On switch? (7500/100)

[salmoneous]

I haven't used a Mac in over 20 years, so assume I know absolutely nothing. And to prove how little I know, they may be the most nubie question ever:

Just bought a Power Mac 7500/100 off ebay (for next to nothing.) The seller didn't do a decent job of packing. There was obviously some damage to the case when I opened his box.. little bits of twisted and/or broker plastic here and there. First thing I did was get the top of the case off the computer and gently poke around. I don't see any obvious damage to the actual components. No lose wires or anything. Maybe it was just damage to the case and the computer is fine??? So now it's time to test it.

I plug it in.... and I realize exactly how much I don't know what I'm doing. I can't find any obvious power buttons. Did these computers have power buttons that I can't find? Or was there some other way to turn them on and off?

There's a hole in the lower left corner on the front of the case that seems like it should be for a power button... but I don't see anything on the computer itself that corresponds with that hole.

What am I missing here?

 

[waynestewart]

A couple inches behind that hole in the front of the case is a button on the motherboard that can be used to start the 7500. If you have an ADB keyboard connected then there's a power key on the keyboard. It's position varies depending on the keyboard but it usually has a triangle on it.

 

[Trash80toHP_Mini]

Be glad your first acquisition wasn't in the 610/6100 series, the idiotic power switch on those things look for all the world like a floppy eject button. :

 

[salmoneous]

Thanks guys. Once I knew what I was looking for, I realized the problem. There's supposed to be a little plastic thing that goes over the power button (as shown in this picture - http://www.vectronicsappleworld.com/collection/articlepics/pm720075/snap32.jpg). Pretty sure I saw the broken pieces of that in the debris I cleaned out. But knowing that's the power button, I was about to manually operate the button.

It now power's up. Or, at least the power light comes on, the fan spins, as does the hard drive. Should there be POST beeps, or is that just as PC thing?

At the moment, there doesn't seem to be any video signal headed out to the monitor.. and the power button on the keyboard (thanks for the tip about the triangle) doesn't seem to do anything. But I haven't played around with it much... much just be a poor cable or something.

Off to play around some more...

Sal

 

[LCGuy]

It should make a boot chime, but no beeps, a "bong" sound is the Mac equivalent to the beep that a PC makes when it passes the POST.

 

[phreakout]

Salmoneous,

I, too, have a 7500. Allow me to help.

Obviously as noted earlier, you can use the keyboard to power it up. Depending on the model keyboard, there will be a single, large key with an odd shaped triangle pointing to the left. If you have an Apple Keyboard II (M0487), it's the large button next to the color Apple logo. If it's an Apple Keyboard I (M0116), again, it'll be the largest one at the top. Apple Extended Keyboard (M0115) will have the key at the top right corner, near the Caps Lock, Num Lock and Scroll Lock lights.

Regarding the power but no action, I've had this happen before and it occurs when the power management unit is corrupted, usually due to a dead or dying PRAM battery. Check that battery with a voltmeter; it should read 3.67 Volts DC or better. If less than 3.64, I would just replace it.

If it still doesn't startup, try powering up without the battery. If still nothing, I have a last resort:

1.) Unplug the 7500.

2.) Remove all the PCI cards installed (if there are any).

3.) Remove the RAM.

4.) Remove the VRAM.

5.) Remove the CPU card.

6.) Add power and turn it on for about 5 seconds, then shut it off.

7.) Add the CPU card, then step 6. If you hear what sounds like glass breaking from the internal speaker, you're almost home free.

8.) Add the VRAM, then step 6.

9.) Add the RAM, then step 6.

By the time you try steps 8 or 9, it should produce a normal startup tone.

10.) Add the PCI cards, then step 6.

The above procedure is kind of like giving the 7500 a defibrillator; step 7 indicates that the ROMs are alive. Once VRAM and RAM are added back in, now the 7500 can do something useful. Give it try and let me know how it works for you.

73s de Phreakout. :rambo: