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Help identifying this EGA card

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First post, by FAMICOMASTER

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As some of you may know, I'm working on a Turbo XT machine. I've got some color monitors coming in the mail, and I thought I'd give them a try.

There's just one problem: I don't know how to set up some of my EGA cards which I plan to use.

I've got an early revision ATi EGA Wonder that I'm going to use in my turbo AT with the nicer of the two color monitors, until I can pick up a period-correct "CTX" VGA monitor I saw at a local junk store. I know they still have it, it hasn't moved from it's spot in 10+ years, I'm going to offer them a fairly low amount of money for it and see what happens.

I've got *several* other EGA cards though, many unbranded, a couple Video7, a couple Cirrus Logic... All from the same junk store. They had a box of them and I bought the whole thing, cardboard box included. $10 makes me think it was a steal. I've been able to "identify" many of these cards and set their jumpers, but I want to use this one particular card with my XT.

It's an unbranded card, I know it's EGA because it has the Chips & Tech PC82C43x EGA chipset onboard. It came out of an XT clone with the same motherboard, so there should be no trouble using it in this machine.

It's got a bank of 6 switches (SW1), two 2 pin jumpers (P4 and P5), three 3 pin jumpers (P1, P3, and P6), and a 6 pin jumper (P2) labelled "L1 L2 L3," which I assume is the parallel port address. It has the 32-pin EGA feature connector, a light pen connector, the 9-pin TTL video connector, and a 25-pin Centronics parallel port.

I would love to use this card in this machine, it's period correct, it's using a clone chipset, just like the motherboard, and it's got all the features I want. I just need to set the switches and jumpers so I can test it first with my monochrome monitor and then use it with my CGA monitor.

Here are pictures of the card, front and back:
MVIMG_20191013_231943.jpg
IMG_20191013_231955.jpg

The only markings on the board itself are: "P.C.C." in the lower center, "PCC114058" on a sticker to the left of that, "MADE IN TAIWAN R.O.C." in the top left, "UNITECH 0001" on the bottom right on the back, and "8707" above that. I'm pretty sure this is a date code.

"Unitech EGA" doesn't bring up anything meaningful on Google, and no such entry exists for it on TH99. I looked through every single listing under 8-bit ISA video cards. All of them, not just EGA, and found nothing similar enough to configure this. Apparently EGA cards with parallel ports are exceedingly uncommon. All the more reason to figure this one out and use it.

I would be happy to provide any additional information about the card that I know about. Thank you in advance.

Reply 1 of 21, by data9791

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I don't know how helpful of a lead this is, but I found a card with a very similiar layout on Google images:
https://www.google.com/imgres?imgurl=http%3A% … iact=mrc&uact=8
302123004_fb4aa790-b190-4fc9-8a1c-4bec5f853fe1.jpg

From a dead auction link apparently.

Reply 2 of 21, by FAMICOMASTER

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Wouldn't be surprised if there were more than one variation of this card out there - It did come out of a generic turbo XT clone, after all.

Reply 3 of 21, by FAMICOMASTER

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Is there a chance that another card based on the same Chips & Tech chipset might have the same switch settings?

Reply 5 of 21, by FAMICOMASTER

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Just tried all of the switch settings listed there... And then some.

Got fed up with it and went through all 64 possible combinations on the switch bank. Not one of them did anything more than flash green bars onto the display for a second and disappear.
It must be either the jumpers or a combination between switches and jumpers.

I can rule out P4, P5, and P7.
P4 and P5 connect directly to the feature connector, which suggests they are for external oscillator or sync signals, which I am not using. Leaving them disconnected will change nothing.
P7 is a connector for a light pen, which I do not have and does not matter for these purposes.

P2 is labelled "L1 L2 L3," which I think is safe to say selects the port address for the parallel port. I will be using it as parallel port #2 (278) since my multi I/O card (which I also can't find good jumper settings for) occupies 378, and I plan to potentially force this EGA card to operate as CGA (if I can figure out HOW) and use my MDA card in conjunction for a dual monitor setup on it. It's parallel port is hardwired to port 3 (3BC), and the ONLY jumper on the card is to enable or disable the parallel port, nothing concerning it's address.

I will come back with updates if I have any.

EDIT: Moving jumper P1 from pins 2&3 to 1&2 causes a video POST error. I suspect this to be the EGA port address.
EDIT2: Moving jumper P6 from pins 2&3 to 1&2 does not change what is shown on the monitor with any of the 64 switch settings. Trying P3 now.

Reply 6 of 21, by FAMICOMASTER

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FINALLY! SOMETHING!

With jumper P3 in the 1&2 position, P6 in the 2&3 position, and setting SW1 to:
Off On Off Off Off Off

I get a display on my monitor as it should!
It's only detected as a monochrome card, however, so I'm going to keep messing with it until it works.

Jumper P2 in the "L3" position sets the parallel port to 278. What? Setting it to "L2" seems to set it to 378 or disable it entirely. Putting it on "L1" sets it to the third address at 3BC. Weird.

Reply 7 of 21, by FAMICOMASTER

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Upon further investigation, P3's position does not matter and the computer will boot with monochrome mode regardless of it's position.

I think it may be for the parallel port interrupt.

Reply 8 of 21, by FAMICOMASTER

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The first 4 switches seem to set the monitor type. The 5th switch ALWAYS hangs the machine, and the 6th switch doesn't seem to be connected.

Reply 9 of 21, by FAMICOMASTER

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I think I've done it, ladies and gentlemen. I've completely figured out what most of the switches do!

I'm going to type up a thing of my findings and post it here in a jiffy

Reply 10 of 21, by FAMICOMASTER

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This is about the best I could get trying it with just a monochrome monitor. I really need my color monitor to hurry up and get here, or to get an EGA monitor already

Is there any DOS utility out there to dump video card ROMs so I can put that with it?

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    ega_card.txt
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Reply 13 of 21, by CBM

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nice!

I think I have that same EGA ISA card somewhere!

I remember spending days messing with jumpers on all kinds of weird cards back in the day! 😀 Why I remember that as enjoyable, I will never know 😀

Main PC SPECS:
CPU: AMD Ryzen 5 2600
GPU: Powercolor Red Devil Radeon RX 5700 XT
RAM: 8GB*4 Corsair Vengeance LPX DDR4 3200MHz
Motherboard: ASUS Prime B450M-A
PSU: Corsair RM850

Reply 14 of 21, by FAMICOMASTER

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Unfortunately, I need a working keyboard to use NSSI on the XT, so it will be a bit before I get the ROM. Or maybe i'll put it in my AT instead, who knows.

Reply 15 of 21, by Predator99

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Think I have some cards with the same chipset
Re: Heath 150-307-3 Chips EGA/VGA
Re: Is there a win3x EGA driver that supports more than 640x350 resolution?

In case your PC boots you can include the command to dump the ROM in the autoexec.bat. Maybe nssi has a command line option for it or use a script for debug.exe.

Reply 16 of 21, by FAMICOMASTER

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Predator99 wrote:
Think I have some cards with the same chipset Re: Heath 150-307-3 Chips EGA/VGA Re: Is there a win3x EGA driver that supports mo […]
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Think I have some cards with the same chipset
Re: Heath 150-307-3 Chips EGA/VGA
Re: Is there a win3x EGA driver that supports more than 640x350 resolution?

In case your PC boots you can include the command to dump the ROM in the autoexec.bat. Maybe nssi has a command line option for it or use a script for debug.exe.

They're a fairly common chipset. I have a big box of EGA cards, this one just happened to have a parallel port on it, so I picked it for this.

Well, I have no hard disk drive either. I have a DTC5150CI and a Seagate ST-225 I'm planning to install when the time comes, but I don't have a working keyboard, so I can't low level format it and make it useful. NSSI also won't fit on a single 360K diskette, so I'd have to compress it across two diskettes and run it from a hard disk... Which I will need a keyboard for!

I had a look at the command line options for NSSI and found nothing that looked like it could dump ROMs without launching, so that's not going to work. Is there a script out there for Debug that does not need a keyboard? I'd also be open to other options involving command line ROM tools that I can run without a keyboard.

Does the VGA output work well on that Heath card? I was looking at a similar one on eBay not too long ago.

Reply 17 of 21, by Predator99

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Dont have a DOS-PC in front of me at the moment (therefore below might not work...), but you can paste the input for debug in a txt file (dump.txt) and then execute
debug < dump.txt (add in autoexec.bat)

content of dump.txt can be:
n vga.rom
rcx
ffff
w c000:0

...and it should create the ROM dump in "vga.rom".

Heath card is a fantastic toy and output looks good.

Reply 18 of 21, by FAMICOMASTER

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Think it would be worth spending $20 on? I think it's pretty tempting. I want to use VGA on my 286 for most applications, but I also like my EGA monitor. I'm looking at a period correct VGA monitor sometime soon, too, so this would cover both bases. I also like that it's full length, I love seeing a machine packed with as much as you can fit in!

I'll try to dump the ROM but I can make no promises that it will work or that it will even fit on a diskette. It can only read 360K diskettes.

Reply 19 of 21, by FAMICOMASTER

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Now that I have a color monitor, I've been able to identify a few more valid modes for CGA and what I believe to be EGA.

Things that cause a "flashing cursor but machine boots" on MDA can sometimes cause a display on a CGA monitor. Just to test, I put an MDA card in and sure enough when it displays a flashing cursor on MDA it boots on the CGA monitor about half the time.

Likewise, a "flashing cursor but machine boots" on CGA can sometimes cause it to display on the MDA monitor instead.

I'm sure there's EGA primary / secondary modes as well, but I don't have an EGA capable monitor right now.

Also, I still don't have a working keyboard. Not even my IBM Model M works on the AT clone anymore. Some keys failed.