8100 power on / off

[imactheknife]

Ok, should have looked up 8100 before I bought this logic board. Was loaded with ram etc. it is now recapped but when power button is pressed it turns on then right back off. Psu is from my 8500 and is known to be good. I applied new thermal paste as well. Any ideas besides the 8100 being a pain in the arse?

 

[Phipli]

Ok, should have looked up 8100 before I bought this logic board. Was loaded with ram etc. it is now recapped but when power button is pressed it turns on then right back off. Psu is from my 8500 and is known to be good. I applied new thermal paste as well. Any ideas besides the 8100 being a pain in the arse?

It probably won't be your issue, but Apple says do not run an 8100 (or 7100) without something plugged into the PDS slot.

They're also old enough that some need recapping. (Not all of them yet, I haven't recapped my 8100/100).

Edit - I see you have recapped, sorry, didn't pay attention.

 

[Phipli]

PS you've posted in the wrong topic

 

[GRudolf94]

My 8100 board would chime with an empty PDS.

How soon is "right back off"? A couple seconds? A second? Half a second? Just a twitch of the fan?

 

[imactheknife]

My 8100 board would chime with an empty PDS.

How soon is "right back off"? A couple seconds? A second? Half a second? Just a twitch of the fan?

It turns in, fan spins for a second then off. No chime. Not sure enough time to chime

 

[Phipli]

It turns in, fan spins for a second then off. No chime. Not sure enough time to chime

What happens if you keep the power button held down for, say, ten seconds. Does the fan still stop? Or does it go until after you release.

 

[imactheknife]

What happens if you keep the power button held down for, say, ten seconds. Does the fan still stop? Or does it go until after you release.

I think it stays going but will have to try again to see. Have it off to the side for other projects. Will try later tonight hopefully

 

[Phipli]

I think it stays going but will have to try again to see. Have it off to the side for other projects. Will try later tonight hopefully

Sounds like it isn't latching, likely a broken trace, could be a dry solder joint, possibly a bad chip, but it usually isn't. There is a description of how the soft power works on older macs here :

restoring a battery-bombed IIcx

How much alcohol does that require? (Consults slide rule...) I think it would need more than a whole 16 ounce bottle to fill a tub to a depth of a few mm for submersion. A lot :) I try to recycle the alcohol as much as I can. Got used to recycling for 3d resin printing. I keep my general...

68kmla.org

You probably won't need it, in fact I'd say it is more distracting than useful as you're probably just looking for a crusty trace near the battery, U46 or possibly U52, but find attached 8100/110 schematics. Page 16 is of interest.