VOGONS


First post, by Sseleman

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Hello

I have this not so little monitor for a week. And trying to get "static" picture on it with no luck.

It has R G B and Ext. sync BNC slots on the back. So, I tried direct EGA-RGB (hsync-ext.sync) and it shows only the (top down) scrolling text instead of the static.

Next, ive tried VGA(Trident 9000)+Kramer VP103 converter, that could produce csync and sync on green from VGA. Just to get the same scrolling picture in both modes.

I even tried the different modes that my Trident card can switch on int 13h. And still no luck. Text is absolutely sharp. But scrolling (either top down or bottom to top) rather than being static, as I used to watch.

If you have some documentation on its res and freq or have some experience dealing with such monitors, could you please give me the advice or maybe some directions to make it show the good old not scrolling picture?

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Reply 1 of 13, by rmay635703

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That’s a fixed frequency screen, some were setup for Amiga/broadcast video equipment, others were hooked to medical stuff.

I would recommend trying something that runs 15khz or pal/scart using the ext sync for RGB+Sync.

Despite the size and cost it’s unlikely that it’s configured for Sun equipment (ADI in that era made oddball proprietary stuff for Sun, Apple and broadcast applications)

What’s sad is that 10+ years ago you could easily find these screens on Google, all the good data seems to be long gone.

Reply 2 of 13, by Sseleman

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15KHz

I already tried this by connecting EGA-RGB. Tester in all modes that my Dega card is capable. Hsync and vsync connected to the ext.sync produced the same scrolling. Either connected directly or via csync maded by the couple of resistors and one transistor (scheme with AND logic).

Something strange static was happened once when I connected CGA hsync to the green. Ill give the second chance to this. Thanks for pointing me to the single freq monitors.

Reply 3 of 13, by BitWrangler

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So you're just giving it horizontal sync, no vertical, and wondering why it's rolling? You are going to need to rig a sync combiner.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 6 of 13, by rmay635703

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BitWrangler wrote on 2024-10-30, 19:03:

So you're just giving it horizontal sync, no vertical, and wondering why it's rolling? You are going to need to rig a sync combiner.

Would like this comment if I could.

Screen at a minimum needs combined sync and it’s possible sync on green is required with proper termination and ohms if it’s an oddball .

We then get into the different types of sync,
hi-z, sync polarity and other goodies that need to also match up.

A simple question have you literally tried just attaching an rca composite video cable to green? (Like is found on a video game, vcr or dvd player)

I have a bunch of cheap adapters and if that works you know the answer, given ADI didn’t really sell screens under it’s label in North America until at least 1993, that thing could literally be anything even pal (depending on region) as they had security and pos/terminal markets back then also.

If it were my screen I would post photos front and back along with any knobs, buttons and switches then tear the cover off to see if anything inside is “common/standard” with another screen manufacturer. Photos of the video board might help also. (Shouldn’t need saying but high voltage is in there even when the screen is off)

The photo you have is very poor, the chassis looks very similar to one of the deep boxy screens I used to have (not AIC but 1990 era) but my set had a different back panel on the upper right and without a side and front view I couldn’t tell you if there is a lookalike monitor we could also search for.

You may find unused circuit board sections inside the screens video input board that you could populate to be more useful. If s also possible that the internal circuit boards are labeled well enough to spell out the type of video or system(s) it was meant to work with. You can sometimes reverse engineer the scan rate looking inside.

Sseleman wrote on 2024-10-30, 19:26:

As a rule, by adding Vsync I always got no picture at all.

Ok. My plan for now is to make dsub9F to dsub15M "converter" and then route the singnals from CGA card to my Kramer converter.

You do know for testing that you can just disconnect green and attach the v sync to the green BNC and attach h-sync to external (on many of these screens). Considering the proprietary nature though the screen may be very picky about TTL/analog and 75ohm termination, gotta open it up to figure out what they did because some screens are very picky about the sync signal.

Also worth saying, although rare you can damage a screen by sending the wrong form of signal TTL vrs analog and extreme desyncing can potentially cause damage.

Reply 7 of 13, by Sseleman

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Ok. Thank for reply. Luckly it still not damaged yet.

Ready to provide some photo of internals.

I want to test this v-hold adjustable resistor, that is locked now.

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Reply 8 of 13, by rmay635703

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If that works for vga good for you, if it’s one of the 66hz refresh rate fixed frequency screens for sun/mac you might be able to tweak it enough to use for a vga/svga mode.

That sparse board reminds me more of 1987 than 1990 but whatever, simple components, I don’t see the junction board, are the BNC connections soldered directly to the board or are they floating wires?

Reply 9 of 13, by Sseleman

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Right now Iam having deep dive into old reviews of struggles with fixed freq monitors. Like:
https://web.archive.org/web/19970706005627/ht … hitachi.html#os
https://www.repairfaq.org/sam/monfaq.htm#monlhsaw

So I can conclude that V-Hold is probably what I need. And maybe Win95 or Linux with unusual res and freq settings and some newer videocard.

Reply 10 of 13, by Sseleman

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rmay635703 wrote on 2024-10-30, 22:44:

I don’t see the junction board, are the BNC connections soldered directly to the board or are they floating wires?

All that related to R G B singnals are on the separate board. With the 2 adjustable resistor on each line. But the colors are seems to be right, so I dont have plans to touch this board at all.

Reply 11 of 13, by rmay635703

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Sseleman wrote on 2024-10-30, 23:02:
rmay635703 wrote on 2024-10-30, 22:44:

I don’t see the junction board, are the BNC connections soldered directly to the board or are they floating wires?

All that related to R G B singnals are on the separate board. With the 2 adjustable resistor on each line. But the colors are seems to be right, so I dont have plans to touch this board at all.

Yeah the color balance doesn’t concern me but the presence of pots on each color indicates analog signaling (not TTL), occasionally you can find the components generating separate sync there which is useful if it’s simple enough to hack in separate sync compatibility.

Anyway So long as the intended video input is analog signaling like vga , terminated and doesn’t expect anything strange it’s good.

I would strongly recommend finding something akin to h-sync or h-hold, you can relocate the pots outside the screen allowing you to attempt to sync in to various resolutions

Reply 12 of 13, by Sseleman

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Its finally working in Windows XP with the standart resolution 1280x1024 at 60Hz

Below are the photos of resistors positions, Windows cmd in fullscreen and artifacts in gui mode.

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Reply 13 of 13, by Sseleman

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Yeah the color balance doesn’t concern me but the presence of pots on each color indicates analog signaling (not TTL), occasionally you can find the components generating separate sync there which is useful if it’s simple enough to hack in separate sync compatibility.

OMG i didnt get this in to account. This time I was simply lucky.

I would strongly recommend finding something akin to h-sync or h-hold, you can relocate the pots outside the screen allowing you to attempt to sync in to various resolutions

Hm good point. Thanks.