External HP monitor won't display MacBook signal

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External HP monitor won't display MacBook signal

I have connected a HP LP2475w monitor to my MacBook using a Mini-DVI to VGA cable (white small) and the VGA to DVI cable (came with the monitor). When I connect the monitor comes to life, indicating that's there's something going on. But when the monitor scans for inputs, it doesn't find anything, and stays dark.

On my MacBook the screen is detected, and I can select resolutions and stuff. This operates like it normally does when I hook it up to an external monitor.

I'm sending the recommended signal to the external monitor (resolution 1920x1200 and 60Hz)

Is there any wat to fix this? (without buying a white miniDVI to DVI cable, and a DVI cable for the external monitor)

This setup works on my 19" DELL monitor, but not on my HP 24". (and the monitor works fine on my desktop, and other laptops)

Message was edited by: bruinsma

MacBook White, 2.4GHz Core2Duo / 2GB 667 MHz DDR2 SDRAM, Mac OS X (10.5.6)

Posted on Jun 9, 2009 4:57 AM

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Answer 1

BSteely

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Jun 9, 2009 7:30 AM in response to bruinsma

When you say the setup works with your Dell 19" monitor, do you mean it works using the same VGA/DVI cable you claim came with the HP? Or do you mean it works with the Dell using a VGA/VGA cable that came with the Dell?

A DVI/VGA cable like the kind that came with your HP is meant to be attached by DVI host-side, meaning to a computer with a DVI-I output port, and then the other end attached to the VGA input of a display. It typically won't work in reverse as you have it with the VGA side facing the host system.

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Answer 2

bruinsma Author

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Jun 10, 2009 1:52 AM in response to BSteely

When I use it on my old DELL monitor, I use the cable that came with the DELL monitor. It's special cable with a DVI connector on the monitor side, and a VGA connector OR a DVI connector on the other side (a split cable). The cable that came with the HP monitor is for connecting a VGA videooutput, to 1 of the 2 DVI ports on the monitor (both ports act the same, and there is no VGA port). This cable (the one of the HP monitor) works fine when I hook the HP monitor to a desktop with a VGA output....

But, if i'm correct; The output of my MacBook with the small white Mini-DVI -> VGA cable isn't different to the output of the VGA on a desktop (onboard VGA)
...?

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Answer 3

BSteely

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Jun 10, 2009 12:46 PM in response to bruinsma

OK, then I stand corrected about the use of the VGA/DVI cable that came with the HP. It is one of those rare monitors that has a DVI-I input. I wonder how HP handles the EDID identifier, in that case, which is meant to inform the system whether it should be driving digital or analog? My suspicion is the Mac is outputting DVI digital, which isn't going to reach the HP over a VGA connection.

I am afraid you will have to invest in an Apple Mini DVI to DVI adapter and DVI cable as you hoped you would not.

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Answer 4

Ramster

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Jun 10, 2009 11:56 PM in response to bruinsma

The same happens with the DVI Adapter. The HP monitor takes up to a minute sometimes until it displays, other times it is almost instantly.
Can anybody help?

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Answer 5

BSteely

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Jun 11, 2009 3:27 PM in response to Ramster

Does the HP have an "auto scan" function where it tries to find which input ports have an active signal? That could be why it sometimes takes a while to render an image. It could be scanning among all the inputs looking for signals.

Often times you can disable that kind of feature and switch it to be manually set to whatever input you like. Set if for DVI and see if that problem with the delay goes away. Good luck.

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