On the CGA/EGA color palette issue: For a good while, I had to use a (clone) CGA monitor with a (Genoa) EGA [and later multiple VGA] card and learned a lot from this experience. The CGA monitor could accept any color on its analog inputs. Yet I could only see 8 colors (not even 16!) with the EGA card attached and the reason, as I learned it, that EGA sent 2-bit digital color information per channel instead of the 1-pin CGA outputs. I soldered a little homebrew DAC for the EGA outputs and it was solved, the CGA monitor could display all the 64 colors the EGA card output. Then I went further and could display 256 colors with a Tseng ET3000 EGA/VGA card through a 15->9-pin D-SUB converter. I had to deal with the increased text resolution, though as 400 lines at 70Hz was something the CGA monitor couldn't deal with at all. But setting EGA-200 timings and other VGA registers set it right again. The pinnacle was 64k colors with an S3 Trio64V+ but that needed serious BIOS debug and then a TSR to reprogram everything after a mode switch (my textmode was intelaced, crazy eh?) but for me it was worth it (as I just couldn't afford a VGA monitor). Of course it couldn't deal with any program that changed the VGA registers for different resolutions, anything non-standard was impossible to see.
@@ropersonline Oh no, that was no 5153 of course. It was some RGB thing I got for my Videoton TVC, proper CGA resolution and couldn't get reverse priority sync signals or something similar happened when I attached it to a PC - but the Tseng ET3000 had registers for sync polarity after all... and the S3 too.... And interlaced 640x480 was kind of twisted :P
Hardware designer: Let's design a card capable of more colors than CGA. We'll make it capable of displaying 16 colors at once, out of a palette of 64. But let's make it compatible with existing CGA monitors, so that virtually nobody will ever use any of the colors other than the default 16.
Not only are those EGA cards rare as hen's teeth but EGA monitors are as well... If we only knew 20-25 years ago that those parts we took the dump would be "retro" and worth cash these days.
Indeed. I think another thing that contributed to their rarity today is the fact prices on EGA cards and monitors never dropped very much before VGA was introduced. As I remember, there were only a few non-IBM EGA cards available, Paradise and ATI among them. I want to say there was something about the analog VGA signal that made VGA monitors and cards cheaper to build than EGA, or at least that allowed an economy of scale to develop much more quickly. VGA prices started to drop very soon after it was introduced, dozens of card makers came to the market and so competition was much greater. Not only that, but you must remember that CGA cards could be used with any standard color TV that featured a composite input connector. EGA cards could not do that, so even though CGA cards were expensive during their day, more people were willing to buy one since they could use it with the color TV they probably already owned. EGA monitor prices were always high, and so people just waited for a better alternative. With VGA, the improvement was so dramatic over both CGA and EGA that, as prices dropped, many many more people wanted it much more than they had ever wanted EGA.
The cards are rare but not immensly rare. The monitors are though. I managed to scrape 3 of these cards (a Vtech, an ATI and a Paradise) together in 2 years for my collection but only one real (Tulip) EGA monitor :-) Always liked the weird way text appears on these things. You can tell immediately that it's EGA because of the weird "compressed" look (like exactly in between CGA and VGA fonts quality wise) ;-)
I wonder who is buying these EGA cards today, when you can buy a VGA card that is compatible to CGA and EGA and allows to connect modern displays with VGA to HDMI adapters.
@@OpenGL4ever Gaming purists - you can DOSBOX emulate anything even without hardware but realistically some people will want to run a game on original hardware as it originally ran.
@@djrmarketing598 VGA is fully compatible to EGA. For real hardware you would rather buy a VGA card. I can understand people who buy a CGA card more. Because that would at least give you a brown color, which would be yellow on an EGA or VGA card, which can be a problem if you want to be as close as possible to the real thing. But for EGA vs. VGA, there is no such thing. VGA fully replaces EGA.
2:36: Those two RCA connectors on the EGA were rarely explained or understood, but thanks to some info on minuszerodegrees, I now know that the RCA jack closest to the DE-9 connector would have been composite input, which got routed through to the internal (brown) feature connector at the top, and then the composite output from whatever was plugged into that feature connector would have been routed to the other RCA jack as output. Apparently the plan was that the EGA plus an optional add-on card plugged into that feature connector would jointly produce output, perhaps to overlay EGA graphics onto whatever the composite input was, perhaps as a character generator, on which see Wikipedia. HOWEVER: I have never ever heard of, never mind seen any such an add-on card actually in existence. Maybe none was ever made, despite the fact that IBM's and many clone-maker's EGA cards had the "plumbing" in place. Absent any such add-on, those RCA jacks would have remained completely useless, as the EGA cannot deal with them on its own, and unlike the CGA's composite out, the EGA also produces no composite output there on its own. I don't think even EGA clone cards did that either. It really was just like unused plumbing: It came with the card but was left to lie idle.
Great detective work! Thanks for the info. I had the feeling they were probably useless, although one wonders if there may have been technology used in TV broadcast stations that made use of it somehow.
@@PCRetroTech That's where that would have made sense, but I've never even heard of any actually existing. Maybe IBM expected others to make these, but EGA wasn't successful enough for that. Yes, as a software standard, but I reckon far fewer EGA cards were sold than VGA or even CGA cards. How hard would it be to build an EGA feature connector-compatible (character generator, etc.) add-on today, I wonder? Bit of retro-tech? (Though above my pay grade.)
Those RCA jacks on the original IBM EGA card are both directly connected to the feature connector but I don't know of any uses for it. Someone once mentioned you could hook up a lightpen module to it. I don't really know for sure.. My rare Vtech 256k EGA clone card, which is an interesting card really, has two RCA jacks as well and they actually both work to my surprise as, like you mentioned, on most cards they were unused by default. One is apparantly for color and the other for monochrome. But as I live in a PAL region it's monochrome on both outputs (one should display color CGA and the other hercules if I change the dip switches correspondingly). I wonder what happens if I hook up my PVM that supports NTSC color burst and if it will actually display composite color on the Laser Turbo XT, which runs at 10MHz as this card was specifically built for this machine by Vtech.. I only managed to do get composite color out of an IBM 5150 with the original i8088 CPU @ 4.77MHz and it looks excellent on my PVM, especially 8088MPH and the recently released composite versions Commander Keen look really cool. When I changed the CPU to an NEC V20: no color, even at 4.77MHz (must have something to do with the V20 being more efficient and requiring less CPU cycles than the i8088 to complete similar tasks). When I added my home made turbo board with an i8088-2 or a V20 at 6.66MHz: no color. I could turn the colorburst trimpot on the planar all I wanted: It seems that the only way to get the NTSC colorburst right is an i8088 @ 4.77. I guess the colorburst's timing is really sensitive and it's apparantly very easy to put the chroma signal out of phase making it B&W or really ugly looking :-) I might have more success using a different trimpot or adding a resistor but that would require some scoping ;-) The other (super) EGA clone cards I own, the ATI VIP, which is a really rare early attempt by ATI to build an EGA/"partial" VGA card and the Tulip TEVA, which is a rebranded Paradise card do not have RCA jacks.. All three have 256k DRAM on board.
I just tested the Vtech EGA card I mentioned in my previous post and it does display EGA graphics over composite on the 10MHz Laser Turbo XT! Wow, first time I've seen this :-) I was going to sell the entire machine but I'm hanging on to this card now :-)
I actually use an ET4000 card in my 5150 since I have no CRT monitors. It has excellent CGA/EGA support. I think it will even do Hercules monochrome but I haven't tried it.
i had an ega display, which could be switched to hercules mode. i counted the pixels in x and y in deluxe paint, and it was 720x348, no less. the game electro body ran faster in hercules so i played it in monochrome :) there were a lot of games that looked beautiful even in 16 colours. simcity, the goblins series, warlords 1, street rod 1-2, duke nukem 1 etc. i very fondly remember those years.
As a kid I had an nec powermate iv 286 with a non IBM EGA card (i cannot remember the brand but it was very cheap) and an IBM CGA screen (similar to the model you had when running the test). I could run in ega low and standard but not hi-res. Spent hours playing stunts, lakers vs celtics, leaderboard golf and catacomb abyss just to name a few :-) Man I wish I could get that screen back, it was very sharp as you say.
So far I've looked at two of the IBM 5153 CGA monitors, and they are both very sharp. Of course you can always get a dodgy one, but maybe it's not so hard to get a good crisp one. But they are expensive though, sadly, and depending where you live, maybe even hard to find nearby.
Hi - at work we hard our first PC's NEC Powermate IV - 4 286 based, they all had the base setup but the line manager complained that for @ $ 4,000 AU people should not complaint about bad screens and headaches So they replaced all the CGA screens and video cards with NEC's special EGA Enhansed cards and the NEC Multisync monitor - they were beautiful We ended up getting friendly with one of the NEC support techs, later they came out and updated 2 of the 6 machines ( shared between 90 people ) from 2 x 5.25 floppy and removed one of the floppy and added 20 meg hard drives As i was running CGA at home at the time, he gave me some advice on what to buy and upgrade and a shareware program called CompuShow - abbreviated as cshow, this is just a graphics viewing program but you could alter between card and screen resolutions, you could also save same files as other formats - it all fit on a single floppy - he gave me a copy plus some utils to test monitor resolutions colours etc - but that was back in ??1986-1988 Like most people i loved my EGA - i had a generic brand screen that came with my PC AT - but ended up buying a used multisync monitor - it was slightly different to the ones at work - at work they had a control panel on the top of the monitor like a small trap door - i think power and brightness / contrast was on the bezel but other adjustments were under this trap door - the one i purchased this one was either made the same year or a year later and had the controls on the base of the bezel - like the typical VGA monitors For some reason i recall the video cables were unique to the multisync - maybe just the spare were labeled so we dont confuse them with anything else ?? Regards George
I wish I knew how to fix my EGA monitor because it supports all pre-vga signals and even high res EGA, so it probably supports 64 color EGA too. Unfortunately the CRT displays colors brighter on the left compared to the right for some reasons ...
That limitation only exists in monitors. It's easy to find resources on the web that will tell you how to switch to EGA 320x200 with a choice of 64 colours (in a palette of 16 colours). IBM officially only supported the 16 CGA colours in all the 200 line modes, but even that card actually supported all 64 in practice.
are there any cards that support both EGA and VGA monitors? just for kicks... ega monitor i used to have had some nice scan lines, but bumping up to vga, no more scan lines.
There are passive adapters. I dont knpw quite how the worked. But back in my highschool there was loads of ega monitors driven by vga cards via passive adapters. Woked just fine, could even go 640x480... but was fairly low freqvency
Huh, that monitor at 13:00 in is an IBM 5153? Is it possible that maybe it's a 5154 that was rebadged as a 5153/CGA monitor as a later cost-reduction thing? Because as far as I know the original 5153 wasn't even physically capable of doing anything other than 4-bit RGBI.
It's definitely possible I guess. It is an American monitor. That's about the only thing I can say about it. It doesn't support dual supply, which probably means it is a little early. Even so, it doesn't have phosphors for 350 lines, so it's not a 5154 in resolution. It might have 5154 electronics though, who knows.
Yeah, seeing a nice non-RGBI palette on a 5153 really surprised me too. And I don't think it is a rebadged 5154 monitor, because it was unable to sync on the 640x350 mode.
@@asgerms Huh, interesting. I'd be really tempted to see what happens if the various intensity pins' connections are interrupted (maybe by making a DB9 passthrough cable that goes through jumpers on a breadboard or something).
@@fluffycritter I suspect the video card "has tricks", because even on EGA systems the 16-color 320x200 modes are RGBI only (64-color palette only available in 640x350). I had an ATI EGA Wonder 800 back in the day, and it "had tricks" making it almost VGA. So I just downloaded the manual for 800+, and it lists the capabilities for ega monitors, multisync monitors, cga monitors, mono, etc. Under capabilities for CGA monitors it says "ATI proprietary technique maintains a palette of 64 colors for CGA and EGA software". What that technique is, or if he is actually using that card, I don't know. Should be interesting to see if they are PWM'ing the RGBI or something.
@@asgerms Yeah, I'm just wondering if it would still work after disabling the alternate intensity bits. It's possible the video card is just, like, very rapidly dithering the colors to simulate 6-bit colors on RGBI or something. Or maybe some versions of the 5153 actually did support the intensity bits and it just wasn't advertised.
That sounds like it isn't selecting the palette correctly. That's odd because the EGA of the Amstrad is just a fairly standard chip. Or are you using an Amstrad PC1512, which would be CGA?
@@PCRetroTech no, only via 86box/DOSbox-X. Once I can fix my Amiga 2000 and get the A2286 bridgeboard someone I know is selling, I can test with my ATI VGA Wonder XL/24 set to EGA (via the 9-pin instead of the VGA out), and via an RGB2HDMI.
@@NightSprinter I don't know how well VGA cards really get the colours of EGA though. In theory they should be the same, but I don't know if that's always the experience.
Yes, I found the problem. It wasn't the EGA card at all. The memory expansion card in my computer was misconfigured. Once I corrected that, everything worked without any issues. I don't know why I was only seeing it with this one EGA card, but I was very relieved when I figured out the memory expansion card was definitely misconfigured and also causing the problem. The original owner of the machine probably put up with that for nearly 40 years!
@@PCRetroTech Wow. My computer is a IBM XT286 from 1987 with 640kB of RAM. CGA modes always work, EGA modes do not. I don't have a memory expansion card. The problem looks so similar to yours. :-(
EGA had two resolutions in the vertical direction (known as Mode 1 and Mode 2 EGA). Only mode 1 EGA (with 200 scanlines in the active region) is going to be compatible with a CGA monitor. Also, EGA has a palette of 64 colours (16 of which can be seen at a time). True EGA monitors have extra pins for the extra levels of intensity. However, I have connected my EGA card to my IBM CGA monitor and it worked just fine. So long as you stay in resolutions supported by that monitor and don't expect too much from it, there's a good chance it will work, albeit with the colours not looking correct. Get ready to switch your monitor off immediately if it looks to be losing sync. Some monitors seem to be very sensitive and can be damaged if you try to put them into modes they don't support.
@@pauloalba3298 The original IBM EGA card could actually be configured to use their IBM 5153 CGA monitor in fact. Technically the intensity pin on CGA gets used for just one colour intensity on EGA and the other two pins used for EGA intensity levels are not connected on CGA. There are other complications, but this is the long and short of it.
