Monochrome DEC Rainbow keyboard and video cabling options

[aperezbios]

I picked up a DEC Rainbow PC100-B2 for free at this most recent VCF West show, and it has a 10MB MFM HDD, no color video option, and no cables of any sort.

I've got DB15 video cables I can hack up, and I understand this thing can output monochrome composite video. I have a couple of displays which can accept composite via a BNC input, but I also need to fashion a breakout cable for the keyboard. I have an LK401 keyboard, which should work, assuming I can fashion an adapter.

I found this old archived VCFED thread here, which looks like it may have contained the information I am looking for now, however it's long gone: http://www.vcfed.org/forum/archive/index.php/t-39297.html

 

[DECtechGuy]

I went through this just a few days ago, but in the process I blew up an LK401....

Find a copy of the Rainbow Technical manual from May 84 (EK-PC100-TM-001) and find table 3-6 for the video/keyboard pinout.

You'll want pins 12 and 4 for mono video source and mono ground. Then for the keyboard; pins 7, 5, 14, and 15 for the +12V, Ground, Keyboard Receive and Keyboard Transmit respectfully.

For the keyboard find any phone jack and wire up those 4 pins correctly. This is the example pinout I followed for the jack: https://www.netbsd.org/docs/Hardware/Machines/DEC/LK201_connector.jpg

The DECstation pinout is what you'll be wanting to follow. Check your work over and over again before you try it, because like I mentioned, I blew up an LK this way.

 

[Lou - N2MIY]

See the little box in this album that was discussed in my original thread of many years ago : http://www.vcfed.org/forum/album.php?albumid=204&attachmentid=14602 . Notice the phone jack on the side to plug the keyboard into. The little box plugs nicely into the back of the Rainbow (http://www.vcfed.org/forum/album.php?albumid=204&attachmentid=14603). The pinout can be found online with a trivial amount of time spent with Google.

Lou