Greenish tinted screen Macintosh Centris 650

[NickNick]

Hello. Was wondering if anyone out there knew what would cause a Centris 650 to have a green tint to everything on the screen. Even the grey start up screen has a green tint; Like a light green, pea green tint. I tried it on a CRT monitor as well as an LCD monitor. Both yield the same results. Machine works perfect otherwise, no other issues. Its tolerable to use but worse on the LCD as its more detailed it seems like and the green looks more intense. I'm using the machines built in video. Any input would be much appreciated.

Thank you so much.

 

[yuhong]

I think this is called sync on green. I think the "Basic Color Monitor" extension was intended to correct this when a VGA monitor code is detected, which is included in later system versions. Which VGA adapter are you using?

 

[Ferrix97]

I had a Quadra 700 do the same thing, once I installed System 7.5, the problem went away.

Sometimes it comes back when I boot 7.1, but as soon as I boot 7.5, it goes away!

Does your machine have upgraded VRAM?

 

[NickNick]

Thanks for your replies. I am using the Mitsubishi adapter with the six dip switches. I hooked it up to an actual Macintosh monitor and its much better although I can tell the white is not as white as it should be from that monitor. Does have an even slighter tint of green. The OS is system 7.5.3 revision 2. I also have a Macintosh ii video card that I installed in there. The machine sees it but I am un able to get the monitor to show anything. Just stays in stand-by mode only.

I tried putting another stick of V-ram in there and it did the same results however maybe because the V-ram stick says for LC only. I'm just using the stock v-ram installed. I do have a copy of system 7.6.1 which I could try out.

 

[yuhong]

Yea, try changing the DIP switches.

 

[uniserver]

yup, all you have to do is make sure your Pram battery is charged.

Once you boot 7.5 and your db15 to vga adaptor is set to VGA.  The screen will return to normal.

and the change will be automatically saved in pram.

if your pram battery is dead and you boot 7.1 or lower.  It will stay greenish, until you boot back into 7.5 and it will return

to normal.

 

[NickNick]

Hi there and thanks for the updates. Wow...I so cant believe that was the issue. Its weird how some of these Macs are more finicky than others lol. Still lots to learn about these Macintoshes but all very fun to work on and get going again. Thank you again.

 

[uniserver]

yeah if you pram battery goes dead,  otherwise if your pram battery stays charged then you would never notice.