• Hello, Guest! Welcome back, and be sure to check out this post for more info about the recent service interruption and migration.

Q700 with a black screen on startup.


Well-known member
Exactly what the title says. The machine boots into the OS, and I know because I can eject a floppy with openapple-E. So everything is fine with the SOFTWARE....

Here's what I've done...

Zapped the pram

made sure the battery has 3.5 volts

checked the video cable

reseated the ram and vram

The only thing I can think of is it's the MAC -> VGA adapter I have on the thing. But I didn't change the settings of the DIP switches since the last time it worked... I dunno. Maybe the vram went bad? It just suddendely happened when I restarted it one time, I don't know what's going on.



Well-known member
Check your adapter, nonetheless. If the correct sense pins are not grounded, the Mac will believe that there is no attached display, and therefore not attempt to drive it. Adapters with DIP switches are easy to derange without noticing, no matter what memory assures you to be the case.




LC Doctor/Hot Rodder
Out of curiousity, do you have an old Apple display you can use, just temporarily?



Well-known member
No, no old apple display. Just an old Dell LCD :'(

I got on ebay and for about $3, I got a Mac -> VGA adapter withouth the DIP switches. So we'll see how it works then.



Well-known member
Well, I played with the DIP switches today. And it's what's going on with the monitor that's weird. Now the monitor is fine, it works with my macbook, but the quadra...

Normally, when the monitor doesn't recieve a signal over VGA, it switches over to the DVI input of macbook. But it doesn't with the quadra. The monitor has a choice between two inputs, the DVI and VGA. When one signal isn't being recieved, it switches to the other. So the monitor is receiving a signal, it's just that the signal is black.

Can anyone shed some light on this?

And does anyone have a nubus video card that doesn't require installing a driver, or a Q700 logic board for sale? Cause I think that's what it's coming down to.

It's a shame, really. I was getting this thing out, buying some of the games I grew up on to play on this thing, and was even going to start programming this little project I have in mind. And all of a sudden my quadra doesn't work. boo.



Well-known member
Flat PRAM battery in the Q700? In which case the Q700 may be defaulting to 640 x 480 at funky Apple frequency.

Post a few photos of the Mac --> VGA adapter, in case somebody knows the DIP switch settings.



Well-known member
well, i didn't want to do it, but I did. and now it works. joy. The brute-force method of figuring out DIP switches.

I tried them all. I would have done all 1024 different combinations, but it worked at 0001100011. so does anybody want to figure out how many cominations I tried? I think it was less than 200....

thanks for all your help, guys.