LCD with analog horizontal synch (15/24 kHz)

Started by kendrick, March 09, 2013, 03:45:37 AM

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So my workplace is disposing of old computing equipment, and it will cost them less for me to haul away a couple of old tube monitors than it would to pay the environmental disposal service to do it. I piped up because one of the monitors has lovely BNC connectors on the back and inputs for both separated synch and composite synch, which in my mind raises the chance of 15 kHz horizontal RGB to fifty-fifty. Sadly, I struck out because the monitor bottoms out at 30 kHz like every other VGA tube known to man.

It occurred to me that it's been quite a few years since anybody has asked the question. Is there, on the current market, a commercial-available screen that can handle the RGB horizontal synch frequencies we love from our game systems and arcade cabinets? I also recalled that there are now many retro arcade cabinets in the wild that use LCD screens, which are lighter and cheaper than CRTs but which are also likely connected to proprietary emulation systems not unlike PCs. So I did some searching.

Out in the Internet archives there's a dysfunctional Commodore Amiga discussion board where they explored exactly this topic and came up with a short list of candidates:

QuoteViewsonic VX2433WM 24 inch
Scan Frequency - 24 to 83KHz (Horizontal) x 50 to 76Hz (Vertical)


HP LE2201w 22 inch
Scan Frequency - 24 to 83KHz (Horizontal) x 50 to 76Hz (Vertical)


BenQ G2420HD 24 inch
Scan Frequency - 24 to 83KHz (Horizontal) x 50 to 76Hz (Vertical)


BenQ G2420HDB 24 inch
Scan Frequency - 20 to 83KHz (Horizontal) x 50 to 76Hz (Vertical)

None of these guys give you the magical 15 kHz horizontal synch, or if they do they only do so through a composite or component analog connection meant for TV input and not for RGB. But the fact that some of them can do 24 kHz reminds me that I have a disused Sega Model 2A arcade board sitting around that I've never found a screen for. I think I may have a new project.

Anyway, I start this thread for the purpose of inviting discussion about LCDs that can accept RGB input with the appropriate synch. Obviously talk about upscalers and other adapter equipment belongs in other threads for the most part, but I'm very interested to know if this is something anyone else is exploring at the moment.


Personal tests (marked by Src: me) based on 24KHz / 15 KHz output of Gradius IV PCB.

Dell U2211H (probably also U2311H) (eIPS) - works perfect, but note that the newer models e.g. U2312HM do not work - blank screen. Src: me
Dell 2209WA (eIPS) - works partially - vertical portion of the screen is cutoff but still playable - I don't have this LCD anymore. 15KHz out of range. Src: me
NEC EA231WMI (eIPS) - not sure if it's exactly this model, but I confirmed that a rotatable NEC IPS monitor worked with 24KHz, although I had to plug/unplug a few times before it detected the signal. Src: me
Mitsubishi RDT234WX (IPS) - works perfect, but this model is Japanese market only. 15KHz is out of range. Src: me

15KHz & 24KHz:
HYUNDAI W240D (TN) and W241DG (IPS). Some signals needed to be transcoded to component and fed into the D-terminal input. Src:
Mitsubishi MDT242WG (A-MVA). Tested SNES, Saturn, PS1 Src:
Mitsubishi MDT243WG (A-MVA). Tested SNES, Saturn, X1, PC9801(24KHz), X68k, but Megadrive v1 out of range. Src:

I believe there are a few BenQ and Dell models that do 15KHz but are TN monitors.


So unconfirmed, but I've read that a few holdouts have been using a specific ASUS model for Virtua Fighter 2 arcade rigs, which is exactly my use case. To whit:

Asus VS247 24 inch, 24 kHz

No idea if that's true, but it might be worth a hundred bucks for me to test. Maybe.