Broken TMDS cable on iMac G4.

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Level 1

6 points

Broken TMDS cable on iMac G4.

I just got a "new" used iMac G4 from a thrift store that I though just had a bad HD, but when I opened it up, I discovered that the TMDS cable that connects the supplies the data from the motherboard / video card to the monitor is broken inside.

The monitor turns on, and turns white, but obvious the data does not show up on the screen.

I want to restore this just because it is an amazing design. I know I can't use it for too much these days!

My question is, I have seen iMac G5 TMDS cables on eBay fairly cheap. Will this work on my G4? If not, how can I repair this?

Thanks!

Posted on May 26, 2017 8:43 PM

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Answer 1

K Shaffer

Level 8

36,016 points

May 30, 2017 12:05 PM in response to BluRose

A few online sources list the cable, one shows up as 'refurbished' from

welovemacs.com for a hefty $49.95 and states that is for 15-inch model.

A link to that page with a few numbers for reference:

imacg4-TMDS 15" iMac G4 Flat Panel TMDS Cable

So if you have seen the broken cable inside the iMac or helped it get

that way when getting inside, that is a good indication to replace one.

There are several wires and stuff inside these that can be easily broken.

Depending on which iMac G4 you have, some vendors may have stock

http://www.powerbookmedic.com/parts/M6498/ such as this listing.

Another source may be to contact wegenermedia.com as they've parts

and perform specialty repairs, logic board/graphic card resolders, etc.

Not sure which iMac G4 you have, as there were three by display size

and the cable may vary somewhat across the G4 iMac series. I've had

mostly (4) 17-inch 1.25GHz versions; + one 800MHz 17-inch dual boot.

The 20-inch model shared a few internal parts with the 17-inch 1.25GHz.

Good luck & happy computing! 🙂

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Answer 2

K Shaffer

Level 8

36,016 points

May 29, 2017 12:27 AM in response to BluRose

The cable from a G5 iMac would not be the correct part for an older iMac G4.

In fact the name of the part likely is different between these two models, too.

A repair company who specializes in or has access to parts inventories may

be worth looking into. Several things are going on very different in iMac G4

where the display has cables for data and power through the chrome arm

which supported the flat LCD panel. And if any of these has gone bad, the

effect may appear as something else.

There also is an inverter and other parts inside. I've seen where a few sites

have the original Service Manual (apple technical) for repair & take apart.

Because there were three or four different builds of iMac G4, there also are

more than two Service Manuals. And details are very important because of

how these come apart and have to be handled very carefully.

To have a replacement clock/pram battery (3.6V 1/2AA Lithium) on hand so

as to have something known-good to put in there where the old dead one is,

can help in troubleshooting. The computer may fail to work w/o good battery.

Good luck & happy computing! 🙂

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