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Kaypro II floppy mod ?

Jan1980

Experienced Member
Joined
Mar 13, 2015
Messages
72
Location
Germany
Hello.

Before a few weeks, i bought Kaypro II (not 2), the first version. Normally, it has 2 Tandon single sided double density floppy drives. But this one had 2 Shugarts SA465 double sided quad density drives. Of course, it works not in QD mode.
But there is a mod. They soldered cable from Z80 PIO to a logic chip and from logic chip to side select line on pcb floppy cable plug. So, original bootdisk, made with teledisk on ibm 5170, did not work. I checked with logic probe. Side 0 is logic high, side 1 is logic low. After start is first high, then is switches to low to get access to the side 1. I removed the boot eprom an checked the dump. The dump isn´t original. So, i cutted the cable to drive select line and wrote another eprom with original dump. Kaypro starts from bootdisk and works fine in single sided mode.
But of course, i am interestet to get running the computer with double sided bootdisk. I tried different versions from newer Kaypro 2. Not working. Perhaps, anybody knows this mod ? I have seen the same cable connections in a youtube video. But i cannot find this video anymore, otherwise i would ask on youtube.

Perhaps anybody can take a look to the dump !?

View attachment BIOS_U47_bought with custom dump.zip

It would be nice to know, which diskettes i can use with this dump...


THX !!

Jan
 

clh333

Veteran Member
Joined
Feb 22, 2015
Messages
1,427
Location
Cleveland, OH, USA
Greetings. You can find a wealth of information on this site as there are many knowledgeable members who have real experience with Kaypro machines. I suggest for example that you use the search facility to find topics that others may have visited in the past, some of which may include discussions of your own issues. There is one in particular you may find useful: "KayPlus ROM questions".

Each Kaypro machine was composed of a matched set of hardware, software and firmware (BIOS). If you substitute or modify any of these components the other components may have to be modified as well. The modifications you describe may have been made in an attempt to expand the capacity of the drives; there may have been a switch in the circuit to enable or disable reading DSDD disks. In order for this modification to succeed (on a Kaypro II) a modified BIOS must have been inserted into a custom EPROM; there were several modifications, as the discussion above details.

You could search out each of the variations and, with the help of a hex file editor, compare yours to one of the known alternates. If I can find my copies I may be able to complete the task for you but I encourage you to make the effort in any case.

With the machine in its current state; modified, but modifications partly disabled, it is difficult to predict how it will behave. My suggestion would be to return it to OEM status, with no circuit modifications, with a copy of the original KII BIOS in place and a copy of the original KII CP/M system disk to boot from, and work from there. It is possible to make a KII read DSDD disks, but it is not possible for me to say how you can do so with your current setup.

HTH

-CH-
 

ldkraemer

Veteran Member
Joined
Mar 14, 2013
Messages
2,096
Location
Chaffee, MO
I've looked at the Following ROMS and none match what your ROM is.
1. Advent Turbo ROM's
2. KayPlus ROM's
3. MicroCornucopia PRO* ROM's
4. Universal Rom's
5. Maslin ROM's for Kaypro

Each of tese ROM's has ASCII Text decribing what it is. Your's must be some Custom ROM
created by a previous Owner.

I'm thinking CH is correct. Put it back to Original, then decide what Version ROM best fits your
need, and Upgrade the hardware for 2 or 4 DS/DD or DS/QD Drives. I'm sure the Micro Cornucopia
2 to 4 Floppy Adapter Board would work in your (or any) Kaypro. I happen to have one of those
Boards and could copy it to make more PCB's. The Adapter Board supports up to 4 Floppy Drives
in a Kaypro. (I have one SS/DD Boot Floppt Drive (original) and two Teac 1/2 Height DS/DD Floppy's
in Mine.) That way you would just need a new ROM to make it all functional again, with the correct
Boot Floppy.

What do you see for a Signon message when the Kaypro Powers up. How about a few Pictures
of what you see, along with any error messages That might give us a clue as to who created the
Custom ROM. It's unlikely to be the only one that exists.


Larry
 

durgadas311

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Joined
Mar 13, 2011
Messages
1,143
Location
Minnesota
As I recall reading, the QD drives (if by that you mean the very high density 192 tpi drives) were not only problematic but also required special pre-formatted diskettes. I think they could still read standard density diskettes, but not sure just how thorough that support was. Certainly, writing low density diskettes in a high density drive could lead to problems. I'm wondering how a Kaypro II mainboard could work with the high density drives, so maybe all that modification was flaky.
 

durgadas311

Veteran Member
Joined
Mar 13, 2011
Messages
1,143
Location
Minnesota
I've never heard of "stock" Kaypros with 80-track drives. The Kaypro technical manual doesn't describe that. I don't recall any code in their ROM BIOS that supports that. Perhaps that was part of the mod, and the reason for the custom ROM BIOS.
 

ldkraemer

Veteran Member
Joined
Mar 14, 2013
Messages
2,096
Location
Chaffee, MO
Doug,
You are correct for stock Kaypro's, but Micro Cornucopia and also Advent's Turbo ROM both
supported 96 TPI Floppy's. Lots of users upgraded our systems to 4 MHZ and upgraded
Floppy Drives.

Code:
Kaypro II/2 - SSDD 48 tpi 5.25" - 512 x 10 X 40 X 1 = 204800
Kaypro 2X/4/10 - DSDD 48 tpi 5.25" - 512 x 10 x 40 x 2 = 409600
Kaypro, Pro-8 ROM - DSDD 96 tpi 5.25" - 512 x 10 x 80 x 2 = 819200
KAY5  Kaypro Advent TurboROM - DSDD 48 tpi 5.25" - 1024 x 5 x 40 x 2 = 409600
KAY6  Kaypro Advent TurboROM - SSDD 48 tpi 5.25" - 1024 x 5 x 40 x 1 = 204800
KAY7  Kaypro Advent TurboROM - DSDD 96 tpi 5.25" - 1024 x 5 x 80 x 2 = 819200

Thanks.

Larry
 

dittman

Veteran Member
Joined
Jul 31, 2017
Messages
662
Location
Plano, TX
I've looked at the Following ROMS and none match what your ROM is.
1. Advent Turbo ROM's
2. KayPlus ROM's
3. MicroCornucopia PRO* ROM's
4. Universal Rom's
5. Maslin ROM's for Kaypro

Each of tese ROM's has ASCII Text decribing what it is. Your's must be some Custom ROM
created by a previous Owner.

I'm thinking CH is correct. Put it back to Original, then decide what Version ROM best fits your
need, and Upgrade the hardware for 2 or 4 DS/DD or DS/QD Drives. I'm sure the Micro Cornucopia
2 to 4 Floppy Adapter Board would work in your (or any) Kaypro. I happen to have one of those
Boards and could copy it to make more PCB's. The Adapter Board supports up to 4 Floppy Drives
in a Kaypro. (I have one SS/DD Boot Floppt Drive (original) and two Teac 1/2 Height DS/DD Floppy's
in Mine.) That way you would just need a new ROM to make it all functional again, with the correct
Boot Floppy.

What do you see for a Signon message when the Kaypro Powers up. How about a few Pictures
of what you see, along with any error messages That might give us a clue as to who created the
Custom ROM. It's unlikely to be the only one that exists.


Larry

Larry, if you decide to copy the adapter board I'd like to buy a couple.
 

ldkraemer

Veteran Member
Joined
Mar 14, 2013
Messages
2,096
Location
Chaffee, MO
Alphasite,
I sent you a PM.

Jan,
The Shugarts SA465 double sided Drives are 96 TPI making them 160 Tracks.
512 x 10 x 80 x 2 = 819200

So, let's attack this problem a little different. Locate a DOS Computer and Teledisk and/or Imagedisk.
Make copies of your CP/M Floppy's for Backup purposes, and also so we can look at the images
to see what files are on there. By doing this hopefully we can locate the source files that were
used to create the system.

Larry
 

ldkraemer

Veteran Member
Joined
Mar 14, 2013
Messages
2,096
Location
Chaffee, MO
CH,
The Schematic is done and in easyeda. The PCB Layout is done and in easyeda. I double checked
the Pinouts with with the "F" Version Floppy Pinouts and found the Robie and 4-84 series also uses
Pin 4 and Pin 34, which none of the earlier versions used. So, I updated the .SCH and .PCB files
accordingly.

Next, I need to locate my Photo's and compare the PCB Layout to my Original Micro Cornucopia
Circuit Board to double check everything. Next would be the BOM, to locate the additional parts
to assemble the Board.

I guess I need to make a new posting to see what the interest would be for PCB's.

Thanks.

Larry
 

ldkraemer

Veteran Member
Joined
Mar 14, 2013
Messages
2,096
Location
Chaffee, MO
I'm not planning on retiring again after making 20 to 40 or more PCB's.
It's more to support the Older CP/M Machines and keep them rolling with
GOTEK's and the like. If I break even it's a good thing.

Larry
 

haglebu

Experienced Member
Joined
Nov 22, 2018
Messages
117
Location
Germany, Lower-Saxony, Hildesheim
Perhaps anybody can take a look to the dump !?

View attachment 1065225

It would be nice to know, which diskettes i can use with this dump...


THX !!

Jan
Better late than never!
So it's an old 2K BIOS, therefore probably a "Kaypro" BIOS. The string "KAYPRO II" can also be read directly from the BIOS. But it is not 81-149, 81-149B or 81-149C, because the CRC code is different. It is also not a modified B or C version, because here the BIOS message is: "Pease place your diskette in Drive A". With your version, however, it says: "Please insert ...". This is exactly the same message in the original version 81-149. But here, too, the CRC code is different. It could therefore be version 81-149A. I don't have this "A" BIOS for comparison here.

About your MOD. It can only be the SIDE SELECT mod. All Kaypro II mods discussed in the magazine Micro Cornucopia can be found here.

 
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