(future mod) The incredible Powerbook G5 17"

[Rikintosh]

You didn't read it wrong, I actually said G5. I am studying and designing a modification to transform a common 17 "G4 into a Powerbook G5. I will use the motherboard and some other components of any iMac G5. Of course the notebook will be thick and heavy, but that is not a problem for It may seem like a stupid idea, but I'm doing it as a hobby.

Perhaps it will be thinner than in the image above.

I chose the iMac g5 (instead of a powermac) because the imac's motherboard is the thinnest G5 system I've found. At first I will not include a battery in the system, I will consent and make it work perfectly, and only when I reach this goal, I will think of a battery system. Even though it will be so big and heavy that it may not even be possible to use it in a place other than a table.

I will basically adapt the keyboard and trackpad to USB, and the display to VGA (with those aliexpress cards), later I will make an aluminum box, which will be the base, where the keyboard and screen will be attached. The connectors on the motherboard will be transferred to the side of the notebook (using wires and solder, or small male / female cables connected to the ports). As for the heat, after a few weeks of research, I discovered that the processor is not the villain. The problem is in the heatsinks that apple uses, a polishing with sandpaper solved the problem (I already did the test, I lowered the temperature of my powerbook g4 by 10 degrees)

The system will draw air from the front of the laptop, and blow out hot air from behind (behind the display) similar to what we see in today's gaming laptops.


In the coming months I will start to buy the necessary parts.

 

[davisdelo]

Best of luck, it would be pretty cool to see something come out of these good intentions. My only suggestion would be to down-clock the processor, ram and gpu to mitigate the heat. Even if you ended up with something that performed with the equivilance of a last-gen G4 Powerbook, it would be neat to see developed.

 

[weckart]

You might be better off scrapping the whole laptop thing and aiming for a pizza box desktop - a sort of Mac Midi. Given the cooling needed, the laptop thing isn't going to work with the PowerBook screens available unless you are going to repurpose the actual iMac G5 screens.

 

[Amethyst1]

and the display to VGA

Using VGA for an LCD is the most pointless thing ever.

 

[weckart]

Using VGA for an LCD is the most pointless thing ever.

I assume he meant using the inbuilt external mini-VGA port. That only mirrors what is on screen so I don't know if it will work without an internal display.

 

[Amethyst1]

I assume he meant using the inbuilt external mini-VGA port.

So did I - I'd try using the internal LVDS to have a digital signal.

 

[Amethyst1]

That only mirrors what is on screen so I don't know if it will work without an internal display.

Years ago I came across an imac g5 that had been converted to a tower and iirc the vga out worked without the internal lcd. Can't find the link right now though.

 

[Amethyst1]

Years ago I came across an imac g5 that had been converted to a tower

And here it is (no pics sadly) but confirms VGA works without the LCD.

Franken Mac G5

 

[Rikintosh]

Using VGA for an LCD is the most pointless thing ever.

I was referring to an interface. The voltages and pinouts used on the imac screen are different, the imac screen is too thick for the powerbook display housing

Best of luck, it would be pretty cool to see something come out of these good intentions. My only suggestion would be to down-clock the processor, ram and gpu to mitigate the heat. Even if you ended up with something that performed with the equivilance of a last-gen G4 Powerbook, it would be neat to see developed.

There is no need, as I said, the processor tdp is low, the real heat problem is in the quality of the heatsink material that apple uses. (It's like using a heatsink without a thermal compound). The G5 "single" processor has a TDP of 38 ~ 43w

Polishing the heatsink, and with the motherboard outside the case, it is possible to use it even without a fan.

You might be better off scrapping the whole laptop thing and aiming for a pizza box desktop - a sort of Mac Midi. Given the cooling needed, the laptop thing isn't going to work with the PowerBook screens available unless you are going to repurpose the actual iMac G5 screens.

But the point is that I want to continue where Apple left off, a G5 laptop, I'm not doing it for functionality, I'm doing it as a work of art

 

[z970]

the real heat problem is in the quality of the heatsink material that apple uses. (It's like using a heatsink without a thermal compound). The G5 "single" processor has a TDP of 38 ~ 43w

Polishing the heatsink, and with the motherboard outside the case, it is possible to use it even without a fan.

This is very interesting news to me. Would you provide a little more information about this? Does this apply to all heatsinks, or does Apple just skimp on costs and use special mixed-alloy sinks? And do new heatsinks need to have this done, or is it just one of the perks of retro computing (perhaps similar to the capacitor plague)?

And the sink contact surfaces are (mostly) seamlessly flat - sanding them would create micro grooves on that surface. Does this increase the thermal transfer ability because instead of a mostly flat surface with minimal surface area to grab hold of, the paste now needs to fill these grooves, creating a larger surface area that heat can transfer into via the paste? And if this is so, then that would mean that the deeper the grove is, the more surface area of transfer the paste can utilize - similar in practice to the concept of heatsink fins and ambient air. And do you know if this also works with thermal pads as well as paste?

Interesting news indeed...

 

[weckart]

And the sink contact surfaces are (mostly) seamlessly flat - sanding them would create micro grooves on that surface.

I believe bunnspecial made a post here about having done that. If I remember correctly, the process was called lapping and it seemed akin to microgrinding/polishing a lens. Quite laborious but removed all the pits and tiny imperfections on the surface that prevented a good contact between the CPU and the heatsink.

There's a guide to it here:

how-to-lap-a-heatsink

 

[Rikintosh]

This is very interesting news to me. Would you provide a little more information about this? Does this apply to all heatsinks, or does Apple just skimp on costs and use special mixed-alloy sinks? And do new heatsinks need to have this done, or is it just one of the perks of retro computing (perhaps similar to the capacitor plague)?

And the sink contact surfaces are (mostly) seamlessly flat - sanding them would create micro grooves on that surface. Does this increase the thermal transfer ability because instead of a mostly flat surface with minimal surface area to grab hold of, the paste now needs to fill these grooves, creating a larger surface area that heat can transfer into via the paste? And if this is so, then that would mean that the deeper the grove is, the more surface area of transfer the paste can utilize - similar in practice to the concept of heatsink fins and ambient air. And do you know if this also works with thermal pads as well as paste?

Interesting news indeed...

It is not sanding the way you imagine. It is a polishing using sandpaper (to polish you need something abrasive to remove material) it is also possible to do with specific paste compounds for this, but sandpaper is easy to find.

With the naked eye, you do not notice the grooves, you need special equipment to see them (microscopic level), the problem extends for many, even models of other brands, because apple (and other brands) are not manufacturers of all parts, for example, an engineer designs the shape of the heatsink to fit the machine, then apple passes the design on to a chinese manufacturer that has metal casting, and he manufactures them and sends them to apple / foxconn to assemble on the machines.

guide: https://www.brandonfoltz.com/2013/02/lapping-your-cpu-a-handy-guide/


Here is a list of ppc TDPs

G4 7455 (180 nm) 1.0 GHz: Typical 15 Watts, Max 22 Watts
G4 7455 (180 nm) 1.33 GHz: Typical 30 Watts, Max 40 Watts
G4 7447A (130 nm) at 1.42 GHz: Typical 21 Watts, Max 30 Watts
G5 970 (130 nm) 1.8 GHz: Typical 51 W, Max ??? (est. 90-100)
G5 970FX (90 nm) 2.0 GHz: Typical 24.5 W, Max ??? (est. < 50)
G5 970FX (90 nm) 2.5 GHz: Typical 50 W, Max ??? (est. 90-100)

 

[Rikintosh]

These are images taken by a device that can show the grooves (like a microscope), depending on the material of the heatsink, the grooves are better or worse.

See, the polishing doesn't scratch, on the contrary, the surface becomes so smooth, that it starts to reflect better, it practically becomes a mirror


There are more technical things that I could spend all afternoon writing, but I think I would be getting off the main subject a lot. The point is that polishing is never too much, there are only benefits, this is well known in the overclocker environment (to help lower temperatures, and achieve higher clocks).


Of course, there is one more thing you can do to help with cooling: Apple engineers and designers were very concerned with appearance, and little with efficiency. If you dare, disassemble your powerbook or imac, and make a big hole in the place where the fan is, this is another big problem for macs, they recirculate hot air, there is not a good ventilation of fresh air inside in most models ( because of the beautiful design), you make the holes the size of the fan's helix, and close them by placing any metal screen (tip use loudspeaker screens, like the ones we see in cars from the 80s and 90s). After doing this, you will notice that your machine will work fresh and in complete silence.

Or if you are patient and looking for a more beautiful result:

These tips are very useful if you have a 1.67Ghz powerbook and want to overclock. There was a guy who managed to reach 2.0 Ghz

 

[z970]

@Rikintosh I see - so it is the opposite of what I thought. I will definitely use this 'lapping' technique next time I get the chance!

Man, I love learning!