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saundby
June 6th, 2010, 12:15 AM
I got a new desk this week that's a little wider, so I had enough room to bring my VT-102 out of the garage and swap it in for the not-as-nice ADDS 2020 terminal I was using.

Unfortunately, while the VT-102 display is much nicer than the ADDS, the characters are currently taller on the lines at the top of the display than the bottom. I'd like to fix that.

Does anyone know where I can find a service manual that tells me which pot to tweak? I didn't see one on vt100.net, though I may be overlooking it. Or if someone can give me a component number. It'd be nice to go right to it without having to hand-over-hand my way through the circuit cards. Oh, and yes, I am checked out to work on high voltage systems. ;)

Lou - N2MIY
June 6th, 2010, 05:53 AM
My VT102 uses the same RS-170 video board as the VT100. This is the board that the wiring from the neck of the tube runs to.

Download the copy of the VT100 technical manual (EK-VT100-TM-003) that is out there (bitsavers - http://www.bitsavers.org/pdf/dec/terminal/vt100/). Read the section on the video adjustments. You need to adjust R342, the vertical linearity control. It's all there in the manual on page 5-33 and you will have the chartacter height issue straightened out in no time.

Be aware that there is discussion of two different video boards. One was from Ball (of mason jar fame) and the other was DEC/Elston. I'm pretty sure that the VT102 had the DEC/Elston version.

Lou

PS, if anyone ever comes across the VT102 field maintenance print set, I would surely like a copy.

saundby
June 7th, 2010, 11:32 PM
Great! Thanks a lot, that did the trick. The display is back to looking Dec-spec again.

JeanColorado
June 28th, 2010, 10:38 AM
http://vt100.net/docs/tp83/chapter6.html
I have a DEC VT 131 that needs a new home. I found this site looking for information on it.
thanks,
Jean

Lou - N2MIY
June 28th, 2010, 03:19 PM
Jean,

The VT131 is a very nice terminal. You should consider keeping it. There is a good bit of dec gear in Colorado, so you should look for a nice pdp 11/23 /53 /73 to go with it. The setup won't take up too much room in your house. This picture has a VT100 sitting on top of a micro 11/73 http://www.vintage-computer.com/vcforum/album.php?albumid=53&attachmentid=2755. The VT100 has the same style case as your 131.

Lou

JeanColorado
June 28th, 2010, 03:58 PM
Lou,
thank you for responding. I really do need to send the VT131 to a new home. I will be moving in the next 6 months and there won't be a computer person in the house. Some of what I have I can give away, some I would like to sell quite simply because I need the funds. Hopefully someone will want the VT131.
Jean

Lou - N2MIY
June 28th, 2010, 04:23 PM
Jean,

Without a doubt, your terminal will find a new home. You may also want to post on alt.sys.pdp11 since it's the right vintage to go with a newer -11. Best of luck with your move and everything else it sounds like you're dealing with.

Lou