Updates of my MCE-Adapter (simpe MDA, CGA, EGA converter) 

Ah the times where devs were literally hacking display hardware to apply new tricks and enhance their game's gfx :) nowadays it's more software-first and backwards in a way. That's an awesome adapter making life easier for anyone wanting their nostalgia on true retro hardware though! Thank you for making it!

This is such a nifty little project! 😃 As the picky engineer that I am, I have a remark on the way you generated a logic signal out of the sync pulse: I would be a little more careful about placing an "analog" signal onto a CMOS input. When the sync pulse changes between positive and negative polarity, the low-pass filtered signal transitions accordingly and therefore spends a relatively long time between High and Low logic levels. In this conditions a CMOS input does not guarantee that either the top MOSFET or the bottom MOSFET are completely off so there is the chance that some current flows directly between VCC and GND. This stresses the input and can, potentially lead to failure. A second problem is that, while the filtered signal crosses the threshold, it doesn't do it "decisively" so even little noise can cause spurious transitions which can be a problem for asynchronous logic. In your case transitions are fairly rare so, probably, nothing bad happens but there is a simple way to make sure that everything is fine: insert a logic gate (either a NOT or a buffer) between the RC filter and the input of the GAL. Make sure to choose a logic gate with Schmitt-trigger input (which has hysteresis so different thresholds depending on the state of its output), with supply voltage suitable for the input of the GAL and with input logic levels suitable for the sync signal. Such single gates are available in quite small packages.

Clever. Nice refinement. Can't wait for the next OC video.

Great job on the update.. thanks for sharing.

Thank you that you listened to my request for amber color.

Thanks for the new version. Your contributions are priceless !!!

Fantastic job sir!

Very clever, lovely job!

Hey 2 years ago you did a video on the Pro Audio Spectrum and at the end hinted at doing a video about the Aureal Vortex chips. I know it's been a long time but would you still consider doing it? I loved my Vortex 2 back in the day and your Pro Audio Spectrum video had a lot of interesting information I wasn't aware of.

Very cool and so many good improvements.🙂 In hindsight it is funny the EGA engineers didn't just do brown instead by default as slightly darker yellow doesn't have many contextual uses. Other major change I'd have made is making Cyan & Dark Cyan darker too as they have too little contrast with White & Grey. But then again in hindsight I'd have made CGA's second brightest shade also darker since it is not contrasted enough with the brightest shade Ie. see Game Boy gradient contrast. I really love the Hercules color tint option as any options are better than none, Green looked great but a shame Amber couldn't be better. That's been something I've speculated on like changing monochrome graphics to color tints on color screens or putting a color gel layer over a B&W CRT to give it a similar look to monochrome phosphor tints since they aren't as plentiful.

Great job! Thank you very much! Will try to make one to connect pair my Toshiba laptops to the external monitor!

Always a great video

If at any point you consider producing these devices for sale, I'd love to buy one for my EGA 286 project that I have planned.

Very nice! Only thing I would suggest is to add a buffer to drive the analog signals with the proper 75 ohm impedance.

This is pretty cool.

Neatly done! Content like this is what keeps me watching.

Great job

Wow cool project

I should get one of these and test out my 20+ LCDs in my basement to see which ones will work with MDA/CGA/EGA

loving the new features! dunno how you squeezed all that into a GAL...

Imma call it “banana mode”

Okay, I do have to wonder if the early-revision MDA colour-output undocumented feature works on this. If you haven't heard of it, the attribute bits on MDA match up with colour bits on CGA text mode, giving underlined text on MDA and blue text on CGA, but early MDA cards connect those bits to the pins used by the RGB channels on CGA (intensity is the same on both), so you can actually get colour out of them if you hook them up to a colour TTL monitor that'll take their sync signals. Also, the MDA output with the intensity should be giving you 4 colours, not 3: black, white, and two shades of grey. A darker shade of grey from 0 video and 1 intensity, and a lighter one from 1 for video and 0 for intensity.

Very interesting and useful so far. btw, it could be interesting and perhaps meanful if you would look at the floppy drives problems and howto for floppies. I've got the Samsung 3.5'' its lamp lights when the PC addresses to it and the large flywheel below (going opened to bottom side of it) doesn't rotate... suppose its drive engine burnt as far it was used as a test device lying on the table... So far, waiting for new videos gratefully.

How about making the adapter expansion slot mount now that it auto detects? Can then use a short ttl jumper like you would for a voodoo. You could then even use internal headers on some cards over to the adapter.

I have a GAL16V8D and I thinking on make one adapter latter on. is this GAL fully compatible? I also have some ATF22V10C PLDs. those are a little more complex/capable, useful to do some extra things in this converter. the thing I miss is to be able to run/upconvert to 30KHz so is easier to find compatible monitors

Awesome! Will this work with the RGBi signal of a Commodore128 as well? And can I assume the PCBWay shared project will be updated? (Would make it easy to get me one of those boards, or 10 as that costs the same ;) )

very cool new hardware! however, I kind of didn't understand the beginning of the video. It seemed like you were about to talk about the GBS, but then you never mentioned it again?

Hi! Which desoldering station you can recommend? What desoldering station on video "Repairathon 2022: Repairing a heavily damaged 386 mainboard", temperature?

I could use one of these for my Laser 128.

Very neat! I'd love to build a few of these and sell them if you'd be okay with that. =)

Would it be possible for me to wire an adapter cable to use this with an Apple IIGS like I already do with the cheap (re: crap) chinese conversion board or is it strictly designed for handling PC standards

Hello, I ordered the PCB's from PCBWay, they arrived today and the components must be soon, now I am stuck, cant figure it out the assembly instructions, where do I find the instructions?

i need to have a way to use MDA or CGA on a VGA CRT and that seems to be the solution

Some EGA cards support a non standard low-res mode with 64 colors. The old design of the adapter should support that with hi-res mode setting. Is there a way in the new adapter to ovrerride the autodetection to allow this mode?

Question I built one of your MCE adapters and the only issue I have is I am getting jitter on the top and bottom of the display. This is on my Tandy 1000EX using a GBS-8200. I have tried using several different LCDs problem appears on all of them. If I use a RGB to HDMI output works just fine and I have a stable sync

So this is all I need to convert CGA TTL out from an old PC to to VGA in on a LCD monitor? What is the US$ estimate to order board and parts?

7:00 is the frequency different or not? it says 60/50 but you say 60/60 and the graph looks lined up

Nice! Can this go in the other direction? I have several MDA monitors)

I so need one of these to convert a model 3 24hz EGA to 15/31hz VGA. HELP

Did you try original HGC 720 × 350 on BL702A? I see you setup CGA mode on it.

I built 5 of the first version from the project file on pcbway. Really fun to build but I couldn’t get them to work for some reason. Maybe my monitor doesn’t support the 15KHz signal?

Does anyone know where I can acquire a 9 pin video cable? Will a DB9 Male-Male cable work?

Can you show some oscilloscope traces, on what and what not these GBS8200 boards accept as valid RGBS signals and what not? I have an old CNC mill with Motorola 6845 graphics, so likely MGA signal with H/V out. V-sync is 50Hz, H-sync 15.5kHz. XORed H and V sync, to get composite sync, my XOR composite sync is TTL high with short negative H-spikes (when V sync is low) and TTL low with short positive H-spikes (when V sync is high). Color is monochrome TTL, which goes directly on green input. But I get "no signal", no matter what I try.....

Is anyone on here familiar with the GBS-8100 - essentially the inverse of the GBS-8200 VGA to CGA. But again I'm not sure if it's CGA or Analog RGBS that it outputs. If I connect up to a CRT TV via Scart I get an image, which is perfectly fine. If I use a sync separator and connect up to a 15Khz VGA monitor I get a blank image - not a 'no signal', just a blank image which suggests the sync is fine but it can't read the RGB signals which would make sense if they are CGA. Therefore your converter would be able to help except that the output from the GBS-8100 is just the 5 wires R, G, B, Csync and GND. I think to convert from CGA to RGBA I'd need an intensity signal, is that right? Or is there another way?

So still need a 15khz VGA monitor ?

Hello! my friend has a 486 dx2 machine. it doesn't boot or post. we tried to repair it but we failed. We are from Italy, can we send you the board to repair it

Not work for me, I try convert 15khz rgbhv signal from old cnc with 9pin connector (6 wires) and use this adapter and gbs8200 (pcb made by jlpcb) and latest software version and i can see that monitor is struggling with signal, it shows a fragment of a picture for a second but most of the time no signal. I have a better result with cd4030 xnor gate and few exit resistors

How the heck did you do that with a GAL?

Can i have the (or one) of the engineering samples?

I have the old one. Can I rework it to this Version? Greeting!

Meh. I ordered the previous version PCBs just five days ago :(