68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Dead Powerbook 170 - Help about the resistor
Posted by: neo on 2019-08-30 13:56:55 Hello guys, this is my very first post and I really love this forum! So I recently got a Powerbook 170 that seems to be in great cosmetic condition for $20. The seller said that the computer won't power on. I took it home and tried to turn it on by pressing the power button and of course it did not work. I measured the output from the power adapter brick and it shows nothing so its dead. I then ordered a 7.5V power adapter and tried it on the powerbook but it still won't power on - the laptop looks utterly dead. To my surprise, the battery can still hold charge. I replaced the PRAM battery, tried to reset the battery management memory by holding both reset buttons for 30 seconds - none of them helped. So I completely torn it down and did a careful inspection on the PCB. I didn't really see any burned trace or noticeable blown capacitors. The fuse also measures okay. The only thing that I noticed abnormal is a resistor. It is R160 on the PCB. Definitely looks different from other resistors. It measures about 283ohms. Does anybody know the right resistance for it? If anybody can share a picture of it, that would be greatly appreciated.
Posted by: beachycove on 2019-08-30 17:10:50 Have you tried with no battery in?
Posted by: neo on 2019-08-30 17:15:07 Yes I did but it was the same. I kinda get lost now.
Posted by: techknight on 2019-09-13 12:43:22 Looks like a 220 ohm. But, I would have to double-check some of my parts boards to be sure. However, I would follow what circuitry that resistor goes to, if I were you. However, I fear the outcome will be grim at best. Resistors dont burn up like that unless something shorts and fails.
Posted by: Papichulo on 2019-09-15 16:57:56 You try it without the ram card in and is the gray interconnect? cable in right?
Posted by: neo on 2019-09-15 21:21:57 Looks like a 220 ohm. But, I would have to double-check some of my parts boards to be sure. However, I would follow what circuitry that resistor goes to, if I were you. However, I fear the outcome will be grim at best. Resistors dont burn up like that unless something shorts and fails. Thanks, I had the same concerns but my limited skills cannot support me to find the root cause. I actually went ahead and replaced it with a 1k ohm (before you posted this reply) and it didn't work.
Posted by: neo on 2019-09-15 21:24:24 You try it without the ram card in and is the gray interconnect? cable in right? I did, but nothing happened. I ended up replacing the guts with a working but missing hard drive PB 180 (which definitely has seen better days) and it runs okay. My PB170 looks a little weird because it now has two screen adjusting sliders rather than one :cheesy:
1