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Worst case scenario plugging an LCD monitor (non-multisync) to Amiga 500

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Den2016

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I've got an Amiga 500 that I'd like to get going again. I've always used the A520 RF modulator to display to a TV set but I don't have one anymore.

So I've been reading online about hooking up the Amiga to an LCD computer monitor. I've read that a multisync monitor *should* work as they will run at 15 kHz from an RGB analog signal (re: http://15khz.wikidot.com/).

So all I need is an RGB to VGA adapter (passive) and a multisync monitor (please correct me if I'm wrong).

So to my question. I've got a few non-multisync monitors (LCD). If I plugged the Amiga to these monitors, will it actually destroy the monitors?

FYI, some of the datasheets that I read from some of the monitors listed in the above link (e.g. NEC) don't officially support a 15 kHz Hsync rate. So I'd like to save myself from having to try multiple multisync monitors in order to get one that works.

Hope someone can help.
Thanks.
 
No, at least not for the LCD monitors that I've used. At worst, you'll get an "Out of Range" message displayed.

CRT monitors, on the other hand, are a different matter.
 
I don't know if you will destroy the monitor, but it isn't a good idea. I'm not sure about the Amiga, but I know RGBI signals are TTL, 5 volts. VGA signals are 1 volt or less. I don't know if LCD monitors typically have over-voltage protection build in. There are some projects you can read about on this board that convert RGBI to analog RGB and then use a Gonbes 8200 or 8220 to convert to VGA. The Amiga might already be Analog RGB in which case you would only need the Gonbes unit or something similar. If you look around this board you will find various options.
 
Hi Chuck, KenEG,

So, I read online that the signals that I would want are the RGB analog signals (and not the RGBI signals). Apparently the digital signals only offer a limited number of colours compared to the analog signal. It's funny because none of the advice I see online about making a RGB to VGA adapter refers to voltage levels on the signals. So I'm assuming that the voltage levels coming out of the Amiga are 0 to 0.7 V (what's acceptable going into VGA).

I wish there was a resource (similar to the link above) which says, this Amiga, works with this adapter, works with this monitor. That way, we at least have something that says, this will work.

P.s. I just the manual for my HDTV and it has got composite video input. So I believe I can get RCA video cable and plug into the Amiga "mono(chrome)" and the composite video input on my TV. I can at least get some form of output from the computer.

Oh and another thing, is the Gonbes necessary?
 
If you find ANY LCD monitor that will sync up to the 15Khz you will have done better than I. I have a bunch of LCD monitors, and CRT types too, and NONE of them will sync to 15KHz. I know there are some that will do it, but it seems they are quite rare. I have never damaged anything trying it though.

This is what I use to connect standard monitors to my Amiga 500. It's better than the RF modulator, and cheaper, but not as good as a compatible monitor. You will need a DB23 female connector to hook up to the Amiga. Those can be had on eBay, but they are $$. I just sawed the last two pins off of a DB25 connector.

https://www.ebay.com/itm/Arcade-Gam...d=111780487964&_trksid=p2047675.c100011.m1850
 
LCDs intended as replacements for videogame and PLCs will do 15KHz very nicely, but are expensive as heck.

OTOH, there are LCD monitors that can get down to EGA frequencies.

Some of the older NEC professional LCD monitors may get down to 15KHz--I haven't checked the specs, however.
 
fatwizard said:
If you find ANY LCD monitor that will sync up to the 15Khz you will have done better than I. I have a bunch of LCD monitors, and CRT types too, and NONE of them will sync to 15KHz. I know there are some that will do it, but it seems they are quite rare. I have never damaged anything trying it though.

This is what I use to connect standard monitors to my Amiga 500. It's better than the RF modulator, and cheaper, but not as good as a compatible monitor. You will need a DB23 female connector to hook up to the Amiga. Those can be had on eBay, but they are $$. I just sawed the last two pins off of a DB25 connector.

https://www.ebay.com/itm/Arcade-Gam...d=111780487964&_trksid=p2047675.c100011.m1850
Click to expand...

That's a really nice option, and I may buy one for myself. I've got 3 Amiga computers, and I have to haul out my CRT everytime I want to hook them up. I'm always worried that one day my one monitor will just crap out.
 
I think your chances of finding an LCD monitor that will take a 15kHz signal is much more likely in Europe where many TVs included SCART connections that broke out the analog RGB signals. Here in North America there were very few systems that output this format.
 
Thanks everyone for all your responses.

The link efrestedt provided with the Google spreadsheet looks promising (as it confirms the list on 15khz.wikidots.com).
I should be able to locate one of those LCD TFT monitors on that list and give it a go.
 
You won't fry anything with a LCD. Most newer multisync CRTs will just go to standby mode when given a 15.75khz signal as well. That being said, I wasn't impressed with the quality of video from Samsung LCD's SCART RGB inputs. They appear to treat 240p video as 480i and needlessly de-interlace the incoming signal leading to blurriness and artifacts. Many of the cheapo RGB upscalers from ebay do the same thing.
 
I think it's becoming clearer to me.

The Amiga RGB analog signals are standard 0-0.7 V peak to peak signals but the CSYNC/HSYNC/VSYNC signals are digital (https://en.wikipedia.org/wiki/Amiga_video_connector) meaning 0-5 V signals. But looking at VGA, it's the same, http://martin.hinner.info/vga/pinout.html. So looking at http://www.retro-commodore.eu/2014/03/11/cheap-rgb-to-vga-converter-amiga/ if I use the CSYNC direct from the Amiga to the VGA monitor (that is multisync support 15 kHz hsync) then in theory it should work.

But that's in theory, so maybe it's interlace vs non-interlace that causes the problem? European users with SCART don't seem to have a problem. Perhaps it's the NTSC/PAL video output that is incongruous?

Anyway, I do have a Gonbes GBS-8220, and I've managed to chop a DB25 cable to fit the DB23 Amiga connector. I need a new multimeter to get the correct wires to the Gonbes. Once I confirm it works, I'll get a multisync LCD and try a cable direct from the A500 to the VGA monitor.
 
they show up on ebay from time to time. I have a NEC 19" 1970NX multisync. looks like there is a guy in canada with quite a few for on ebay for 50$. works fine on amiga with 15khz.

*emended my model number when I got home from work to 19" 1970NX, not 17" 1770NX*
 
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That confirmation is comforting. There is an NEC 1970NX available (online) but it's an hour+ drive. So I'm wonder if other NEC multisync monitors would work also? As I mentioned the spec sheets on these monitors do not indicate 15 kHz functionality. So I'm considering a 1560M (there is one available which is closer to me). I figure no one wants 15"/17" (and maybe 19") monitors anymore. So I can get them pretty cheap.
 
The best solution I have seen is a RGB to component video converter, then use a LCD TV that has a component (red, green, and blue RCA jacks) input as your monitor. If you don't already have the TV set then it may end up costing you as much as the other monitor options mentioned, though.
 
How about run of the mill LCD TVs ?
They come as small as 17", almost all have VGA input and by definition have to support NTSC signals (15750Hz horizontal).
Am I missing something here?
 
alpher said:
How about run of the mill LCD TVs ?
They come as small as 17", almost all have VGA input and by definition have to support NTSC signals (15750Hz horizontal).
Am I missing something here?
Click to expand...

Good luck with that. Every one of the TVs we own doesn't work at 15kHz when using the VGA input.
 
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