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SomeGuy
March 20th, 2014, 12:45 PM
Does anyone know the proper way to disassemble the screen on a Kaypro 2000?

Funny thing is I managed to get it partially apart many, many years ago when it first developed its problem with the screen, but I don't recall how. There are no visible screws anywhere, on the screen/lid. I'm thinking it snaps together, but I'll probably break it.

I do recall that the problem is that the flat cable that runs from the motherboard in to the screen is supposed to connect to the LCD panel with an adhesive, but came partially undone. Pressing on it would make it work.

Does anyone know a good way to re-attach such a cable?

I had put the repair of this off because it had a second, unrelated problem. The floppy drive had stopped working some time prior. However, recently I took a chance and discovered that a Citizen OMDT-23A 720k drive parted out from a Zenith ZFL-181-92 is a suitable replacement for the Kaypro's Citizen OMDT-11A 720k drive. (Oddly it seems like a number of ZFL-181-92 and parts have popped up on eBay lately)

For the first time in ages, I was actually able to boot the Kaypro, and access MS-DOS via the serial port! Now that I can boot it, I'll go back and do some more tests on the old drive once I can see what is on the screen.

So any ideas? This case has got some crazy Japanese engineering going on here.

SomeGuy
March 22nd, 2014, 02:06 PM
No ideas? :( So close...

Fezzler
March 22nd, 2014, 06:36 PM
You have to peel the plastic boarder off.

SomeGuy
March 24th, 2014, 03:58 PM
You weren't kidding. The plastic strips along the top and bottom are glued on there and cover the screws. I guess I'll have to figure out how to re-attach those later.

But the good news is, the problem is just the flat cable that connects the motherboard to the monitor. With the cover apart I was able to check continuity, and the second pin from the right had nothing. Touching a wire between the motherboard and the screen for that bad one, and I could read the screen again!

BTW for Modem7: the display does indeed show "j.08x" as the BIOS version at boot.

17947

So is it possible to get a replacement connector like this anywhere? It seems to be 1 5/16 inches wide and 8 1/4 inches long with 12 wires.

I think I see where it is broken. There is a crease on the lower end just above where it connects to the motherboard.

Chuck(G)
March 24th, 2014, 04:26 PM
I assume that you mean the flexible flat cable (FFC) and not the connector. Yes, you can buy the stuff in bulk, but that isn't going to help you to prepare the ends for insertion. Your best bet, short of getting a replacement that works, is to patch the break using either a copper or silver repair pen (scrape the insulation off the area that needs patching or solder a piece of fine wire to do the job. I'm guessing the pitch of the cable is 0.10"...

SomeGuy
March 26th, 2014, 12:54 PM
Well, my attempt to repair the cable has failed. It looks like most of the other conductors at the crease (and perhaps at another crease as well) have broken now. Leaving me with one end mostly melted with solder patches. Because of course, I can't do anything right.

Fezzler
March 26th, 2014, 05:45 PM
http://stores.ebay.com/excell-electronic-excell

Perhaps here?

SomeGuy
March 27th, 2014, 02:06 PM
Is "pitch" the distance between the center of each conductor/wire? If so, then this would be a 12 conductor 0.10 inch or 2.54mm pitch Flat Flex Cable. And I'm not seeing any of that kind out there. (I guess everyone went to metric and I didn't get the memo) On top of that the "termination style" is exposed conductors on opposite sides.

SomeGuy
April 4th, 2014, 02:37 PM
A little update, it feels like I have dragged this thing back from the dead kicking and screaming. :frankenstein:

There was a little bit of extra slack on the cable, so I just cut off the damaged end, scraped off some insulator, shoved it in the socket, and after some futzing, it seems to more or less work. But... just as it looked like the screen was going to work, the keyboard stopped working! I got lucky and traced the problem to a dead 74c914 on the motherboard, and was able to find a new chip on eBay. Must have zapped it while plugging in the keyboard.

If I ever have to unplug that video cable again, it will probably all fall apart, but for the moment it is working.

18119

BTW, tried running Nyan Cat on here, but the CGA emulation interprets color characters as either all black or all white instead of grays so you can't see much of anything.

Also, with this new floppy drive it can successfully boot later versions of DOS (6.x) without any hacks. The old drive required a lower step rate than what regular MS-DOS defaults to.

Fezzler
April 5th, 2014, 08:05 AM
Great job. I don't know why, but I like these old, odd Kaypros. I have a K2000+ I'm trying to get going. I think it needs a new battery, but nor sure. I also need the specific boot disk for it but I can't seem to find it. For years in te 80's the Kaypro you have with the docking bay used to be my main PC. 20 meg harddrive and CGA color. I thought I died and went to heaven. All that space and color. And no more disk swapping. And 2400 bps modem!

pcat
December 10th, 2014, 09:12 AM
I recently decided to attempt to revive my Kaypro 2000 and have run into the same problems as SomeGuy. Thanks for the lead on an alternate floppy drive, I'll be on the lookout for a Zenith to cannibalize. I did find that original Kaypro drive could be made to work with DOS 3.3 by patching the OS (DOS 2.11 which came with the 2000 was apparently customized to work with the OMDT-11A drive.) I am also looking for the LCD cable. Thanks to Fezzler I at least have some additional info to go on. Unfortunately, excell-electronic (on ebay) doesn't seem to have cables with the right pitch. From my measurements I think it should be a 2.54 pitch, 12 conductor cable, 33 mm wide. I also attempted repair by cutting the cable short and the baring the conductors but haven't gotten a good connection yet. I actually have 2 2000s, I bought one back in the 90s to use for parts (disk drive) to fix my original machine. Ironically, that "parts" machine is now working while I work on the cable problem on the other.

gjwatson
October 27th, 2015, 11:42 AM
Does anyone know the proper way to disassemble the screen on a Kaypro 2000?

I had put the repair of this off because it had a second, unrelated problem. The floppy drive had stopped working some time prior. However, recently I took a chance and discovered that a Citizen OMDT-23A 720k drive parted out from a Zenith ZFL-181-92 is a suitable replacement for the Kaypro's Citizen OMDT-11A 720k drive. (Oddly it seems like a number of ZFL-181-92 and parts have popped up on eBay lately)
.

(Yes, I know this thread is a year old, but I want to reply directly to an aspect here to ask a question.)

SomeGuy was very kind in providing detailed parts information. I just acquired a Kaypro 2000, I think the drive has problems, it will start reading the hidden MS-DOS boot files, giving the copyright information from Microsoft, and then start making grinding noises before saying "bad or missing command interpreter". It says this on multiple different disks.

Following what SomeGuy wrote, I found one of the Zenith machines on eBay with the drives and have just ordered it. But does anyone have any suggestions and/or instructions of how to get to the drive to take it out or things to be careful of? Thanks. My Kaypro II'83s are a bit easier.... :)

The machine didn't come with a power supply, but I was able to get it working with a power supply at 7.5V, 2A, with negative tip polarity. The machine goes through the POST fine just up until it is reading the disk.