[Coco] Help with my CoCo FDD

Mon Nov 19 03:35:15 EST 2018

On Monday 19 November 2018 01:21:36 Walter Zambotti wrote:

> >This has the quack and waddle of two ducks, both wanting to be first,
> > drive 0.  >From prior experience the first thing I'd do is look into
> > the edge connector pulled >off either or both drives. Missing teeth?
> > then both drives need a jumper on 0 (1) >2 3 MX Term 0 (1) 2 3 MX
> > Term because the twist in the cable makes the 2nd >& last drive into
> > drive 0, and in any event you'll need a jumper on Term for last
> > >drive on the end of cable.
>
> Thanks Gene
>
> I should have said I have backed off from trying to get both drives
> working together and all my testing was just with 1 drive at a time.
>
> So if I only have 1 drive connected then I should just need a jumper
> on 0 & Term!
>
> However one of the drives only spins up when I jumper MX even when
> it's the only drive!  I'll check the edge connector.
>
With the factory cable, the end connector is drive 0, but it needs a 
jumper set for drive 1. The twisted part of the cable makes it drive 0. 
the drive set as drive 1 is then the middle connector and will be drive 
1. Stuff is numbered in base 0. Make that drive work by itsself on the 
end of the cable, and verify that a dir(1) doesn't light its access led, 
but does run the motor. You might have to use some contact cleaner and 
some newspaper to clean the card edge patterns on the drives, clean 
until the newspaper stays clean if you get some fresh paper, wet with 
cleaner and go back again, pinching the paper against both sides of the 
contact, particularly if it looks to be solder plated. If gold, its not 
very thick so be more gentle. At the cables age, if you can see a space 
in the cable to connector joint, don't be afraid to stick it in a vice 
and clamp it tight again. Its now 30+ years old and a lot can happen to 
an insulation displacement connector with that sort of age on it.  Where 
the internal fingers punch thru the wires  as they are pressed into the 
slit in the contact pinching and connecting to the wire was never what 
we'd call a gas tight joint to start with. So oxygen from the air we 
breath does get in to oxidize things. You may find its bad even after 
the trip to the vice, so don't be surprised if you have to order up 
enough of those connectors and some 34 conductor cable to make a newer 
one. 

I've had to do it 2 or 3 times now with the db25's used to drive my shop 
cnc machinery at less than 10 years. Thats a much dirtier environment 
though. Cutting oils and "swarf", aka the metal cuttings, can get into 
the darnedest places. Biggest problem is the keyboards, so a lot of this 
stuff does have a mouse or keyboard, but a touch screen. But BIG touch 
screens cost too much, so I've resigned my self to losing at least a 
keyboard a year somewhere in the shop.

> I'm going to get my Tandy ctrl and drive out of storage and test that.
>
> That should at least prove the CoCo is not the problem.
>
> Walter

Good idea.

> > -----Original Message-----
> > From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Gene
> > Heskett Sent: Tuesday, 13 November 2018 1:11 PM
> > To: coco at maltedmedia.com
> > Subject: Re: [Coco] Help with my CoCo FDD
> >
> > On Monday 12 November 2018 23:32:03 Walter Zambotti wrote:
> > > Hi guys
> > >
> > >
> > >
> > > Advance help request.
> > >
> > >
> > >
> > > I was cleaning up my FDD and a jumper fell out (from I don't know
> > > where!) And there are numerous jumpers on the FDD and I don't know
> > > where to put it back.
> > >
> > >
> > >
> > > After that I can't read any of my FDs!
> > >
> > >
> > >
> > > I'm going to take a few pics of the thing and post them online in
> > > the hope one of you guys might be able to help!
> > >
> > >
> > >
> > > Walter
> >
> > Panasonic did at one time have that stuff on the web as .pdf's. But
> > that was 20 years back too. I have an earlier factory manual on the
> > JU-455, but its not that new so the pcb is probably different. But
> > set that one on your scanner glass, and send me a PM as a 
> > multimegabyte jpeg, with the scanner running at at least 600 dpi, so
> > I can compare it with what I have. Send it to me, not the list as it
> > will be huge.
> >
> > --
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > Genes Web page <http://geneslinuxbox.net:6309/gene>
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco
>
> --
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco

-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>