reuse G4 (iLamp) LCD

14 replies [Last post]
Offline
Joined: May 31 2006
Posts: 3

What is the pin layout of the TMDS connector of a iMac G4?

The mainboard say J10, and the cable say it is TMDS.

It is a connector of 21 pins, the small row is 10 pins, the other have 11 pins.

Can I connect a convertor and use it for a Mac Mini?

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Dr. Webster's picture
Offline
Joined: Dec 19 2003
Posts: 1630
[url]http://www.applefritter.
__________________

Applefritter Admin

iamdigitalman's picture
Offline
Joined: Mar 2 2004
Posts: 629
[url=http://www.devhardware.c

this should help. first reply sums it up. you cant. at least not easily. your welcome to try, but your on your own. as Dr. Webster posted, we have a section about that very thing. if you achieve it, you willl have attained the Holy Grail

here's a pic for some insperation:

good luck.

-digital Wink

Offline
Joined: May 31 2006
Posts: 3
It is not a notebook, it is a

It is not a notebook, it is a iMac G4 flatpanel.

The cable say TMDS so I suspect it talks some kinds of DVI protocol. So I want to ask more before giveup.

Eudimorphodon's picture
Offline
Joined: Dec 21 2003
Posts: 1139
Eh. Maybe.

kentsin wrote:

It is not a notebook, it is a iMac G4 flatpanel.

The cable say TMDS so I suspect it talks some kinds of DVI protocol. So I want to ask more before giveup.

TMDS is the signaling protocol used over DVI, so, well, it's possible you might be able to drive the thing from a DVI port. One "gotchya" I can think of so far. The hardware documentation for the G4 iMacs:

http://developer.apple.com/documentation/Hardware/hardware2.html

indicates that an on-board scaler on the motherboard video chipset is used to allow the flat panel to display non-native resolutions. Most DVI monitors have a built-in scaler and scan rate converter for that. Thus... if I had to hazard a guess I'd say that *if* the LCD is driven by DVI compatible TMDS signalling it's using a really brain-dead TMDS->LVDS driver board in the LCD assembly which is missing most of the features you'd need to make "easy" to use it with a standard DVI monitor port. (There would be no reason for it to have a scaler, as noted, nor would it necessarily need things like a VESA DDC channel for identification and power control, etc, etc.) Thus it may technically "work", but you'll have to hard-program the video card in the machine you're driving it with to output a suitable video mode for it. ("Suitable" meaning the one fixed resolution the panel natively supports.")

If you can find the pinout for that connector it might be an interesting experiment, granted.

--Peace

Offline
Joined: May 31 2006
Posts: 3
What if I got a board with LV

What if I got a board with LVDS adapter? Can I connect it?

Offline
Joined: Aug 15 2006
Posts: 3
What if you drive the screen

What if you drive the screen at it's native resolution only?
I'm planning a similar project with my 20" iMac G4, hoping to get a 15" to play with first.
http://forums.macrumors.com/showthread.php?p=2721274

Otherwise, http://www.ieci.com.au/products/Product_Page2.asp?Product_ID=3540
and
http://www.impulse-corp.co.uk/Industrial%20Computer%20Boards/Product%20Pages/peripheral_display_PCM-3538R.htm
or similar might be needed. And I don't fancy that.

Offline
Joined: Dec 20 2003
Posts: 7
pinout of internal iMac G4 screen connector

half post removed and completed in the next comment. sorry.

admins: please remove this post.

__________________

Half quad , a few macs from before 1992, NeXTStation Turbo Color 96/2Gb Nextstep 3.3

Offline
Joined: Dec 20 2003
Posts: 7
pinout of internal iMac G4 screen connector

i have taken apart my broken 15" screen and it turns out to be a samsung LTM150xl-01p.

then i took that apart as well and found the interface chip: a silicon image si I151ACT100 and with that i finally got a pinout for the connector on the motherboard.

the connector on the motherboard has 21 pins, but uses only 19 of them. the cable is 1on1 on both sides, except for the connector formfactor. if you look at the motherboard side, pin 1 is on the opposite side from mthe cable, counting towards the cable. the flat connector on then screen side counts from right to left if you hold the cable with the connector facing up, as it is connected to the screen.

1 green Vcc
2 blue Vcc
3 brown/black GND
4 red/black GND
5 black RX2+
6 red RX2-
7 clear RX2 shield
8 Brown RX1+
9 Orange RX1-
10 clear RX1 shield
11 yellow RX0+
12 green RX0-
13 clear RX0 shield
14 Blue RXC+
15 White RXC-
16 clear RXC shield
17 purple ?
18 -
19 grey ?
20 pink ?
21 -

I think 17, 19 and 20 have something to do with either DCC or just a tie to gnd or Vcc to identify the screen to the motherboard. i have to dig up my scope to be sure.

Thinking about it, the screen seems to me regular, ie not specially build for apple, so it could be that it is a fixed resolution with a single resolution DCC

I have not measured Vcc yet, but i suspect it to be 5V.

__________________

Half quad , a few macs from before 1992, NeXTStation Turbo Color 96/2Gb Nextstep 3.3

Offline
Joined: Feb 18 2007
Posts: 1
We've been discussing the sam

We've been discussing the same thing over at:
http://forums.macrumors.com/showthread.php?t=224698&page=3

It's an intriguing subject for those of us with broken G4 iMacs on our hands. Keep up the investigation!

Offline
Joined: Dec 20 2003
Posts: 7
Re: pinout of internal iMac G4 screen connector

macsimski wrote:

I have not measured Vcc yet, but i suspect it to be 5V.

it turns out to be 3.3 volt for the electronics. the lamps get their power via another connector running on both 3.3 and 12 volt. 12v olt for the power, 3.3 for the controller electronics. Its a pity that it is impossible to completely blackout the screen, but only dim it to 25 percent. otherwise it could be a nice lightsource in stead of the screen. Make it a real iLamp Wink

the three other lines on the video connector remain a mystery to me, as the internal video chip does not seem to use DCC at all. If i disconnect the screen and attach a regular vga screen, the resolution options do not change. Sad

Reading a post somewhere about using the external screen as a extended desktop confirms that this is not possible with the 700 and 800 Mhz 15" imac; cripled video hardware...

you could have more luck with a 17" here. I am curious about the internal video connector on those machines. there should be DCC signals there because there was a 15" and 20" option for those macs.

__________________

Half quad , a few macs from before 1992, NeXTStation Turbo Color 96/2Gb Nextstep 3.3

Offline
Joined: Aug 15 2006
Posts: 3
Ok, it really is looking like

Ok, it really is looking like the best approach is to throw out the (beautiful, well-lit, dead-pixel-free 20") LCD that came with it, and buy one whose dimensions match the original exactly. I've seen pictures of a cracked-open arm, and there appears to be room for cables, though you'd have to strip them, and I don't know where you'd out the power converter from any monitors currently available..

I bought a Macbook recently, so I'm going to compromise on some sort of remote control setup (iMac as screen for MB) for now, but I'm sure when iLamp's useful life has come to an end, I'll gut her and put in Mini (or Nano by then!) innards.
I love lamp.

Jon's picture
Jon
Offline
Joined: Dec 20 2003
Posts: 2804
Zombie thread a bit, but the

Zombie thread a bit, but the best approach would be to sell off the still good LCD panel and stick in another monitor, assuming that one wants to do all the warranty voiding work to do it over just using the new LCD monitor as-is.

__________________

I am not in this world to live up to other people's expectations, nor do I feel that the world must live up to mine. - Fritz Perls

Offline
Joined: Aug 15 2006
Posts: 3
a new use!

Hey guys,

this thread doesn't appear to have dug up the answers to the key difficulties we were having; namely the pin-out for the gorgeous LCD screen, but it's titled Reuse G4 (iLamp), and after 2 years of trying to resurrect my G4, I've thought of an appropriate use for it..
It's still a piece of gorgeous design, so I don't want to sell or destroy it in any way, but it's now too slow to even playback and browse my media (with Tiger), so I'm going to turn it into the centrepiece of my new MAME cabinet!
I've bought a Tankstick from X-Arcade, downloaded 18Gb of ROMs and I'm going to play retro games using MacMame. The Apple Pro speakers sticking out of the cabinet, I can see it now. Might even put in some sort of jukebox, as it still has the master copy of all my music on it.
I'll post pictures when it's done.

Offline
Joined: Dec 12 2008
Posts: 1
Another attempt at this (hope others out there havn't given up)

I'm in the process of trying to convert a iMac G4 I picked up on ebay into a monitor. I tried a different approach which failed, so I am in the process of replacing the LCD with a different one. But now I have a new problem. The flex cable used on the new LCD isn't nearly long enough to reach down the length of the neck and connect in the base of the enclosure. I'm hoping someone here knows where one could get extra long ribbon cable, or know or have experience in extending a ribbon cable (I've heard soldering isn't a good idea) I'm hoping I can get this wrapped up in the next month or so based on free time, so if anyone has any suggestions I'd greatly appreciate it!!