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Osborne 1 not reading disk

schreibstang

Member
Joined
Oct 8, 2013
Messages
11
Location
WA, USA
I was lucky enough to be given this Osborne 1 today, in very good physical shape. When I turn it on, the screen flickers (extremely low refresh rate you could say) and I can't read the disk it came with. (Not a system disk but the drive doesn't even attempt to read). When I unplug the keyboard, the screen stops flickering. I was told that, speculatively, it might be a power supply issue, and that makes sense since they seem to be a common issue. Any ideas?

This is my first really old computer in the sense of using an operating system and disks completely unlike anything I was used to growing up (in the 90s) and though I have a good knowledge of PC history, I don't know too much about technical aspects of computers this age. XD

DSCF8453.jpgDSCF8461.jpg
 

billdeg

Technician
Joined
Nov 18, 2003
Messages
3,872
Location
Landenberg, PA USA
First clean the drive heads to be sure you don't simply have a dirty drive. There are how-to's on the web for cleaning a drive head using isopropyl alcohol and a q-tip.

If that does not work, try booting from the right drive by pressing SHIFT+" (shift doublequote) just before the system attempts to load the OS from disk. Shift + " causes the system to actually swap drive assignment, (a=b , b=a).

Circling back to the orig problem, don't assume the disk is good, you may have a bad disk. I'd try a known working boot disk before you assume you have a hardware problem.
 

schreibstang

Member
Joined
Oct 8, 2013
Messages
11
Location
WA, USA
I'm starting to think I worded that pretty poorly. It isn't not reading a disk; the drive doesn't do anything at all when I hit return, hence the "attempt to read" which really means it's not working.

I tried shift+". It turns on, the floppy drive indicator lights both flash and I hear a little click from each. Then when I press return, neither floppy drive activates (whether the boot drive be a or b). The odd thing is that the screen stopped flickering on its own with the keyboard still plugged in after sitting for a few minutes. The problem seems to be really erratic so I thought power supply issue might make sense.
 

ppcmini

Experienced Member
Joined
Jan 18, 2014
Messages
104
I would take the unit out of the cae. Then pull off and re-insert all connectors. Corrosion and losse connectors cause havoc. Also push down on the chps.
Mike
 

curtis

Veteran Member
Joined
Apr 30, 2003
Messages
1,176
Location
Amarillo, TX
The drive problem sounds like the addressing is incorrect. Might need to check to see if the jumpers on the A drive is different from the B drive. I'm willing to bet they're both jumpered the same given your symptoms. It's been a few years since I've been in mine, but IF I remember correctly, the A drive should be jumpered as 1 and the B drive as 2 with a straight through cable.

As far as the flickering, that may be dying capacitors in the power supply.
 

modem7

Veteran Member
Joined
May 29, 2006
Messages
7,896
Location
Melbourne, Australia
The drive problem sounds like the addressing is incorrect. Might need to check to see if the jumpers on the A drive is different from the B drive. I'm willing to bet they're both jumpered the same given your symptoms. It's been a few years since I've been in mine, but IF I remember correctly, the A drive should be jumpered as 1 and the B drive as 2 with a straight through cable.
Some Osborne 1's use the 'standard' drive-select methodology (I have one), but I understand that the norm is the use of Osborne-custom floppy drives (drives with a custom board) resulting in drive selection done purely by the location of the resistor pack.
 

acollins22

Experienced Member
Joined
Mar 12, 2007
Messages
248
Location
Leicester, UK
Hi,

The screen flashing sounds just the same as the problem I had when I first got mine.
It turned out to be a sticking key on the keyboard. IIRC It asks you to press return but if any other key is pressed it just clears the screen ans asks again. So, if a key is jammed, it will just keep flickering but also, it won't be able to see the retrun key.
Work your way across the keyboard pressing each one and see if you can unstick it.


Cheers,

Andy.
 
Last edited:

schreibstang

Member
Joined
Oct 8, 2013
Messages
11
Location
WA, USA
Hi,

The screen flashing sounds just the same as the problem I had when I first got mine.
It turned out to be a sticking key on the keyboard. IIRC It asks you to press return but if any other key is pressed it just clears the screen ans asks again. So, if a key is jammed, it will just keep flickering but also, it won't be able to see the retrun key.
Work your way across the keyboard pressing each one and see if you can unstick it.


Cheers,

Andy.

I think your idea is closer to solving this than any others mentioned so far! But it's not solved that simply.

I got this to boot, actually. While I was trying to un-stick keys, I randomly smashed my hand across the keyboard and got it to boot to the disk in the drive it came with. I figured out the command is ctrl-m. After it boots (really quickly to an A> prompt) 7 keeps getting typed over and over. I can type on all the other keys (including return) and they work but the 7 is always being typed. I can't seem to un-stick it, unfortunately. But now I know where to focus my efforts.
 
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