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Osborne 1 -- internal CRT does not work/power, but external does

Well done.

Now you have 'fixed' the cable, the firmware is probably seeing a shorted out key that results in an invalid character. As a result, the screen clears and the boot image reappears. This repeats indefinitely. This gives the impression of a flashing/flickering screen.

Dave
 
A5/D3 space bar seems shorted (so far). that membrane looks like there is no return once I start. key plungers are melted in place from the bottom, so I guess I can pull it off. don't think I have many options.
 
That is the usual keyboard fault - unfortunately..

You can either wait for a working keyboard to appear on eBay (they do come up occasionally); or someone on VCFED is trying to manufacture a new one...

Dave
 
wasn't too bad for a fix, but time will tell. I read in a thread on here a tip to use low heat to reform/pop out the stuck membrane. trimmed the melted blobs to release the key switch (only one since there's nothing near the space and spun it around to reveal membrane), meter connected to hear continuity, light heat on about 150 and the tone went away in about 10 seconds of heat. keyboard works fine for booting, as does enter for disk boot.
 
very basic question on usage/CPM.

I have a gotek as A with the system disk image and a floppy as B.

boot to gotek, copy.com, I get the format option. I inserted an unknown floppy (possibly 2SDD) in B and format. the program counts across 0 to 39 and puts an E under each track. At the end it says format error.

given that I have the enhanced disk card, any suggestions on how to format and/or test the floppy drive?
 
You can use the utilities on the Gotek boot disk to format and copy the new disk in the B drive. If the process fails, you can be sure there's a problem. Make sure the disk speed is correct and that the worm drive is lubricated, and you may need to make sure the bearing on the plastic disk axle on top is cleaned and relubricated.

Also make sure the heads are clean. My O1 disk drive shredded some old disks and the surface remained on the heads and damaged other disks and prevented use.

Also, make sure the B drive DOES NOT have the resistor pack installed. That's for Drive A.

Once you can format a disk without issues, then copy the boot disk to the B: formatted disk.

After that, you can boot the Osborne 1 from the B: drive ( It swaps A and B so that the Gotek becomes B: ) - I think it's Shift = or Shift " that does it. The key just above the enter key and Shift. that tells the Osborne 1 to swap the select lines. THIS ONLY WORKS AT BOOT TIME and stays as selected until you reboot.
 
thanks. these are customized osborne floppy drives (not swappable with a Tandon/TRS-80/etc drive? Would mine be SS DD? does diskette type matter?

I am using the B drive without resistors. and FYI, I noticed the A drive had a 7400 chip U17 that was extremely fire hot. B drive feels normal.

EDIT: the copy from A gotek to B floppy WORKED using my B drive!!!
 
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Yes, Osborne made up their own circuit board to drive them. Mostly it's the same, but it has an extra clock signal and also both 5v and 12v are carried in the cable where most drives have grounds.

The drive is the same whether SS or DD, since it's the encoding method that makes them different. The extra DD PCB on the main computer board makes them DD. Otherwise they are SD.

There are some notes on troubleshooting the drives elsewhere.

I did find that some of the disks I tried to use with my Osborne drive were a little difficult for it to format... I had to degauss them before I could format them - after they they formatted fine. Might be a coercivity related problem.

I got some new (old) Double Density disks and they worked fine straight out the box. I never tried HD disks - they might not work. If you have old original disks, it is suggested to use a lubricant - Cyclomethicone is recommended as it is volatile and will evaporate entirely in time. A drop of it on the underside then work into the disk should be sufficient to help protect the disk.
 
I'm subscribed to that keyboard thread. looking forward to it.

I have since picked up a couple more Osbornes (these things are surprisingly inexpensive relative to others in this vintage) and will definitely get some keyboards. also just ordered another gotek board from you.
 
Finally had time to put the O1 back together.

Thanks to kc4bqk for the keyboard shunt repro and the gotek adapters. and thanks to cj7hawk for the excellent floppy drive 3d models.

Seems to be fully working with Gotek A and floppy B. I need to address the carry handle and the frayed keyboard wrap/loom at some point.
 

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