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Booting a PowerBook G4 without its top case?

iamMacPerson

iamMacPerson

macrumors 68040
Original poster
Jun 12, 2011
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I picked up a for parts PowerBook G4 the other day. It seems mostly complete minus the top case and the screws needed for the top case. I was wondering if there was a way to boot the machine without the top case? I ask because I want make sure the machine boots up and works OK before I go out and buy a top case.

Its the last model of the 15" PowerBook G4, A1138 DL SD Hi-Res 1.67GHz.

Thanks!
 
iamMacPerson said:
I picked up a for parts PowerBook G4 the other day. It seems mostly complete minus the top case and the screws needed for the top case. I was wondering if there was a way to boot the machine without the top case? I ask because I want make sure the machine boots up and works OK before I go out and buy a top case.

Its the last model of the 15" PowerBook G4, A1138 DL SD Hi-Res 1.67GHz.

Thanks!
Click to expand...
Not sure. I know that the trackpad ribbon cable also contains the linkage for the power button. So, if you don't have the cable plugged in, no boot when pressing the power button. No idea how you would jumper it to get it to boot without the cable being connected.
 
bizzle said:
http://tim.id.au/laptops/apple/powerbook/pbg4_15_dlsd.pdf

Page 6.
Click to expand...

Thanks. I finally found it but the machine won't boot. I put some RAM in I pulled from a MacBook (DDR2, 667) thinking maybe it needs RAM. Unfortunately even when I removed the RAM the machine still won't do a thing. The DC board does seem to have some problems. I can't move the connector too much before the light goes out, but it will eventually come on solid green but still no boot.

I'm going to let the machine sit for an hour or so and see what it does. I've seen some examples where I'll plug in a machine and it won't boot, but give it a few hours to put some juice in the charging circut and sometimes they'll boot.
 
I can see a few problem in what you are doing:

MacBook RAM is not compatible with the Powerbook G4. Using that RAM module will cause the system to fail a HW self-test, and thus, it won;t boot. Depending on your model, you need either PC133 or PC2700 (except for model Powerbook 21, 25, as that uses PC2-4200 RAM).

The wrong memory is very likely to be the culprit here. What model Powerbook is this?

I recall there being either a magnetic sensor, and possibly a light sensor that prevents it from booting when dismantled. You can fool either, but you first need to locate them. I recall that the magnetic sensor is used to detect the lid opening an closing, and it may prevent it from booting, or there may be a second sensor that prevents it from booting.

Check carefully for anything of this sort.

Most Powerbook models do not have RAM on the mainboard, so no-RAM is the same problem as bad-RAM, and wrong-RAM.

I believe that you must populate the bottom RAM-socket first: If you are only adding one module, populate the socket closest to the mainboard.
 
The correct way to puwer the system on, without a power button is to locate the power jumpers:

There are a pair of jumpers on the mainboard, that you need to bridge to start the system without the top cover. These are left of the centre horizontally, and near the centre vertically, on the mainboard, near the PMU reset. There are two pads, labled PWR_BTN. Bridge these with a copper wire, by touching one end of the copper wire to each pad, to start up the system.

The two jumpers have a horizontal, white line, separating them.

Please report on what happens when you bridge this connection, including any chimes, fan noise, screen illuminations, HDD spinning, flashing lights, or lack of any of these. Please note if the sleep light comes on when you start the system, and if it stays on, or dims. Please also report if the capslock light illuminates, by pressing the caps key when the unit is 'on'.

Tell me if the system makes any beeps or chimes, and if so, how many.

Does the KB backlight engage?

PC2-4200 is what the data sheet calls for, vs. PC2-5300. I have no way to tell what DIMM the OP is trying to use, but I would urge the use of correct memory if possible, to help thin out possible problems in a diagnostic flowchart.

The ALS is on on above the DC board, so you may want to try covering the light sensor with a piece of electrical tape for the present.
 
Update 3/5/2014: I finally got the machine booted. I had to jury-rig it to get it to boot without the top case.

You know, its always the little things that you think of last. I spent a good chunk of the day tearing the machine down to check every connection and couldn't find anything wrong. (I also re-did the thermal paste while in there, someone else already had not to long ago, but I did it again just in case) Threw in a spare SODIMM I pulled from an early MacBook, grabbed my power adapter, and still no go.

Went through all the troubleshooting online I could find. Nothing. Until I came across a thread with a similar issue and someone had asked the poster if he was using the right adapter. Suddenly, it clicked. I was using a 45W iBook adapter. :rolleyes: I grabbed the 60W I keep next to my bed, plugged it in, jumped the solder pads, and sure enough the sleep indicator came on and the speakers went "BOOOONNNNNNNGGGGGG".

Moral of the story, start small and work up on the troubleshooting scale. I'm still kicking myself.

DC board is still bad and will need replacing. Oh, thanks Apple or putting the DC jack on the sound board, one of the most expensive parts to replace.

By the way, I'm typing this on the machine with my USB Pro Keyboard. :D
 
Oh my, that is a slap in the face.

I use the 65W adapters for everything, as even having the 40-45W adapters can cause chaos, if you don't remember to check the version that you are using, before starting a project.

I hope that the rest of the information here was useful to you, and it is good that you have made some proper progress.
 
AmestrisXServe said:
Oh my, that is a slap in the face.

I use the 65W adapters for everything, as even having the 40-45W adapters can cause chaos, if you don't remember to check the version that you are using, before starting a project.

I hope that the rest of the information here was useful to you, and it is good that you have made some proper progress.
Click to expand...

Yeah, well, this was the first 15" PowerBook I bought (aside from the TiBook which works with the 45W just fine). I got the 65W power adapter with a lot of 2 iBooks G3's I bought off of craigslist. I probably would have just scrapped this PowerBook if I hadn't had the adapter to test it. I have 3 45W spread across the house incase I need to plug in and I have one of the PPC machines with me.

Guess its time to order some more 65W adapters.

Info was very helpful, thanks everyone! I was able to boot the machine without a top case so I tested it.
 
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