Pismo's screen connector - adding external monitor to internal header

6 replies [Last post]
Joined: Feb 12 2007
Posts: 2

Hi there,

I'm new to the Apple modding community, but having looked through these pages, I have to say I admire your work. And having a personal screwdriver set and a spare Mac, I couldn't resist for long.
First, some background on my systems. Besides my Pentium 4 Windows machine, I have two Pismo PowerBooks - one with a 400MHz G3 and my main computer with a 500MHz (very difficult to find). I bought the 400 back in May last year, and was so impressed that I hunted down one with a 500MHz processor to use as a donor to upgrade mine. I found one in November - it had the chip, 512MB RAM, a 20GB hard drive and an extra power lead. I got it cheap as the screen had met its maker - a long crack from corner to corner. The screen is pretty much dead, so I've decided to mod it.
What I want to create is essentially an iMac G3 TFT. In a nutshell, attaching the working logic board assembley, with hard drive, optical drive and processor, onto the back of a 15" LCD monitor. I've found a suitable candidate for a screen - it's a BenQ with a normal D-Sub 15-pin VGA lead.
The machine has survived being dismantled, and boots nicely. I can use the computer with an external monitor in Mirroring mode, but I would like to somehow attach the screen as the Primary display. Could I hack the Pismo's internal display connector to adapt it to a normal VGA port? I have the display ribbon from the original screen, and am confident with a soldering iron. If this is complicated to do, does anyone have a wiring diagram for the Pismo's display header that I could work from?
Failing this, could I disable the internal port and use the external VGA connector as the primary monitor? The screen has the same specs as the Pismo's internal screen.
Secondly, can I disable the battery system in the laptop? It seems trivial, but I'd like to eliminate the charger card from the machine as it's heavy and quite large. Also, this computer will be exclusively mains-operated. I'll hang the logic board assembly off the back of the screen and stick a custom enclosure over it, with the power supply integrated, thus a battery will be unnecessary.
Thirdly, I removed the screen inverter only to discover the sleep light is built onto the inverter card. Would it do any harm to reinstall the inverter exclusively for the sleep indicator? Or should I modify it so the inverter is disabled and if so, how?
Lastly, does anyone know of a wireless card I could install in the Airport card slot besides the original (they're damned hard to get a hold of)? I'd like this machine to be wireless-enabled, and am not fussed about speed (as long as the crad is not 802.11a-only).
Currently, the machine stands at this:
- Logic board assembly
- 400MHz G3 processor
- 128MB RAM
- 6GB Hard Drive with OS X 10.4.8 installed
- Modem card
- Charger card
- Airport card slot
- PRAM Battery
- Power switch
I also have the speakers, with the intention of mounting them inside the monitor if the integrated ones aren't up to spec. Everything listed above is still mounted in the lower case; I've removed the upper case and keyboard along with the screen, and it still boots. It will not boot if I take out the charger card.

Sorry for all the questions, but this is a project that I feel could have great potential - it'll be unique, and I'll have a desktop Mac to use.

Thanks in advance to everyone who posts,

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gobabushka's picture
Joined: Apr 26 2004
Posts: 494
im pretty sure that that woul

im pretty sure that that would fall into the holy grail catagory


"I reject your reality and substute my own!!!" -Adam Savage, MythBusters

Joined: Sep 21 2004
Posts: 74
I'm not positive, but...

here goes. If you want to boot that thing to an external display, which is what I gather, I believe all Apple laptops with an external display port will boot to that port if the lid is closed, and a keyboard and mouse are plugged in. Basically it seems like what you'd need to do to make that work on your Pismo would be to put a magnet on your reed switch (the thing that senses when the lid is open) in order to make it think it's still closed.

So far as removing the charge card, I THINK (but I may be wrong) it will boot without the card installed, you should certainly be able to boot without batteries installed.

So far as the inverter is concerned, you should be able to unplug the bulb and still have function of the sleep light, shouldn't be any harm in that.

Airport replacement I'm fuzzy on, if I recall, Lucent Wavelan silver cards or Orinoco Silver or Gold cards work natively as airport cards, just pop 'em into the cardbus slot.

Anyone want to correct me or back me up on any of this?

Joined: Feb 12 2007
Posts: 2
Re: I'm not positive, but...

Thanks for the vote of confidence!

"Basically it seems like what you'd need to do to make that work on your Pismo would be to put a magnet on your reed switch (the thing that senses when the lid is open) in order to make it think it's still closed."

Where is this 'reed switch?' If it's near the hard drive, I don't want to end up placing magnets near it. Alternatively, as this machine would most likely never have an internal screen again, should I just short out the switch instead of placng magnets inside it? Finally, would this mean that the external display becomes the primary and shows the boot-up screen?

The 'Book definitely will not boot with the charger card removed.

Thanks for the Airport-compatible cards - I'll look 'em up.

Thanks for the quick replies, and PLEASE wish me luck! I want to make a page about this when I finish!

themike's picture
Joined: Jul 21 2004
Posts: 455
I believe the reed switch is

I believe the reed switch is near the trackpad, somewhere along the top near the display latches.
Yes, instead of using a magnet to engage the reed switch, it would just be better to short it out, if you really are never going to use the computer outside of clamshell mode.


dream it, think it, feel it, be it

Joined: Jan 4 2005
Posts: 46
The reed switch for sleep in

The reed switch for sleep in the Pismos is in the screen module, next to the microphone (top right). Only the magnet is near the trackpad. The reed switch's sleep signal goes along the same cable from the logic board that the LCD was connected to.

Also, the Power Card (technically Power Board) is required for the Pismo to boot. I've tried without it and it doesn't work.

And, as someone else said, running an additional monitor from the internal display connection does fall under holy grail standing. Your only chance would be to get a display data cable from a pismo and try to plug that into a different LCD panel and use that.. you'd still need the inverter, etc. I'm not sure it'd be worth it for the extra inch of LCD size (and no extra resolution).


Macbook Pro/2.0ghz/256MBVRAM/1GB/120GB
Other macs: Powerbook G4/1.25ghz, iBook G4/1ghz, iMac G4/700mhz, PMG4 Cube/450mhz, iMac DV/500mhz, PMG4/400mhz, iMac/233mhz, PB1400cs/117mhz, 2 x Color Classic, Powerbook 100, Mac Portable, Mac512kE, Mac128k

Joined: Nov 4 2005
Posts: 43
Re: I'm not positive, but...

bin_jammin wrote:

Airport replacement I'm fuzzy on, if I recall, Lucent Wavelan silver cards or Orinoco Silver or Gold cards work natively as airport cards, just pop 'em into the cardbus slot.

My dell Truemobile 1150, which is a rebadged Orinoco, Works perfectly in the airport slot, It just doesn't fit under the keyboard. To use it in the external slot I had to run a freeware driver.