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picking an Osborne 1

KennyPowers

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Jun 16, 2021
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I'm going to meet a guy tomorrow who says he has six Osborne 1s that I can take my pick of, and at least some (maybe all) of them boot and read disks. I own and have restored two Osborne Executives, and I'm familiar with the major differences between those and the Osborne 1. I also know there were two case designs for the Osborne 1, and I believe these are all the later design (same case as the Executive). Are there any common features or upgrades I would be able to identify just by looking at them in case they aren't all the same? Is the black/white or black/green screen rarer or more desirable than the other? I know some Osborne 1s were upgraded with double-density drives, but I kind of want one with single-density drives because my Executives already have double-density drives. Is there any way to tell what type of drives they have besides trying to read a double-density disk and seeing if it works (not sure I want to stick any of my disks in an unknown drive)? Any general tips or things to look for? Thanks!
 
As far as I know, all the later Osborne 1's have the double density option fitted and it was an optional upgrade on the earlier ones. As for the screen, I don't think either is rare. I've seen a good mix of white/green. Personally, I prefer the green :)

Things to look for are composite video output connectors that have been added. This can be a sign that the machine has also been fitted with an 80 column board.

Cheers,
Dave
 
I'm going to meet a guy tomorrow who says he has six Osborne 1s that I can take my pick of

I am so envious of you :(

LoL! But If you ever come across an extra Osborne Executive for a decent price and will ship to Australia I'll change my mind ;)

OK, here's what I discovered.

1) -The Power Selector. Check at the back and slide the plastic cover to the side and confirm it's set to 120 not 240. There should also be a little card in there that can be removed (with difficulty and a lot of force, but it is designed to come out ) that changes the voltage selector from the back. The fuse ejector must be completely to the left and the fuse gone to remove it though. Make sure it's there so you can go multivoltage easily.

2) Get 2 new 0.01uF and 1 new 0.1 uF "Rifa" caps for the PSU. You WILL have to change these. They are ALL bad and way past their use-by date. They will burn and may cause further PSU damage. See the threads on the topic. If you can't change them yourself, find someone else to.

3) If it's running, check that both drives are working. You can boot of B: by SHIFT " (quote key).

4). Get a small torch. Look through the front cover. A multicolored ribbon cable just beneath and to the right of the monitor is a good sign the screen-PAC (80 column) PCB is installed. It sits about 3/4" above the main PCB. There should also be a RCA video-style connector on the right, just to the right of the reset switch.

5). Look through the the far right air grill, all the way to the back where you can see the 6 pin power connector stuck into the mainboard. If there's another upper-mezzanine PCB right next to it, likely with a standoff plastic insert holding it up, that's the Double Density adapter. It will sit right at the back, so there might be the extended screen-PAC L-shape PCB in front of them. Without that, you can't read Double Density disks.

6). Make sure the video shunt is installed on the lower left to take the video to the screen ( you won't get video without it ).

7) Some models came with a modem in the disk carrier slot.

8) Make sure the keyboard works, plugs in well and all the keys work acceptably.

9) Look to see if the screen is up against the front cover, of if there's a plastic diffuser there. ( There should be a plastic diffuser ).

10) Make sure both the brightness and contrast knobs work well and turn well. They are friction-fit only in the Osborne 1B.

11) Check the carry handle - look for good leather surface and no cracks.

12) Make sure the vent on top disengages and slides out easily enough, but remains stowed when closed.

13) Look for any gaps along the back where the clamshell case joins. There should be none, but the handle shifts when you open it and sometimes people forget to realight it before screwing it back up.

14) Take the torch and inspect all of the screw holes front and bottom. Make sure none are rusted. All should be black and show no signs of damage. They are a pain to drill out if they are stuck or rounded.

15) Check the plastic clamps ( like the Exec ) - lift them right open and inspect where they join and the plastic is thin. With a little ( very little ) side to side force, check for any cracks in the plastic.

16) Look for anything that comes with it - eg, Cables, books, Printer cable etc.

17) Inspect the case for any general damage and yellowing.

18) See if the original power cord is coiled up in the rear power compartment.

19) Make sure the rear power cover has both tabs intact, seals and opens OK and opens and closes easily.

I think that's all I can think of to check as a quick internal inspection. :)

Regards
David
 
I am so envious of you :(

LoL! But If you ever come across an extra Osborne Executive for a decent price and will ship to Australia I'll change my mind ;)

OK, here's what I discovered.
Thank you! Exactly the type of info I wanted. I'm familiar with RIFAs having restored many older computers, so it's always scary powering these things on to see if they work prior to purchasing. I did full recaps of both Executives amongst a lot of other things. I don't know what shipping a fragile, heavy computer from the US to Australia entails, but it doesn't sound cheap or easy :(
 
Well the seller had kind of picked one out for me already, but according to them, the ones they were willing to part with were all bog-standard Osborne 1's without any upgrades, and the one they had set up for me worked well and didn't have any broken plastic, rust, or cosmetic issues that a bath and retrobright won't fix. So here she is at home next to one of her Executive big-brothers:

PXL_20230525_193123416.jpg PXL_20230525_193112476.jpg

Not going to turn it on anymore until I can open it up and replace any RIFAs (if not a full re-cap while it's open). It does not appear to have the double-density upgrade, which is fine...I have the Executives for that. Serial number is 122798...looks like it was manufactured in December of 1982, making it a year and a half older than me :)
 
That's a good sharp monitor image and it looks like it's in nice working order. :)

I'm halfway through repairing my latest osbornes - Getting a working one is especially nice. I saw the microsope on the shelf so I assume you do your own PCB repairs anyway, but it's still nice having it work as it should on power up :)
 
Ya, I've done a fair bit of PCB repair on other systems...usually Macs with damage from their notoriously leaky surface-mount electrolytic caps or batteries, but thankfully these machines don't have either of those things, so I haven't yet encountered any damaged PCBs in them. Of course, individual components going bad is always a possibility...
 
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Are you planning to install a Gotek? Or just keep it original with the two FDDs?
I plan on doing a full resto on the original hardware before possibly adding any modern amenities like a Gotek. I may go that route though since I don't have any physical disks for the O1 like I do for the Executives (I have a bunch for those...flux-imaged them all first thing). I'm making a couple disks for the O1 though so I can test it. I downloaded the IMDs from Dave Dunfield's site and converted them to Kryoflux stream files with HxC. Now I just need to dig out my Kryoflux and open up my DaynaFile since that's where my only 40-track drive is :rolleyes:
 
I plan on doing a full resto on the original hardware before possibly adding any modern amenities like a Gotek. I may go that route though since I don't have any physical disks for the O1 like I do for the Executives (I have a bunch for those...flux-imaged them all first thing). I'm making a couple disks for the O1 though so I can test it. I downloaded the IMDs from Dave Dunfield's site and converted them to Kryoflux stream files with HxC. Now I just need to dig out my Kryoflux and open up my DaynaFile since that's where my only 40-track drive is :rolleyes:

As an option to consider, if you install the Gotek, even temporarily, you can boot off the Gotek and write bootable disks straight onto Drive B without difficulty. The Osborne makes it easy to format and copy disks. I did that then sometimes I boot off of the Gotek and sometimes boot off of the B: Disk Drive ( you can software swap the drives at boot time).

See if it has the DD adapter installed too. If not, then you can always make one. As I mentioned earlier, it's possible to check if it's there by shining a flashlight into the front slots and peering in on the right side.
 
As an option to consider...

If I already had a Gotek, I would probably do that, but I do already have all that other stuff, and isn't part of the fun figuring out overly-complicated, MacGyver-esque ways to do something that make me feel clever? :)

I'm pretty sure it doesn't have the DD adapter. Not only do I not see any boards attached to the mainboard when looking through the front, but I brought a known-good DD disk with me when I bought it, and it wouldn't read it, but it did read SD disks the seller had (he wouldn't sell any of them or make copies).
 
Love the list provided by @cj7hawk!
I got my hands on a very early Osborne 1 last year, serial no. 002369, and did some repairs to it before passing it on. Some of my write-up here might be useful.
 
Smoke test after a complete recap of the power supply, CRT, both drives, and main board...looking good!

PXL_20230611_220933719.jpg

Now to wash out all the spiders, de-yellow the plastics, and make it look as good as it runs :)
 
All done! I replaced all of the electrolytic capacitors in the entire machine, adjusted the drive RPMs, de-yellowed the plastic, and thoroughly cleaned it inside and out. Looks and runs like new!

PXL_20230711_194122039.jpg PXL_20230711_193938944.jpg PXL_20230711_193522160.jpg
 
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