Eizo LCD monitor almost displays 15 kHz analog RGB video

[vwestlife]

Missed it by that much...

When connected to my Apple IIGS's 15 kHz analog RGB output using a Macintosh-to-VGA plug adapter, my Eizo FlexScan L771 LCD monitor complains "Signal Error" and shuts off after a few seconds, but if you turn it on again it will stay on and show a shrunken image in the middle of the screen, horizontally stretched and with the right side of the image cut off, but otherwise viewable.

The Eizo L771 has a 19.6" 1600x1200 panel and a rated scan range of 27 to 94 kHz horizontal and 50 to 85 Hz vertical.

 

[olePigeon]

That's a fancy LCD panel, I'm very surprised you got anything on it at all! If I remember correctly, the IIgs's RGB port is not a standard analog signal. Might even be digital, more akin to CGA. Also, the signaling on the pins is different, and it won't work with a standard Macintosh to VGA adapter.

I had to buy one of these (unfortunately he's all out):

http://www.ebay.com/itm/Apple-IIGS-Video-Adapter-for-the-GBS-8200-8220-Video-Converter-/131580376282

... which does the conversion for you. I use it with the CGA to VGA adapter board he lists it as compatible. For my IIgs, it works pretty well hooked up to the VGA display.

I wonder if your LCD is fancy enough to also accept CGA signals like a true MultiSync.

 

[vwestlife]

The IIGS does produce 15.7 kHz analog RGB video. It couldn't be digital (TTL), or else it wouldn't support the IIGS's full 4096-color palette. It does use composite sync, but older Macs provide composite sync as well as separate H/V sync:

Apple IIGS RGB pinout:
pin # signal
1 ground (for red)
2 red
3 composite sync
4 not used
5 green
6 ground (for green)
7 -5 V
8 +12 V
9 blue
10 not used
11 audio output (not used)
12 monochrome screen off (?)
13 ground (for blue)
14 not used
15 not used

Mac video pinout:
Pin Function
1 Red Video GND
2 Red Video
3 Composite Sync
4 Mon. ID 1
5 Green Video
6 Green Video GND
7 Mon. ID 2
8 N.C.
9 Blue Video
10 Mon. ID 3
11 CSync and VSync GND
12 VSync
13 Blue Video GND
14 HSync GND
15 HSync

 

[olePigeon]

Ah, OK. You obviously know more about it than I do. Just judging from my own experience. I couldn't get the adapter to work with my CGA board, so I had get that other one. Maybe it's unique to the CGA board.

 

[olePigeon]

Still a nice display, though. Hard to find cheap 1600x1200 displays nowadays, everything's widescreen. Bah!

 

[Chuck(G)]

They're around on eBay. Sitting in front of NEC model right now. Cost about $70 shipped.

 

[vwestlife]

The Eizo cost me $11 at a thrift store, as compared to its list price of $5500 when new.

It's great for classic PCs and Macs at 800x600 resolution, because that's exactly half of the panel resolution, so there's no scaling artifacts; it just doubles the pixels.

 

[olePigeon]

I'm scared to death of buying a used one on eBay. I've bought 2 1600x1200 LCDs with promises of no dead-pixels, and both had 3 or 4 dead pixels.

 

[njroadfan]

Many 1920x1200 LCD displays have no problem showing 1600x1200 content without scaling.