
>
>> Hello,
>>
>>
> What jumper is set for that drives address?  Where you have it, on that
> "PC" cable, it should be set with ds1 jumpered, and you should have had to
> type DSKINI1.

Since the beginning, I used a PC cable but have removed the twist of the 
cable. It's a straight thru cable now.

> The end of that cable is twisted, so that the drive plugged into the end of
> the cable is also set as drive 1.  But the cable twist makes it drive 0.
>
> For coco drives, I generally reset the address jumpers so the drives are
> addressed in sequence, starting with drive0=ds0 jumpered, and replace the
> cable with a straight thru cable, replacing any plugs on the cable that
> have missing teeth in the sockets.
>
> So your use of DSKINI0, means that drive is properly jumpered I believe.

Yes. That was the first drive from the TRS-80 so it was already jumpered 
to DS0.

>
> The next thing is that there needs to be terminations, in the last drive on
> the end of the cable /only/, and you will have all sorts of I/O errors if
> there are none.  They /must/ be on the end of the cable too else the cables
> signals will have edge ringing from the unterminated stub I see sticking
> out.  So if that drive has 1 or more empty minidip sockets adjacent to the
> edge connector, you are missing those terminations.  The best source for
> those is probably another old drive.

Yes, there is a DIP socket but I don't know his function. Both drives on 
the TRS-80 don't have any terminations on this sockets. Bellow goes a 
picture.

http://img248.imageshack.us/img248/5832/img1265u.jpg


> Specifically, what is the model number of that drive?  So-called 1.2 meg PC
> drives turn at 360 rpms, but the coco controllers are all timed for 300 rpm
> drives. I just listened to the DSKINI again, and its too slow, indicating
> it may be a 360 rpm drive and is therefore missing every other index pulse.

That one is a drive from Prologica. Model D505/2. Even here I couldn't 
find a service manual of this model.

> I also noticed on the 2nd playback that the head assembly is /not/ moving,
> which it should be a small amount inward with every click you can hear,
> then sweep back out as it starts the verify run.  Can you move it by hand
> when the power is off?

yes, the head doesn't move. I can move it with my hand and the drive 
works fine on the TRS-80.

> At its age, the grease on the heads slide rails could have turned into
> glue, so you'll likely have to grab a can of denatured alcohol, and a
> carton of cotton swabs on sticks, getting it brand new clean and then
> giving the rods a coat of light oil, similar to sewing machine oil.  Move
> the head in and out to get access to the whole guide rod length.
>
> If you have a product called 3in1 oil, thats quite usable.  The spray lubes
> aren't.  They get all over places they shouldn't, and they dry to a wax,
> not an oil film.  Works great for a day, maybe 2, & then stuck again.
>
> And what happens if you push it toward the middle of the disk, power it up,
> and do a dir0?  It should sweep the head back to the outer, track 0
> position, and hammer the stop for a second or so since the coco ignores the
> drives track0 sensor, then step to the middle of the disk to read the
> directory on track 17.

It only moves by itself if I grab the head for the outer edge and make a 
DSKINI, so it starts moving towards the center of the disk, when it 
reachs the center it gives me an IO ERROR.
For what I could understand, the drive head is not being moved at all. 
It only moves to the center if I manually have it positioned before 
doing the DSKINI.


> If it doesn't do as described, start by ditching that cable in favor of a
> straight thru, all teeth present in all 3 connectors version.  I am
> thinking the control signals from the coco are getting scrambled by that
> 'PC' cable.

I have removed that loose end of the cable, but no results so far. And 
the connectors have all teeth.

>
> Please advise the list what you found when you did the exercises above.
>
> Cheers, Gene

Thanks!
Daniel