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Re: Old CGA monochrome monitor color fidelity

in Marvin \ Video
Many of the turbo XT clones had graphics adapters that did both MDA and CGA modes, and were equipped with monochrome displays that could switch between the MDA and CGA frequencies, so you'd get a nice crisp MDA style text mode at the DOS prompt and normal CGA graphics (320x200 with 4 levels of mono …

Re: Old CGA monochrome monitor color fidelity

in Marvin \ Video
Here's one of the few photos I have left of my monitor, albeit without a color test that shows any other shades unfortunately. That photo clearly shows an MDA/Hercules text mode (9x14 font) so I'm guessing that you had a Hercules (or compatible) mono card and used a TSR such as SIMCGA. You get two …

Re: CRT nostalgia vs the 15KHz monitor whine

in Milliways
Back when CRT televisions were still common, I could usually hear the 15.7khz whine even from another room. But most people couldn't hear it, even when I'd specifically point it out. (I can't hear the 18.4khz from a monochrome display, though.) And once a CRT is up and running, the whine will fade …

Re: EGA DOS benchmarks?

in Marvin \ Video
So far the only objective benchmarks suggested are the video tests from Check It and Landmark, which seem oriented towards text mode performance. Any others out there? I don't think EGA 4bpp has to be any slower than CGA 2bpp, because one of the big features of EGA graphics is the capability to …

Re: IBM 5151 on modern PC

in Marvin \ Video
As far as destroying the horizontal output transistor goes, my impression is that *running the sync frequency too low* is what kills it. The lower frequency results in the H.O.T. being switched on for too long. Once the horizontal yoke and tuning inductors become fully saturated they essentially …

Re: Why amstrad pc1640 won't boot?

Amstrad drive ID etc is set up more like Shugart standard than IBM's perverted version of standard, so while Amstrad drives can be got to work with IBM PC interfaces, it's gonna confuse the hell out of our friend here. Take cellphone pics of the jumpers before you start messing around. I think …

Re: Why amstrad pc1640 won't boot?

If the floppy drives and media have been in storage for a while (sounds likely) you'll probably need to clean the magnetic heads in the drives and also clean the surface of the magnetic media inside the floppies. You may also need to clean and then lubricate the metal rails inside the drives; this …

Re: Quandchrome EGA screen failure.

in Marvin \ Video
SVD wrote on 2021-11-29, 19:19: Since none of the TV-repair shops around answers my call, I really hope someone can help me with this You can also try posting at the VCF forums (vcfed.org) - there are a couple of members over there with a lot of CRT troubleshooting experience. (I'm thinking of Hugo …

Re: Quandchrome EGA screen failure.

in Marvin \ Video
It's quite common for monitors of that era. A usual quick test for monitors in the 80s was to disconnect the input and turn up the brightness to 80%. You expected a light gray screen with small black borders left and right. The black borders in the OP are too wide, so the picture is suspect. The …

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