IBM 5154 EGA Only displaying 8 Colors

[marcampion]

I have an IBM 5154 EGA monitor and an IBM AT 5170. I am running an Oak Technologies OTI-037c Card. The card works with another monitor.

The issue is that it's not displaying 16 colors (nor does it give me the option to tweak any of the other 64 available colors--see attachment)

When I run Norton on the system on the Video Summary page (see attachment) it says that it is running Video Mode 3. Anyone know what that is or how to change it?

I think it must be something on the BIOS or somewhere else, I don't think it's something on the monitor.

Any leads would be appreciated!!!

 

[reenigne]

Video mode 3 is just colour 80-column text mode - that's not the problem. The intensity bit is getting from the card to the monitor as well - you can tell because colour 6 (brown) is distinguishable from colour 14 (yellow). This (and the fact that the card works with another monitor) means that the problem is with the monitor. Try adjusting the brightness/contrast controls. If you can't get better results that way, the monitor may need some internal adjustments.

 

[modem7]

When I run Norton on the system on the Video Summary page (see attachment) it says that it is running Video Mode 3. Anyone know what that is ...

See the video modes listed at [here].

Try adjusting the brightness/contrast controls. If you can't get better results that way, the monitor may need some internal adjustments.

I think I have been able to reproduce what the OP sees by adjusting down the contrast control on my IBM 5154 as far as it goes.
When I adjusted the contrast control down to the minimum setting, the major changes were:
* 'Brown' changed from brown to red
* 'Grey' changed from grey to black

Excepting for yellow, the 'bright' versions of a colour darkened and became almost the same as the 'non-bright' version of the colour. For example, 'bright red' looks the same as 'red'.

(Info: On a 5154, turning the front panel's contrast control knob only works when the knob is pulled into its outer position.)

 

[VileR]

The intensity bit is getting from the card to the monitor as well - you can tell because colour 6 (brown) is distinguishable from colour 14 (yellow)..

Wouldn't EGA be using 6-bit RGB, rather than an intensity bit? All the other intense colors look the same as their darker counterparts, so I'd say it's both of the green bits that are getting from the card to the monitor.
Still, pretty much the same conclusion - contrast control adjustment.

 

[marcampion]

Hey Everyone!

Thanks for the replies. Yes I've tried playing around with the contrast and brightness knobs, but it's not that.
I know in the photo I attached brown and red might look different but that is more due to the contrast in the photo than the contrast on the screen. On screen they look exactly the same.

The limited color palette is most evident when playing games-- maybe not to everyone, but if you're familiar with Sierra games, the colors were just off, and less of them, in a really dramatic way-- not something that would be just slightly off if the image was flatter and less contrasty. I'm attaching two Roger Wilcos-- how he's supposed to look and how he looks like on my screen.

As you can appreciate, the situation is DIRE.

 

[modem7]

I have an IBM 5154 EGA monitor and an IBM AT 5170. I am running an Oak Technologies OTI-037c Card. The card works with another monitor.

An EGA monitor ?

 

[modem7]

In case relevant later, at [here] is the colour processing circuitry of the IBM 5154.

 

[marcampion]

In case relevant later, at [here] is the colour processing circuitry of the IBM 5154.

thank you!!! this is a foreign language to me but if i can find someone who can repair it, it might be very useful to them.

i tried installing a second video card but the AT is not reading it at all. just gives me the long beep followed by two short beeps error message, just as if there was no card installed.

is there anything else i should be doing besides connecting the card and making sure everything is plugged in properly?

 

[modem7]

thank you!!! this is a foreign language to me but if i can find someone who can repair it, it might be very useful to them.

Normally, in this kind of situation, you first isolate cause to unit. Is it the card or is it the monitor? You wrote, "The card works with another monitor.", which on reflection, is not enough information. The Oak Technologies OTI-037c does both VGA and EGA, and for all we know, you tested the card on an VGA monitor and incorrectly assumed that if the card works at VGA, it must also work at EGA. Hence my question at post #6.

A possible way forward (for whomever):

An observation

In mode X, colour Y is appearing on-screen as colour Z.

Diagnosis

Run software that sets mode X and all of the screen to colour Y.

Mode X is an EGA mode, and therefore:
- Vertical sync pulses are negative going.
- 6 channels ('r','g','b','R','G','B') of colour information are output by the card to the monitor.

At the 9-pin D connector of the card, verify that the vertical sync pulses are negative going.
At the 9-pin D connector of the card, verify that each of the six channels is as expected (TTL high or TTL low) for colour Y.

If those two verified good, then 5154 monitor is at fault; look at what is being presented to the 5154's colour mapping ROM and depending on result, work backwards or forwards through 5154's colour circuitry.

After fix, repeat above if there are still other colours not appearing as expected.

i tried installing a second video card but the AT is not reading it at all. just gives me the long beep followed by two short beeps error message, just as if there was no card installed.
is there anything else i should be doing besides connecting the card and making sure everything is plugged in properly?

* Verify that the card is sitting deep enough in the ISA slot
* Try a different ISA slot
* Clean the card's edge connector
* Re-seat any socketed chips on the card
* Verify that video switch (SW1) on the motherboard is in the correct position