Quadra 800 - VRAM only showing 256 colours

[AlpineRaven]

Morning all, 
Am I missing something with this Quadra 800, without any VRAM sticks, it only shows 256 colours.

When I add 2x 512k VRAM or 2x 256k VRAM in - it still doesn't show Thousand of Colours (or Millions). (only shows 256 colours thats all even tho changed over VRAM sticks which they're known working)

Doesn't matter if its in 7.1 or 7.6.1

Cheers

AP

 

[AlpineRaven]

update: Pulled the HDD out and put in Quadra 650 - basically very similar boards - Quadra 650 does show thou of colours on that HDD.

Pulled the VRAM out from Q650 and put them in Q800 - still showing 256 colours. Tried zapping the PRAM - not changed.

Logic board at fault?

I recently got Q800 about a month ago and I do not know the history of it.

Cheers

AP

 

[Byrd]

Hi AP,

I'd be cleaning the contacts of the VRAM slots, VRAM modules with electronic solvent cleaner.  Have been playing around with VRAM in various Macs of late and they can be picky - check also if they are 80ns or less (-8 or something on the modules themselves)

JB

 

[Unknown_K]

What resolution are you using?

With 512k of VRAM, the system is capable of supporting 512x384 at 16-bit color, 640x480, 800x600 and 832x624 at 8-bit color, and 1024x768 and 1152x870 at 4-bit color. With 1 MB of VRAM installed, it can support 640x480, 800x600 and 832x624 at 16-bit color and 1024x768 and 1152x870 at 8-bit color.




Standard VRAM:



512k, 1 MB*


Maximum VRAM:


1 MB*



Details:


*512k of VRAM is installed as two 256k VRAM SIMMs and 1 MB of VRAM is installed as 512k SIMMs.

 

[AlpineRaven]

Its both  640x480 and 832x624 only showing 256 colours doesnt matter if you have VRAM or not.

As I've confirmed its not the software issue - its hardware issue.
I've washed the logic board and closely inspected the slots - seems to be normal. I'll rest it tonight as I'm buggered

Cheers

AP

 

[Unknown_K]

You do know how to change color depth in the control panel correct?

 

[Cory5412]

Have you had an opportunity to look at TechTool or Apple System Profiler to confirm the system actually knows the VRAM is installed?