VOGONS


First post, by 90skidJohnny

User metadata
Rank Newbie
Rank
Newbie

Howdy all. Recently found a really good deal on a Tandy VN-1 Monochrome green monitor. Love the aesthetics of it! Seems like it should be working however i bought this untested.

Anywho, finally getting around to messing with it and busted out my TRS-80 and noticed that the Monitor uses an 8 pin Din, while the TRS-80 Uses a 5 pin din. This VM-1 was a monitor i believe that was specifically for the Tandy 2000.

Anywho, From the pinout I can find, The 8 Pin Din on the monitor is as follows.

1 - Not Connected
2 - Ground
3 - Intensity
4 - Horizontal Sync
5 - Vertical Sync
6 - Not Connected
7 - Video Signal
8 - Not Connected

Pretty simple stuff. All makes sense to me. But, the TRS 80 with its 5 pin, seems to basically be just - Composite video - ground, and voltage (5v DC)

So since this monitor "Requires" bother Horizontal and Vertical Sync, could I not just pump the composite video to the Vertical Sync / Horizantal Sync / Video signal Pins? Im not sure if it is that simple or if im missing something. I would love to be able to use this monitor on both my TRS-80 and Apple IIc (Which basically just uses composite video as well)

Any one that can chime in with any info would be super awesome. Thanks! Be Safe everyone!

Reply 1 of 5, by VileR

User metadata
Rank Oldbie
Rank
Oldbie

As far as I know it won't work with those machines. The Tandy 2000 outputs either 640x400 or 800x400 (depending on the adapter), so this monitor is designed for a 26.4KHz horizontal frequency, which is much higher than you can get from either the Model 1 or the Apple IIc.
See specs: https://github.com/Tandy2K/Tandy2000/blob/mas … l%2026-5111.pdf.

[ WEB ] - [ BLOG ] - [ TUBE ] - [ CODE ]

Reply 2 of 5, by 90skidJohnny

User metadata
Rank Newbie
Rank
Newbie
VileR wrote on 2020-11-01, 17:47:

As far as I know it won't work with those machines. The Tandy 2000 outputs either 640x400 or 800x400 (depending on the adapter), so this monitor is designed for a 26.4KHz horizontal frequency, which is much higher than you can get from either the Model 1 or the Apple IIc.
See specs: https://github.com/Tandy2K/Tandy2000/blob/mas … l%2026-5111.pdf.

Most monitors work off a 15khz frequency right? Oof. Bummer. Second question, I think the tube is the same size that is in a TRS model 1 monitor. Would a tube swap work?

Reply 3 of 5, by VileR

User metadata
Rank Oldbie
Rank
Oldbie

Dunno about most, but for that time period probably yes, since most of those machines like the Model 1 and Apple IIc were designed for TV scan rates anyway.

No idea about a tube swap - I'd expect that most of the difference is actually in the electronics, not necessarily the tube itself. But it'd be a shame to take something relatively rare like a hi-res Tandy 2000 monitor (especially if it works!) and convert it into something that should be far more common anyway. 😉

Maybe some kind of scan converter/doubler is an option. Most modern ones won't support that target frequency, but maybe an oldschool one existed? Although it should be easier to source a lower-frequency monitor anyway.

[ WEB ] - [ BLOG ] - [ TUBE ] - [ CODE ]

Reply 4 of 5, by 90skidJohnny

User metadata
Rank Newbie
Rank
Newbie
VileR wrote on 2020-11-01, 20:12:

Dunno about most, but for that time period probably yes, since most of those machines like the Model 1 and Apple IIc were designed for TV scan rates anyway.

No idea about a tube swap - I'd expect that most of the difference is actually in the electronics, not necessarily the tube itself. But it'd be a shame to take something relatively rare like a hi-res Tandy 2000 monitor (especially if it works!) and convert it into something that should be far more common anyway. 😉

Maybe some kind of scan converter/doubler is an option. Most modern ones won't support that target frequency, but maybe an oldschool one existed? Although it should be easier to source a lower-frequency monitor anyway.

Yah I dont really want to tear it all apart. I bought it because of the aesthetics (its very 70s space age looking) and also, finding green phosphorus screens is , at least for me, very difficult. (or at the least, expensive)

I guess this one will go on my shelf for now, unless i stumble upon a tandy 2000 somewhere (altho I did find a tandy 1400 laptop here 🤣)

Thanks for the replies!

Reply 5 of 5, by Vynix

User metadata
Rank Member
Rank
Member

With monochrome tubes if they share the same socket, odds are that they are pin-compatible. Though you'll need to check the G1, G2 and heater voltages (and I am perhaps forgetting some parameters)

Proud owner of a Shuttle HOT-555A 430VX motherboard and two wonderful retro laptops, namely a Compaq Armada 1700 [nonfunctional] and a HP Omnibook XE3-GC [fully working :p]