VOGONS


First post, by Jonas-fr

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I stumbled upon this video card on a really nice lunchbox 486 (basically a Dolch clone). The computer has an embedded monochrome flat panel hooked directly on the card (multicoloured wires at the back) but also got a VGA port on the bracket and a switch to select between LCD and external/VGA display. The cards also have dipswitches. The problem is that VGA output isn't working (no signal detected with neither of my two "tolerant" LCD (NEC Multisync and Dell U2410F)) and given there isn't any marking or FCC-ID on the card I cannot find any documentation about it to see how I can make the external display work. Maybe it's just a configuration (dipswitches) issue, or maybe the card is faulty on the external display circuitry.

Here's some (big) pics of it :

Overall view (we see the CL-GD610 from Cirrus Logic)
YQb2

Bottom view
SHzk

BIOS chip
7IzF

RAMDAC (never heard of MUSIC SEMI, curious name for a chip on a video card if you ask me !)
3YHR

This is the connector which goes to the LCD. It should carry data (video) and power (backlight) since there's only these cables running to the flat panel. Don't know about the pinout nor the protocol (akin to this flat panel controller protocol ?)
7nnU

And here are the current dipswitches states. I haven't tested the 256 combinations of it (I'm wary of changing them at runtime and don't want to reboot 256 times this machine : )
7mms

Thanks in advance for your help on this ! And if you've got info on the flat panel connector pinout and/or protocol I'm all ears since I would like to replace it with a modern 4:3 IPS while retaining external VGA connectivity !

PS: The BIOS isn't dumped yet but if that could help I'll put this on top of my todo list (I haven't my programmer with me yet so for now it's pretty low on the list)

Last edited by Jonas-fr on 2020-07-09, 22:41. Edited 1 time in total.

Reply 4 of 12, by imi

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yes, they are found on quite a lot of ISA era graphics cards, and if you google the model number you can even find a datasheet:
https://www.mikrocontroller.net/attachment/8545/TR9C1710.pdf

Reply 5 of 12, by Jonas-fr

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Thanks! I must admit that I saw my share of video cards but never noticed this brand. I'm adding the datasheet to my project folder and keep looking for the DPSW settings. I noticed this analysis of a closely related 386 luggable so I'll try the settings on mine:

http://oldcomputer.info/portables/hs386/index.htm

The DIP switches are following: […]
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The DIP switches are following:

1,2 - monitor spec:
ON, ON - Monochrome
OFF, ON - CGA
ON, OFF - 80x25 text + CGA graphics only
OFF, OFF - VGA.

3,4,5 - LCD panel specification:
ON,ON,ON - Sharp LCD 241/241 lines
OFF,ON,ON - 241/248 lines
ON,OFF,ON - 240/241 lines.

6,7,8 - Graphics emulation mode
OFF,OFF,ON - EGA
OFF,ON,ON - CGA
ON,OFF,ON - Hercules
ON,ON,OFF - VGA
ON,ON,ON - undocumented, behaves like VGA.
All other combinations should cause BIOS to notice about it on some available screen 😀.

Reply 6 of 12, by Jonas-fr

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I finaly found someone with the same card and the very same bios (Stingray rev4+, VGA BIOS version 2.2) here: Re: Help fixing rare CL-GD610/620 VGA card

I'm goind to dump the BIOS of mine to help him. Sadly given that it's a 2.2 BIOS the eagle utility isn't working ("Video BIOS Version 3.0 or later is required to run this utility"). I can surely patch this check but I wonder if it will do any good to my card. To be continued !

Reply 7 of 12, by imi

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I'll have to check my dolchs if any have the same card x3
but I only have one 486, and that one's a bit hard to take apart ^^, I think the others have newer chipsets.
but I think dolch used their own graphics cards in all machines.

also I don't really know if you could call those a "dolch clone" they probably just had the same OEM as dolch for their cases ^^

Reply 8 of 12, by Jonas-fr

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Yeah I think a more appropriate term would be lunchbox PC as it designates this exact form factor. Dolch clone was the word on top of my head when I wrote this first post. Thanks anyway for your help into seeing if you've got the same card ! Any tips is much appreciated and helps a long way !

Reply 12 of 12, by Jonas-fr

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Thanks predator99, indeed it seems to be the same card if not for the RAMDAC. We also share the same DIPSW settings I see. In the meantime thanks to the help of incanus I was able to confirm that my card was OK by switching via software to the external display.

Here's his post with the needed utilities (Eagle 4.01 and switch.exe): Re: Help fixing rare CL-GD610/620 VGA card

That settles it, thanks to all of you who chimed in : )