Need picture or pin-out of inverter cable from logic board 20" G4

Garrett,

switched the wires from the logic board. I didn't write down the configuration and now wish I had?

So when you say "switched the wires", you mean you pulled the wires out of the connector?

Can anyone give me a pic or cable configuration (or color) of the inverter cable? I looked at several PDF's but they are too grainy.

Which PDFs do you have? Service Manual?
Richard

garrett,

I have an after market inverter installed ($30 ebay) and hooked the power to the 12v and 5v from the PS. I do not get 12v from the logic board inverter connector 😟. I do however get .88-3.3v for brightness. I also get 5v on one pin and 3.3v on a few other pins.

So that works? It's just that you don't have brightness control?

I want to find the pin that turns the inverter on and off.

I would think that's a function of the PMU (guessing here)

I have tried one 3.3v pin and the 5v pin with no luck. The thing I fear as that with out the feedback from the PMW of the OEM inverter I will not get the lamps to actually shut off 😟 (unless I put the mac to sleep.

So here you're talking about the brightness control?

On a side note, I also found a burnt up inductor on the logic board.

So that was labeled "L" something?

I initillay thought this might have something to do with the lack of 12v from the logic board for the inverter.

Most likely. Did you check out the original inverter cable for shorts. Just had that in an iBook there was a tiny burn hole in the inverter cable and that took out a "F" fuse on the logic board. I didn't know the value of that either but this is the 2nd one I've seen and bridged it with a .25 A element from a 3AG the first has been working fine for over a year the second for two months.

However, in sleep I do not get the flashing light.

Not sure if that comes up the inverter cable??

Which with how an inductor works, I assume that is what it was for.

My understanding of how this works is that the sleep light is driven by the PMU or at least that's the way it used to be:

I have a small inductor on a PCI modem that I thought about replacing it with. But with out knowing the value of either inductor,

Well if it's SMT it can't be very large. Not like a thru board with a huge coil of wire.

I can live with out a flashing light but not with out a blown up 1.25ghz logic board 😉.

Well the logic board still works right? Just the inverter driver is kaput?
I'd try replacing that inductor since I'd suspect the value is not too critical and I wouldn't expect to see any LC timing devices on this board. Look for that short, however. It wouldn't have been a trivial failure that caused an inductor to blow. Unfortunately if a high amperage (relatively) component like an inductor blew there could very easily be a drive ic/transistor/array that's also toast.

So, if you can get me a pic of the inverter connector on the logic board side or cable color/order, that is all I need. And the service manual I have is for the 20" USB2.0 model that I have.

Yes that's what I have too but you kept the original order of the pins?
I had 2 17s taken apart here but the 20 is probably different.

Richard

Message was edited by: spudnuty

Hey G,

I have brightness control as I found that pin. However, the inverter takes 0-5v while the mac gives .88-3.3v and is bassackwards. No biggie though, it works just not full brightness or full dim.

Well you're way ahead of me on that. I've never gone that far into it.

Yes it was L103 (pic below). The inductor on the PCI modem is extremely close in size. it is surface mount and not thru-hole.

WOW! That blowed up GOOOOD!

I did check for continuity on all the wires. they are all ok even with twisting and such (check for shorts too).

Well given the state of that inductor I'd guess that if there was an original short that the short that caused this inductor to vaporize is also metal vapor.

The sleep light has its own wires. This is why I assume it is the inductor for the sleep light.

No I'm fairly confident that that pulsing is controled by PMU ( Actually a microprocessor PMU-99 ). Besides given the frequency of the sleep light pulse ~ .3 CPS the time constant for an LC circuit would make those components huge.

I fear replacing it since I do not know what cause it to blow up. I would hate to put a good inductor and then blow up the logic board

Good point. Also that trace I see leading to that inductor is huge comparitively. That's why I'd expect it to be in the inverter supply. A sleep light that required that size inverter would be around 10 W and would light up your whole room ;<)
So back to this possible short in the inverter cable. In a similar manner I didn't want to replace that fuse that had blown in the iBook for fear of killing the client's logic board but when I found the tiny burn hole in the inverter cable I felt more confident in the replacement. Also in that situation the cables tested continuity tests and tested no shorts to ground. However if I hadn't repaired the cable the client would have been moving the display around sometime in the future and the same thing would have happened. Since I had no clue as to the actual value of the fuse I might have had too large of a value in there and when that happened the inverter driver would have blown up too.
Richard

A cheese head Bears fan?
And are you the poster who's trying to run an iMac display jury rigged into something else?

Right now I have 12v power to inverter from the PSU connector on the logic board. I am using a 3.3v to turn the inverter on from the inverter connector on thelogic board as well as brightness control.

As it is right now everything works just fine. the only thing that bothers me is that the lamps do not "sleep" unless the computer does. I would like the lamps to go off when the monitor sleeps. That is all I am trying to do lol. I would assume that the pinouts on the 17" are probably different. But we could check 😀

img http://www.manfunk.com/pics/mine/inductorb.jpg[/img]

With that, this is my first mac (other then an apple II which I still have :)) and I am trying to figure out the OS. But that is a story for another time 😉

Thanks for your help,
g

Hey garrett,
Sorry I missed your posts but we were up in Madison.

until I accidentally ripped out the small ribon cable that goes to the side of the LCD glass 😟. Man was i bummed. I may try to fix it but that would be some intricate work.

You think that's repairable? Does it directly drive the matrix on the display? I've tried to repair those contacts that go directly to the LCD glass but have only succeeded in making it worse. Mostly on older PowerBooks.

There is one on there right now where the guy busted off the TMDS connector on the PCB.

Yes I think that could be a common problem. I had one detach from my wife's 800 G4 17". I'm wondering if this was a solder problem y'know when they moved to non lead solder. Anyway I pulled the board and sent it over here to Superior and they soldered the connector back on. I would have really been bummed if it was a 20".

I would have taken that off anyway and replace it with a direct solder DVI cable.

Really just for grins? That would be a rather large job I would think.

There has to be someone out there with a mac taken apart or with the goose neck assy with wires and connectors

Talk one of those guys w/ the 20"ers to take a picture for you. Pay him $20.
Richard

Garrett,

Madison? Do they have snow?

Nope totally dry.

It just bums me out, such a beautiful perfect screen

Yup I've never had luck repairing those

I won that auction for the G5 which comes complete with the case and stand. $70 shipped 🙂

Really? That's a gread deal. Wait what was wrong with it?

As for the pinout pic, $20? I suppose that is the route I just may have to go 😟

Well offer $5 to start.
Richard

Okay, so I just had to sign up for this forum when I saw it was garrettp who started this thread. A few Macrumors users and I referred to his pinout for the inverter for our own iMac LCD recycling project.

I'm in the middle of deciphering the inverter myself and have been wondering which wire of the yellow, orange, purple grouping varies voltage based on desired brightness. Is it known which wire carries this signal?

I take it the multiple inverters garrettp (alias used at electro-tech online) tried weren't working due to the inductor that fried?

My own logic board is toast from chipping the CPU die so I couldn't eavesdrop the signals while the machine was running.

I have entirely mapped out the TFT panel itself for a DVI connector, but lacking a way to hook up the inverter for this, I'm reluctant to take any major chances.

To translate: "Help?"