VOGONS


First post, by DaveJustDave

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I have it working on an RGB monitor, but can't tell if its CGA, EGA, etc (because i don't have a keyboard! aarggh!) I do know it's color, but thats all i can determine without having a working keyboard.

it has connectors for serial and gameport, built in parallel port.

2nd question, whats my cheapest way of getting a working keyboard on this thing? 83 key XT keyboards are super pricey on ebay.

thanks guys

I have no clue what I'm doing! If you want to watch me fumble through all my retro projects, you can watch here: https://www.youtube.com/user/MrDavejustdave

Reply 1 of 22, by luckybob

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tell me about it. I also need one of those keyboards for the 5150 i got last weekend.

First glance it is a JUKO G7-B, but its missing things like composite video out. The chip directly under the bank of resistors, starts with JUKO, can you give us the rest of the numbers?

It is a mistake to think you can solve any major problems just with potatoes.

Reply 2 of 22, by Ampera

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A initial glance I want to say it's MDA as they tend to have those parallel ports on them, but you said it's colour.

It's not CGA as a CGA card should have composite out. Not only that, but QFP mounting wasn't much of a thing when CGA was around.

I want to say it's EGA, but a very weird EGA card.

I could also be totally wrong, I mean for all we know it could be a Hercules compatible card. Can you give me the text on all of the major chips on it? I will try to look them up. Also maybe a picture of the back? This is the issue when you give low resolution unfocused images, I can't zoom in and read much.

Reply 3 of 22, by DaveJustDave

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thanks for your help! attached as few more pictures (pardon the dampness on some of the chips, i had just swabbed them with rubbing alcohol to clean the dust off)

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I have no clue what I'm doing! If you want to watch me fumble through all my retro projects, you can watch here: https://www.youtube.com/user/MrDavejustdave

Reply 4 of 22, by jesolo

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Doesn't look like it's a video controller.
Based on what I see, it's a combo mfm/rll hard drive controller with an rs-232 (serial) and parallel port (can't quite make out the shape of the connectors on the side to confirm the latter).

It also has a real time clock built in (the onboard battery might need replacement).

Reply 5 of 22, by DaveJustDave

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Its definitely a video controller. Plugged my EGA monitor into it and it puts up a display - which is what makes this a very strange animal.

it has FDD, serial, parallel, and joystick.

jesolo wrote:

Doesn't look like it's a video controller.
Based on what I see, it's a combo mfm/rll hard drive controller with an rs-232 (serial) and parallel port (can't quite make out the shape of the connectors on the side to confirm the latter).

It also has a real time clock built in (the onboard battery might need replacement).

I have no clue what I'm doing! If you want to watch me fumble through all my retro projects, you can watch here: https://www.youtube.com/user/MrDavejustdave

Reply 6 of 22, by Half-Saint

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Regarding XT keyboards, I see this question all the time. You don't have to buy an XT keyboard! You can just get an old AT keyboard because most of the early ones had a PC/AT or XT/AT switch on the underside. I even have one from the early nineties that has this switch.

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Reply 7 of 22, by jesolo

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DaveJustDave wrote:
jesolo wrote:

Doesn't look like it's a video controller.
Based on what I see, it's a combo mfm/rll hard drive controller with an rs-232 (serial) and parallel port (can't quite make out the shape of the connectors on the side to confirm the latter).

It also has a real time clock built in (the onboard battery might need replacement).

Its definitely a video controller. Plugged my EGA monitor into it and it puts up a display - which is what makes this a very strange animal.

it has FDD, serial, parallel, and joystick.

Yes, you're right. I counted the pins now and the connector on the far left is your FDD.
The other two are both more than 20-pin, which tells me it's connectors for serial or otherwise.

Reply 8 of 22, by jesolo

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Half-Saint wrote:

Regarding XT keyboards, I see this question all the time. You don't have to buy an XT keyboard! You can just get an old AT keyboard because most of the early ones had a PC/AT or XT/AT switch on the underside. I even have one from the early nineties that has this switch.

I recently managed to find a switchable XT/AT keyboard myself and it works quite well on my XT.
However, I'm not sure of the availability of these type of keyboards anymore.
Most people who still advertise these pre-Windows 95 keyboards probably don't even know it has a switch on underside (if it is switchable keyboard)
So, you will have to ask the seller of each keyboard to confirm.

Reply 9 of 22, by keropi

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Post a pic of what you see on the monitor, my guess is that it is a cga clone on a multi-function card.

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Reply 10 of 22, by luckybob

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In the image, there are two NEC chips. They are 16K x 4 ram chips. $5 says the the 2-pin white connector at the top of the card is the missing composite connector. In the other connectors on the left, you can clearly see "RS232C-2" Its just a matter of tracing the pins to the control chip to make your own serial cable.

It is a mistake to think you can solve any major problems just with potatoes.

Reply 11 of 22, by Tommaso72

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I believe I have the exact same card in my turbo xt. It is a Monochrome, CGA, EGA
G7-B
Juko
8-bit ISA
256 kb video ram

Some had composite out, others did not, which was some what rare. A very nice card. Hope this helps!

Tommaso

Reply 12 of 22, by DaveJustDave

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thanks for the responses. Upon closer inspection, i am noticing that just about every connector on this card is missing a pin.

both RS232 connectors are missing the top right pin. game port is missing top right pin.

the floppy controller connector is missing the top right pin - pin 34. I've never seen one with a missing pin before.

If you look closely, it doesn't appear to have been made without the pin - the pin looks like it was cut off flush against the connector.

does this make sense to anyone??

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I have no clue what I'm doing! If you want to watch me fumble through all my retro projects, you can watch here: https://www.youtube.com/user/MrDavejustdave

Reply 14 of 22, by h-a-l-9000

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You say you had it working, how about running a diagnostic tool like Checkit?

But it can't be EGA because:
a) no video BIOS
b) has a character ROM on board
c) Newest datecode 1987 - at this time EGA was rather new and needed almost a full size card - unlikely that it would fit into the little chip
d) only 16k DRAM - this leaves only CGA or MDA, but it's too much for the latter.

As was already said it might have a composite out because there is a transistor-resistors group. Clone composite out tends to be disappointing though.

Pins cut off is a method for keying, so you can't plug the ribbon backwards. The ribbon connector would have the matching 'pin hole' closed with a little piece of plastic.

Features of this card:
- Floppy controller (UM8272), guess not suitable for 1.44MB floppies, second crystal missing
- 1 serial port equipped (INS8250 + MC1488 + MC1489 soldered in, non-standard serial ribbon cable)
- option to install a second serial port (empty sockets)
- 1 parallel port (implemented in the ASIC)
- 4-axis game port (NE558)
- battery backed clock (MM58167) - only useful in XT systems, and with a driver
- the video, very likely CGA

1+1=10

Reply 16 of 22, by DaveJustDave

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Thanks for the insight!

At first I thought the missing pins were for keying but looking at a standard floppy controller pinout , pin 34 seems like it's a required pin. I've never seen a floppy connector missing this pin.

I looked at the connector on the cable and there are no blocked off holes.

I have no clue what I'm doing! If you want to watch me fumble through all my retro projects, you can watch here: https://www.youtube.com/user/MrDavejustdave

Reply 18 of 22, by Maeslin

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DaveJustDave wrote:

2nd question, whats my cheapest way of getting a working keyboard on this thing? 83 key XT keyboards are super pricey on ebay.

While it wouldn't be an 'original 83 key XT', this little project might prove useful. Allows hooking a normal AT / PS/2 keyboard to an XT computer.

http://hackaday.com/2017/01/21/attoxtkeyboard/

Reply 19 of 22, by luckybob

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The converter is a WONDERFUL thing to make. I got lucky and one of my AT keyboards had an AT/XT switch on the underside. So I dont need one. but there are more details here: http://www.vcfed.org/forum/showthread.php?264 … highlight=at2xt

I think there might be some pre-made PCBs available too.

It is a mistake to think you can solve any major problems just with potatoes.