VOGONS


First post, by InbetweenDays

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I am attempting to restore an old portable LCD-386, which looks basically the same as this one.
I'm not able to properly test the LCD because the video card isn't working. It's a Cirrus Logic CL-GD610/620 based card with 256kB, and since it would prove almost impossible to find a replacement, I would like to repair it if I can. Here's a pic:

LCD Card.jpg
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On startup I get BIOS error beeps - 1 long and 3 short, indicating a video card failure. The computer does boot, albeit with no display, so I was able to use debug.exe to get a copy of the ROM. The ROM description is:

Stingray Rev 4+, VGA BIOS Version 2.22
Copyright (c) Cirrus Logic Inc. 1989, 1990.
Copyright (c) Award Software Inc. 1984-1988. All Rights Reserved.

The 8-bit checksum is 0. The 16-bit checksum is non-zero, however I've seen other ROMs with a non-zero 16-bit checksum, so I'm not sure which one is used or whether the 16-bit checksum value is also stored in the ROM. Thus my ROM seems to be ok but I can't be 100% sure. I did however download a copy of the GD610/620 BIOS from Vlask's VGA museum site (thanks again Vlask!) and got an EEPROM burnt with that, just to see if it would work. No luck - but the error is slightly different. I still get 1 long and 3 short beeps but now they are much longer.

With the original ROM it's like this: Beeeeeep bip bip bip
With the ROM from Vlask's card: Beeeeeeeeeeeeeeeeeep beeeeep beeeeep beeeeep

I'm not sure how significant that is. By the way I have also tested the card in a 486 and 6x86 with the same symptoms (they all have AMI/Award BIOSes).

So... does anyone have any suggestions, or experience fixing old video cards? There are no broken traces I can find or burnt spots or any other obvious visual clues. The RAMDAC is probably the easiest thing to replace, followed by the memory chips. However with those I'd have thought the card would still POST but just have a blank or garbled display. Oscillators perhaps? Those are all within my soldering skills, but replacing the chipset would be beyond me.

All help gratefully accepted.

With thanks,
Stu

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 1 of 22, by InbetweenDays

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A little bit of further information:
The card has 8 dip switches (external), and one 3 pin jumper, marked JP1. In the pic you can see it just near the yellow wire to the left of the switch block. Removing the jumper or moving it to the other 2 pins has no effect, nor does trying the card in an 8-bit slot (and again trying the jumper in case it's for 8 vs 16-bit selection).

I can't find anything about this card online (stason.org etc) but I have tried a few switch settings based on possible similar cards. Nothing makes a difference - but then, I would not expect it to. IMHO it would be a poorly designed card that could be easily "broken" via externally changeable switches.

The toggle switch and yellow/red wires are for turning the LCD on or off. That connector goes to one on the PSU which I think is meant to supply +12 and -22V - the toggle switch controls whether it's sent through to the brown connector at the top of the video card. (See pic of PSU connectors below).

The PSU doesn't work either, but by connecting gnd and 12V to the right pins on the video card, I was able to at least power on the LCD panel and see that the backlight is working.

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It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 2 of 22, by Predator99

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What kind of connector does your card have? Is it standard VGA? If yes, did you try another monitor?

As it is a standard ISA card: Did you put another VGA in your portable to see if it works?

Reply 3 of 22, by InbetweenDays

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Yes - it has an external VGA connector, and internal 20 pin connector for the LCD panel.
I've tried it with two different CRTs, and the LCD panel (and nothing connected). I wouldn't expect error beeps from not having a monitor connected though.

The error beeps follow the card to different machines - the 386, 486, and 6x86 all do the same thing. Other VGA cards work fine in the portable, using an external monitor... but I'd really like to get the inbuilt LCD panel working!

Cheers,
Stu

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 4 of 22, by InbetweenDays

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Ok, I take that back re the error beeps with monitor disconnected since I just had the same problem when booting my 6x86 (different VGA card) with the monitor cable out...!

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 5 of 22, by InbetweenDays

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Predator99 wrote:

What kind of connector does your card have? Is it standard VGA? If yes, did you try another monitor?

You did get me thinking though...

The only visibly unusual thing about the PCB is where 3 VGA connector junction points appear to have been left deliberately unsoldered, as you can see here:

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I checked and sure enough, they are for the monitor ID pins (4, 11 and 12). I guess this makes sense as the switch block is probably used to specify the monitor type so that the card would still work (with the built in LCD panel) without an external monitor connected.

Thus perhaps if there was a problem with the switches or the resistor packs then the computer isn't seeing that a monitor is connected and hence the error beeps. Theoretically pin 11 to ground would indicator a colour monitor not supporting 1024x768, so I tried carefully shorting the solder point for pin 11, but no luck. I also tried it with the LCD ribbon cable connected in case the card needs to see the LCD panel, but again, no difference.

I found this post suggesting possible switch settings but had no luck using that as a basis for more testing. I could sit down and go through all 256 combinations of the switches (768 if you include the 3 possible jumper positions!) but I have a feeling that wouldn't make a difference either.

The only other clue about the switches is found in these error messages in the ROM I extracted:
The VGA monitor switches, sw 1-2, are incorrectly set.
The VGA state switches, sw 6-8, are incorrectly set.
These roughly line up with the post linked above - and also suggest that the BIOS would displays error message even if the monitor type selection is incorrect. Since the LCD panel can be turned off, it seems a reasonable assumption that at least something would appear on an externally connected monitor, regardless of type & settings, rather than just getting obscure error beeps.

I could be way off track though. Without being able to compare with card known to be working, it's all conjecture. 😀

Cheers,
Stu

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 6 of 22, by Predator99

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I have never seen a Bios complaining about a missing Monitor..but may be.

I am not sure in your case if the problem is related to the VGA but to the LCD? What kind of monitor is this? Is it analog or digital (EGA/CGA style)? Do you have the chance to connect another Graphics card to it?

Reply 7 of 22, by InbetweenDays

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No, it's the built-in panel - see the first link in my original post for pics of a similar one. It connects to the card with a 20 pin ribbon cable (see my first pic; connector is just to the left of the RAM and it looks like the same PCB design may have been used with other connector types). It can be turned on/off using the external switch on the graphics card (again, see pic of the card and also the PSU). So no, this is specific to the panel and finding an alternative controller would also be nigh impossible. (I've already checked out VGA driver boards on eBay / aliexpress but the suppliers can't say whether it would work with my panel since it's so old - the only model numbers they can check are for newer panels, eg from laptops).

The card supports using an external monitor instead of the LCD - the toggle switch turns off power to the LCD. So I can't imagine that you'd need to have the LCD turned on to even be able to boot the PC.

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 8 of 22, by incanus

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Old thread, I know, but I have acquired a similar machine (see my other posts) and am in the process of debugging the motherboard, which can't even POST. In between bouts of frustration with that, I am attempting to get the VGA card going in my other PC, which is ATX but has one ISA slot. No luck so far, and I'm going to next try connecting grounds on the ATX and the external, special (also +12 & -22V) AT supply to see if I can power the LCD off of my ATX system (and thus also verify the VGA card works).

Happy to scope out anything for you on my card, though as of yet it's not confirmed working.

Reply 9 of 22, by Ozzuneoj

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Check the tantalum capacitors for shorts. These aren't the small bead-like yellow ones (those are ceramic caps), but the larger\taller yellow capacitors. I can see three: One near the ROM, and two near the VGA port.

As old as that card is, this is what I would lean toward.

In a pinch I've replaced these with a standard aluminum electrolytic cap of the same values to get an old video card working and I can't say I've ever noticed any problems. Granted, the best replacement would be another tantalum or at least a good quality low-esr modern capacitor.

EDIT: Oy... old thread.

Time Machine = FIC PA-2013 2.1 - K6-2 500 - 256MB PC-100 - TNT2 Pro 16MB AGP - Labway Yamaha YMF719-E - Midiman MM401

Reply 10 of 22, by InbetweenDays

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Yep, old thread 😀 But thanks for the suggestion! I checked those caps for shorts and they seem fine. Not sure whether to say "unfortunately" or not... when I read your post I got hopeful, because that would be an easy fix, but alas...

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 11 of 22, by incanus

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I did eventually get my card (and whole machine) to work, so I've now got a great reference version of an LCD-386 should you need any details.

Re: "386-LCD" portable unable to POST; continuous beep; no video

The machine came with floppies containing EAGLE.EXE and SWITCH.EXE which allow for console, GUI, or flag-based hands-off setting of various parameters like CGA/EGA/VGA/MGA, LCD or CRT, "VGA fast mode", and other details. I would like to eventually reverse engineer them and figure out how to use the functionality in other OS's such as Linux.

Reply 12 of 22, by Jonas-fr

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Vogons is amazing, I've got the very same card as you InbetweenDays (down to the 2.2 BIOS version) but albeit in the working state in a 486 lunchbox machine ! I'll dump the BIOS as soon as I can find my TL866 😀

My problem is making it display anything on an external VGA monitor (no signal with my current dipswitches settings OFF-OFF-ON-ON-OFF-ON-ON-OFF (12345678)).

@incanus: would you be so kind as to upload these two utilities? I've got EAGLE v5.03 but maybe you got another version and also I haven't got SWITCH.EXE. Thanks !

Reply 13 of 22, by incanus

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Sure thing, here is EAGLE.COM, SWITCH.COM, and a third one called VSCREEN.COM that I think is related but only indicates that it's already loaded when run after the first two. I'm not sure of the versions offhand.

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Reply 14 of 22, by Jonas-fr

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I can't thank you enough incanus, your version of eagle is a bit older than the one on Vogons drivers (4.01 vs 5.03) and thanks to it I've been able to run it and switch to my external display thus confirming that my card was OK !!

I took the liberty to post these utilities on the dedicated topic in order to let them be uploaded on Vogonsdrivers.com, I hope you don't mind : )

Reply 15 of 22, by InbetweenDays

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Jonas-fr wrote on 2020-07-10, 14:04:

Vogons is amazing, I've got the very same card as you InbetweenDays (down to the 2.2 BIOS version) but albeit in the working state in a 486 lunchbox machine ! I'll dump the BIOS as soon as I can find my TL866 😀

That's fantastic - thanks! It will be interesting to compare and see if my BIOS is ok or not. 😀

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 16 of 22, by Jonas-fr

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Here's the promised dump of my Stingray Rev 4+ (VGA BIOS Version 2.22) Cirrus Logic GD610/620 based video card. Hope it helps reviving yours, let us know !

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Reply 18 of 22, by InbetweenDays

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Hi, thanks so much for dumping your BIOS and posting it here... it's taken me a step further but won't fix my card unfortunately - it did at least let me verify that my BIOS is ok. I did a FC /B on the two files and they're identical!
Next step... some desoldering perhaps...

It don't mean a thing if it ain't got 5-pin DIN.
Roland addict and founding member of the Association Of Molex Haters

Reply 19 of 22, by Jonas-fr

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Thanks for your feedback. Seeing how the ramdac (Suntac GS02760-50) is socketed should give us a hint that maybe this was a problematic chip that would have to be replaced when RMA'ed.

If I were you I'd start by replacing this chip !