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.