konc wrote:

Just because you haven't done something and you don't trust others, doesn't automatically make it a mystery waiting to be solved. Others have. I get it that you want to see for yourself though.

It's a mistery to me and many others. Like claiming that the 5151 gets damaged using a CGA signal but not providing photo evidence. Some believe it, I don't. And it brings me back to my original claim that it's a widely spread urban legend, nothing more. It's either right or wrong, 50-50 until somebody comes out with photo proof.

Miphee wrote:

It's a mistery to me and many others. Like claiming that the 5151 gets damaged using a CGA signal but not providing photo evidence. Some believe it, I don't. And it brings me back to my original claim that it's a widely spread urban legend, nothing more. It's either right or wrong, 50-50 until somebody comes out with photo proof.

Photo evidence perhaps not, but it is documented:
http://minuszerodegrees.net/5151/problems/515 … lems_issues.htm
http://minuszerodegrees.net/manuals/AST/Bulle … AST_TB_0245.TXT

If it's an urban legend, it's a very long running urban legend.

I've just found an article I've read back in the era - in the January 1990 issue of "Młody Technik", on how to adapt certain TV-like (15 kHz HSYNC) monitor for usage with Hercules Graphics Card.
And the article mentions why such an adaptation may come in handy: because Hercules monitors are susceptible to damage due to improper programming of MC 6845.

Nowadays, if a 30 years old monitor fails, it may mean nothing.
But, if such monitors used to fail even brand-new, then very likely there's something to it.

Grzyb wrote:

If it's an urban legend, it's a very long running urban legend. […]
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If it's an urban legend, it's a very long running urban legend.

I've just found an article I've read back in the era - in the January 1990 issue of "Młody Technik", on how to adapt certain TV-like (15 kHz HSYNC) monitor for usage with Hercules Graphics Card.
And the article mentions why such an adaptation may come in handy: because Hercules monitors are susceptible to damage due to improper programming of MC 6845.

Nowadays, if a 30 years old monitor fails, it may mean nothing.
But, if such monitors used to fail even brand-new, then very likely there's something to it.

Well, yes and no... Yes - because if it fails in hands of some hobbyst, then he will probably take another one off his shelf and that's all. No because there is still plenty of old Hercules/MDA, CGA and EGA monitors used on old production lines, machine tools, diagnostic stations and so on. From time to time I see some posts of people who look for certain monitors (or just CRTs for monitors) stating that 'price is not an issue' - because display failed and production is on hold. There are dedicated LCD displays available but usually prices are ridiculous. Of course nobody will experiment with hooking production line displays into some random incompatible graphic card just to 'test something' - but it still such failure can cause a lot of trouble 😉

This might be relevant here as well: 2 (older) YouTube videos of games running on an ATI VGA Wonder+ hooked up to an IBM 5151 monochrome monitor, with 16-color emulation in 320x200 graphics mode. Apparently it also utilizes not only dithering, but also the 2 pixel intensity levels on MDA/Hercules monitors to pull that off. (Hercules cards supported 2 intensity levels only in text mode.) http://www.vcfed.org/forum/showthread.php?269 … 3389#post193389

Scali wrote on 2019-10-20, 17:02:

Photo evidence perhaps not, but it is documented: http://minuszerodegrees.net/5151/problems/515 … lems_issues.htm http://minusze […]
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Miphee wrote:

It's a mistery to me and many others. Like claiming that the 5151 gets damaged using a CGA signal but not providing photo evidence. Some believe it, I don't. And it brings me back to my original claim that it's a widely spread urban legend, nothing more. It's either right or wrong, 50-50 until somebody comes out with photo proof.

Photo evidence perhaps not, but it is documented:
http://minuszerodegrees.net/5151/problems/515 … lems_issues.htm
http://minuszerodegrees.net/manuals/AST/Bulle … AST_TB_0245.TXT

It is worth noting that sometimes a monitor with a pin labeled NC actually goes to ground so if you randomly hook up things you may blow up stuff feeding voltage where it doesn’t belong.

If you want to make a
WHA HAPUN ? Video about attaching CGA TO MDA at a minimum make sure you adapt your hookup so the NCs stay that way and the video signaling pins are in the right spots.

If you do record this
do it with the case off,
low lighting so we can see the fly back

WHA HAPUN?

Then do a diagnostic and repair if needed.