Screen Not showing up on Macintosh Performa 475.

[4tified]

First of all, my name is Edward and I am fairly new to Mac collecting...not new to computers... anyway, I am having trouble with my screen showing up on my mac... I have a 15-pin VGA - Mac VGA connector (I'm not sure if it's called that or not), and I can't get anything on the screen when I turn it on. I've checked the processor seating, switched out the ram, then switched it back, I've checked the tightness of the vga connector and I tried 3 different monitors and they get no signal. When I turn on the mac, I hear the startup sound and hard drive activity, but nothing on the screen whatsoever... I've taken all the simple steps I can. It worked fine once before, so I'm not sure if the port is bad or what. Can I be missing anything here? I don't know how to get to the Mac bios either. Your help would be greatly appreciated. ThankS!
-Edward-

 

[dpaanlka]

A lot of those VGA - DB-15 ("Macintosh Video") adapters don't work very well on older pre-PowerPC systems.

There is usually some sort of switch where you can select resolution. Make sure you set it really low like 640 x 480.

It is possible that your newer (I assume) PC displays might not support the super low refresh rates that the 475 is putting out.

Also, open it up and check to see that you or somebody else didn't remove the VRAM modules.

Finally, there is no Mac BIOS.

 

[dpaanlka]

There is usually some sort of switch where you can select resolution. Make sure you set it really low like 640 x 480.

To clarify, a physical switch, set of jumpers, or selector knob on the adapter itself.

 

[4tified]

To clarify, a physical switch, set of jumpers, or selector knob on the adapter itself.

Well, the screen that I'm using now it pretty old (like 1992 I think) and I switched the selector to the lowest resolution and still nothing... I also checked the vram modules and they seem to be in place. Any other ideas? (thanks by the way for the info so far)

 

[dpaanlka]

Well if you're using a PC screen from 1992, then there is a very good chance it doesn't support the *high* resolution of 640 x 480.

Basically, PC displays and old Macs are not meant to be together and you'd be much better off finding an Apple branded display such as the AppleColor High-Resolution RGB Monitor, which will work with any Mac ever made with the DB-15 connector, from the Macintosh II right up through the beige Power Macintosh G3, and you can usually find them anywhere old Macs are. Great display to have to test older Macs, and if you foresee that you'd like to have a few older Macs around, I'd highly recommend it. Very reliable, very crisp sharp old display that was very popular and are a dime-a-dozen today. They support black and white all the way up to millions of colors in 640 x 480.

Until then, there is no real way to say whether your adapter is broken, your PC display is incompatible, or your Macintosh is broken.

 

[Warbrain]

Are you sure the computer still works? I had the exact same computer and after like 8 years it crapped out on me. I still have it, but it will not turn on for the life of me...

Great computer, though.

 

[dpaanlka]

Are you sure the computer still works? I had the exact same computer and after like 8 years it crapped out on me. I still have it, but it will not turn on for the life of me...

If it's making hard drive noises it probably is still working. I have dozens of Macs from this time period and even older that all work fine.

 

[Warbrain]

If it's making hard drive noises it probably is still working. I have dozens of Macs from this time period and even older that all work fine.

Oops, didn't read that part. Damn me and my glancing at random threads that involve the word Performa. Just gets my motor running.

 

[4tified]

Oops, didn't read that part. Damn me and my glancing at random threads that involve the word Performa. Just gets my motor running.

As I had mentioned before, I did get it working with a pc monitor at one time...but you are right about getting the apple screen for it because I really can't know whether or not it still works unless I try it on one. Thanks for the help dpaanlka...I just didnt want to throw away my performa if I knew it worked.. that would be a tradgedy ;-)