Quadra 650 and Dell 1708 Fpt results in Green Hue.

[sailingdarter]

So I am kind of stumped. Most of my childhood Mac History is from Using a Mac Plus -> Mac SE and then our family just jumped from that to a PowerMac 6100/60. So this is my first experience with "owning" 68040 Machine (other than LC575's from Jr High in the late 90s)

So I recently acquired a Quadra 650 which has a NuBus card of some sort. I am sure it will need a recap but it is working for now. But when I plug in the display that is named in the title, I get a green hue both on the built in motherboard video port and the NuBus display card. I suspect that this may be a Sync On Green issue since I know that a lot of computers from this period did things that way. But what surprised me is that the built in video is doing this. I figured that this was confined to "higher end" workstations from the period like Suns, SGI and NeXT machines. So I am a little surprised that I am seeing this on a 68K Mac

Now when I do an "Auto Adjust" on the Dell Monitor. The green hue will go away for a second or two but then it will come right back.

I know that this monitor is good because I have used it with a 6100/60 (same childhood machine) As well as other machines in my Mac collection which are:

PowerMac 8500/180 (Built in Video)
PowerMac 8600/350 (Both Built in Video and PCI Card Video)
Biege PowerMac G3/333 (Both Built in Video and PCI Card Video)
PowerComputing PowerTower 225 (PCI Card Video)

As well as a Pentium 3 Box from 1999/2000 era


Is my suspicion correct? What would be a solution for this.

Thanks in advance

Best Regards

SailingDarter

 

[MacTech68]

One thing to remember is that the Mac only looks at the display sense lines at initial power-on.

The sense lines are 3 pins on the video connector that (in various combinations) tell the Mac what type of monitor is connected.

So, if you have a video adapter with switches, you need to cold-reboot the machine for it to see that change.

Secondly, the onboard ROM will only recognize certain monitor types (as set by the 3 sense lines). When paramater ram (PRAM) battery is flat or renewed, the initial power on video setting is reset to the default for the monitor type detected.

Depending on which operating system version and/or Apple Display Software is installed, will determine what further resolutions are available after boot-up from the "Monitors" Control Panel from the 'Apple Menu'.

Oddly, the manual for your monitor (https://downloads.dell.com/manuals/all-products/esuprt_electronics/esuprt_display/dell-1708fp_user's guide_en-us.pdf) Page 7, states that it does support 'Sync On Green' which would seem to indicate that it has sync separator built in. However, IIRC, Apple's own Sync is more often Composite Sync - when the Mac is NOT given VGA or SVGA monitor type sense on power-up.

You may find that even if the display looks green/incorrect on initial power-up, when the display driver overlay extension(s) load, the screen will change to a better/preferred setting.

You may need a different display adapter, as some are extremely basic, have no or varying number of dip switches for setting the initial display type for the Mac to recognize. A 10 switch adapter seems to have the extra options.

Having said all that, even if your 650 has maximum VRAM, you are still only looking at 16bit color at 800x600 resolution (ie, thousands instead of Millions of colors). https://cdn.preterhuman.net/texts/computing/apple_hardware_devnotes/Mac Centris(-)-Quadra 800.pdf Page 22

Remember that LCDs have native resolutions. If it's higher than the best setting the Mac's video port can provide, it's going to look somewhat "fuzzy".

YMMV

Hope this helps.