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7100 no video

trag

Well-known member
Got a 7100 that won't output video.

I have the same problem with 6100.

So, my 7100/80 just started exhibiting the same behavior

Yeah, I’m not sure why Apple engineered the x100 PowerMacs to require a good PRAM battery just to boot. But it’s definitely a thing as I’ve run into it on all my boards myself. I don’t have a video card I can try on one to experiment with.


The most common cause of this issue is that the heat sink grease on the CPU has turned to chalk, and needs to be thoroughly cleaned and replaced. I didn't see it mentioned in Josh's list of things he tried, although with all the other board maintenance he did I'd be surprised if he didn't replace the heat sink grease.

The PPC601 overheats before it can finish booting up. If you're "lucky" enough to be using the machine as this problem begins, first you'll see some video artifacts. Then you'll start to get random freezes. Then the machine will only stay 'on' for a short time. And finally, apparently, no boot at all.

Of course, it's also possible that there is a hardware problem with the chips/circuitry. But the heat sink grease is where I would start.

Only the 6100 requires the PRAM battery to start up. It's a function of the type of power supply used.

And cracked PPC601s are not uncommon. Replacing that chip is a pain the neck, but I think Kai R. obtained a largish supply of PPC601 chips a while back. There were two different pinouts/supply voltage versions and I'm not sure which he got. One set is commonly in the 6100/7100 and hte 8100/80 and hte other type is in the 100 MHz and faster machines. I'm not sure about the 7200/90.
 

macuserman

Well-known member
The most common cause of this issue is that the heat sink grease on the CPU has turned to chalk, and needs to be thoroughly cleaned and replaced. I didn't see it mentioned in Josh's list of things he tried, although with all the other board maintenance he did I'd be surprised if he didn't replace the heat sink grease.

The PPC601 overheats before it can finish booting up. If you're "lucky" enough to be using the machine as this problem begins, first you'll see some video artifacts. Then you'll start to get random freezes. Then the machine will only stay 'on' for a short time. And finally, apparently, no boot at all.

Of course, it's also possible that there is a hardware problem with the chips/circuitry. But the heat sink grease is where I would start.

Only the 6100 requires the PRAM battery to start up. It's a function of the type of power supply used.

And cracked PPC601s are not uncommon. Replacing that chip is a pain the neck, but I think Kai R. obtained a largish supply of PPC601 chips a while back. There were two different pinouts/supply voltage versions and I'm not sure which he got. One set is commonly in the 6100/7100 and hte 8100/80 and hte other type is in the 100 MHz and faster machines. I'm not sure about the 7200/90.
Thanks for the tip, I just pulled my 7100 out of the mothballs after a month or so of not using it and it now chimes but doesn't give me video either. Was working fine before storing and wasn't that awful long ago.
 
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