Osborne 1a - Misc questions

[gimgim]

I went today to a flea market in Cupertino hoping to get some spare floppy drives for the Kaypro II.
I got instead 4 (no kidding!) Osborne 1a in fair conditions (bought also a Commodore Minuteman 1 calculator and a rotary dial channel selector, really nice. Identical to: http://www.ebay.com/itm/ODD-VINTAGE...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557). Two machines also came with software.
There are scratches and discolorations but they all boot. Two have b/w tubes, two the have green phosphors.
From a quick initial look, the machines are also slightly different. One has no video edge connector, one has an RCA connector on the front panel, the other two have the plug (one of the plugs has a RCA video connector for an external monitor). They all boot, two seem to have the drive A either misaligned or dirty/broken.

I have bought them under the (wrong!) assumption that they were using the Tandon TM100. From reading online this doesn't seem to be the case.
Are the drives compatible with the Kappro's ?

One of the video edge connector plugs is missing. Does anybody have a schematics of the plug? The monitor won't show anything without it.

Thanks!
G.

 

[modem7]

One of the video edge connector plugs is missing. Does anybody have a schematics of the plug? The monitor won't show anything without it.

 

[modem7]

Various Osborne 1 technical information can be found [here].

 

[Marty]

Hi All;
Gimgim, Look at the Kaypro technical guide, (look under bitsavers) and it lists the Various drives that will work on the Kaypro.. And see if they match any that you have in the Osborne, But most likely they all should be ok..

THANK YOU Marty

 

[Sharkonwheels]

Osborne ones use Single-Sided drives. If there's a daughterboard on the mainboard, and the FDD cable connects to htat, then it has a double-density upgrade. Most are labelled as such.

As to the RCA connector; this could be something similar to the Nuevo 80col upgrade, or the Osborne ScreenPac 80col upgrade.
Again, you'll find a daughterboard on the mainboard, and the RCA will plug into it, as well as I think the CRT itself.

I have a 1b with a Nuevo 80col upgrade board.

 

[gimgim]

Thank you so much!

No wonder the video wouldn't work without the shunt. Building one looks trivial once you get the right connector.

Some time next week I will take them apart, look at any existing daughter board, and update the thread.

 

[tezza]

I have bought them under the (wrong!) assumption that they were using the Tandon TM100. From reading online this doesn't seem to be the case.
Are the drives compatible with the Kappro's ?

Yes, your standard Osborne does not have Tandon TM100s. I can't remember the exact make of drive off the top of my head. I remember someone on these forums who knows a lot more about drives than I do (Chuck(G) maybe?) once referred to them as "weird". Just how compatible they are with the TM100s pin-wise, I'm not sure.

Tez

 

[gimgim]

Thanks. Yes, from reading a bit, it seems that they are not compatible.
More projects....

 

[dwansmith]

I believe the Osborne 1 used full-height MPI mechanics but with their own logic card and interface. There was no change required to the drives for the double-density upgrade. A daughter board attached to the mainboard did the trick. The Executive used ALPS standard SSDD drives.
Here's pictures of the MPI drive (top and bottom)
http://www.computermuseum.li/Testpage/Osborne-1-FloppyDrives.htm
I also verified from SAMs - Osborne OCC1 - Disk Drive.pdf that the logic board has Osborne silk-screened on the underside. I forget where I got the PDF, but it matched the last drive I played with.

A few of the original O1 drives have been selling on ebay lately. I have found that the 'B' drives are more likely to work than the 'A' drives, probably due to more use of the 'A' drive. You can switch the location of A and B by typing "Shift-" at the ROM prompt, and it will try to boot from the right hand drive.

Good Luck, Don