Jump to content
d_a_parker

Apple IIe DuoDisk only uses drive 1

Recommended Posts

Hello!

 

I recently acquired an Apple IIe with a DuoDisk. The computer seems to work fine, but something weird is going on with the disk drives. It reads from and writes to Drive 1, even when Drive 2 is specified.

 

For example, both CATALOG,D1 and CATALOG,D2 both read the disk in Drive 1 and list its contents.

 

With the DOS 3.3 system disk in Drive 1, I tried running COPYA. I put a blank disk in Drive 2, specified Drive 1 as the source and Drive 2 as the destination. The reading step went fine, but then it tried to format the destination disk and failed because the system disk in Drive 1 is write-protected.

 

I have verified that the I/O card for the DuoDisk is in slot 6 and all of the connections seem fine.

 

Any advice or ideas are greatly appreciated. Thanks!

Share this post


Link to post
Share on other sites

To piggyback on this, I run into this same problem when I try to boot DOS from CP/M (Softcard //e) in DuoDisk Drive 2. "BOOT D2," or whatever the command is, would only boot from Drive 1.

 

Once in DOS, I'm golden--I can do anything I want with Drive 2. But CP/M is giving me static for some reason.

Share this post


Link to post
Share on other sites

Just a quick update: I tried copying a disk using both Copy II Plus and ADTPro. The issue persists. These programs say they are reading/writing Drive 2, but actually use Drive 1.

 

If anyone has any advice on next steps for troubleshooting, it will be appreciated. Thanks!

Share this post


Link to post
Share on other sites

Sounds like a device select line isn't pulling its weight. If its not throwing any other errors... I don't have any hard and fast idea where to start though, it'd have to originate on the controller and run all the way through to the interface inside the duo. Might require some schematic looking.

 

A

Share this post


Link to post
Share on other sites

Never did find the tech note, but check there's no shorts in the cable from card to drive. That might pull drive select permanently up or down depending whats happening.

Share this post


Link to post
Share on other sites

Thanks for the info. I found the 590-0114 cable pinout online, and tested the voltages on the ENBL A and ENBL B lines (DB-25 pins 11 and 8, respectively). I assume ENBL A is Drive 1 and ENBL B is Drive 2. Anyway, I got very consistent results:

 

At Rest (baseline state):

ENBL A = 4.44 volts

ENBL B = 0.24 volts

 

Reading Drive 1:

ENBL A = 0.09 volts

ENBL B = 0.89 volts

 

Reading Drive 2:

ENBL A = 0.09 volts

ENBL B = 0.87 volts

 

I tried reading from each drive using both CATALOG and Copy II Plus. It seems that the voltage drops significantly on A and nudges upward on B in either case. There doesn't seem to be any dramatic difference calling one drive or the other. Is it possible the controller card is messed up? Or maybe the cable?

 

If anyone happens to know the expected results for those lines when reading from each drive, that would be very helpful.

 

Thanks!

Dave

Share this post


Link to post
Share on other sites

If the state of the two lines is the same reading either drive, that could be your smoking gun right there... I'm sorry I don't have the tech details to help a lot more. You could try checking the signal states on the card itself without the drive attached. It might help rule the card out. I'll see if I can find something more useful

Share this post


Link to post
Share on other sites
Thanks, I will test directly from the DB-19 on the controller card when I have time and post my results. I was testing the pins on the DB-25 end while it was disconnected from the DuoDisk, so in theory those should be the values coming from the card, unless something is seriously wrong inside the cable.


I was poking around for more information and I found the AppleService Technical Procedures document for the DuoDisk:




It provides fixes for several problems but not this one. However, it refers to the Apple 5.25-Inch Disk Drive Diagnostic diskette, which I can't find much information about but seems like it might be handy. Does anyone happen to know if there's an image of this disk available for download?


Thanks!

Dave

Share this post


Link to post
Share on other sites
It provides fixes for several problems but not this one. However, it refers to the Apple 5.25-Inch Disk Drive Diagnostic diskette, which I can't find much information about but seems like it might be handy. Does anyone happen to know if there's an image of this disk available for download?

 

Not off hand, that'd be another whole search :) I have a duodisk "guide" in the winds, I'm just awaiting access too, once I have it I'll post. Most of the documents I've seen thus far mostly refer just to the drive mechanisms. Like the one you have there.

Share this post


Link to post
Share on other sites

It turns out that one of my colleagues has an identical IIe with a DuoDisk, and both drives work fine. We're going to test the line voltages on that one, and then I'll have something to compare my results to. Hopefully this will at least narrow it down.

 

Things are looking less hopeless!

Edited by d_a_parker
  • Like 2

Share this post


Link to post
Share on other sites

Assuming you're using the DuoDisk controller card and not the standard disk controller card? I saw one of these on shop goodwill.com and wondered if the standard disk controller card would be a problem?

Share this post


Link to post
Share on other sites

Hi All,

 

I finally got around to testing the DuoDisk and controller that my friend loaned me. They are the same card but different revisions:

 

Mine = 655-0101 B

Loaner = 655-0101 D

 

There is definitely something wrong with my controller card. My DuoDisk and cable work fine on the same computer when attached to the loaner card. Here are the test results:

 

MY CONTROLLER

 

Baseline:

ENBL A = 4.44 volts

ENBL B = 0.24 volts

 

Reading Drive 1:

ENBL A = 0.09 volts

ENBL B = 0.89 volts

 

Reading Drive 2:

ENBL A = 0.09 volts

ENBL B = 0.87 volts

 

 

LOANER CONTROLLER

 

Baseline:

ENBL A = 4.49 volts

ENBL B = 4.49 volts

 

Reading Drive 1:

ENBL A = 0.09 volts

ENBL B = 4.47 volts

 

Reading Drive 2:

ENBL A = 4.47 volts

ENBL B = 0.09 volts

 

So, the ENBL B line is being pulled down all the time. On the working controller, the selection line for the target drive goes low and the other one remains at roughly the baseline voltage. But on mine, the ENBL A line goes low no matter which drive is requested, and the ENBL B line isn't even close to the correct baseline voltage to begin with.

 

Does anyone know of anything on the card that might cause something like this?

 

Thanks!

Dave

Edited by d_a_parker

Share this post


Link to post
Share on other sites

I took an apple iie and turned it into a raspberry pi machine. I removed the 19 pin cable from i/o controller board though. You would have to remove your cable and pop it on this one but you can have the board for the cost of shipping.

 

post-30773-0-02155600-1552613180_thumb.jpg

Share this post


Link to post
Share on other sites

Thanks! If shipping is cheap enough I will certainly take that deal. Can you PM me and we can figure it out?

Share this post


Link to post
Share on other sites

Yep! It certainly seems my old board is defective, because the DuoDisk is working correctly with the new one. Some of the chips on the old board are in sockets, so I may try swapping those out if I come across any replacements.

 

Thanks!

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...