Two different external lcd monitors won't work with dvi, is my mbp broken?

[rickcr]

I'm trying to get my BenQ FP91G+ monitor to work with my mac book pro. It works fine using the dvi cable in m windows xp machine. When I try to connect to my mbp using dvi, my mbp sees the monitor and I can change settings but the monitor stays black with an occasional "no input" message. I tried the same thing with another LCD monitor in the house (Princeton LCD19D) and the same problem.

My monitor does work though with the mbp if I switch to using a vga cable and then use the dvi adapter that came with the laptop.

Any ideas what could be wrong?

 

[synth3tik]

It could be that the monitors are DVI-D or digital. I would think though that this would prevent you from being able to change settings and the like. I does not seem to be the MBP as even using the VGA adapter would not work if the DVI port was bad. I would check what DVI you have on the monitor. I believe that the difference is in the line pin, If I remember right the DVI-D had a plus shaped pin.

 

[rickcr]

hmm thanks synth3tik, I think you have me on the right path... I looked at my horizontal line pin and noticed it was just straight with no pins around it... the dvi adapter that mac provided has a horizontal line pin (for lack of a better description) with four pins around it in a square.

Does this mine I just have an older type? I'm just a noob at this stuff. I don't mind using the adapter and set up with vga, I just don't want something to be broken on the mbp only to find out when I try to a demo on a projector in some confererence room

Thanks for any more info you have to offer.

 

[synth3tik]

It wouldn't really be older, just different. something done to just make us frustrated. there is 3 types of DVI there is combined DVI (DVI-I), digital DVI (DVI-D) and analog DVI (DVI-A), DVI-I or the DVI port on your MBP is the standard. I really haven't seen that many DVI-Ds. Basically it's like DVD-R and DVD+R. Just confusion for confusions sake.


DVI (standard)

DVI-D (not-so standard, mainly used in entertainment centers)

I also came across this web page that may help explain it better then me.
http://www.ramelectronics.net/html/DVI_info.html

I haven't seen any, but would think you could get a converter. Of course in this case you can use the VGA anyway..

 

[rickcr]

Hate to waste a forum post.. but still had to say Thanks synth3tik!

I was going to take me mac up to the apple store and you saved me a trip. I had no idea there were those different types of DVI outputs. Guess it was just a coincidence that both LCDs in my house had the DVD-D type (they were relatively cheap LCDs, if that matters.)

I'll look for an adapter none the less (just in case I need one in some conference room at some point).

 

[yippy]

The missing pins in the DVI-D port are just the analogue signal pins and only needed when using the DVI-> VGA adapter.

If the cables work connecting the monitor to your PC via DVI then there is no reason they shouldn't work when connected to the MacBook Pro. Make sure that the signal is within the monitors range, ie, a low enough resolution and refresh rate. If it is two high it can cause this behavior. Check this by checking the mirror displays box in the monitors preference pane.

 

[suneohair]

Hmmm. Well if you have a MBP which is 1440 by 900, the 19 is only 1280 x 1024. If you have it set to mirror, the MBP is trying to output its resolution which the LCD can't accept.

You need to set it to extended and manually define the resolution, although the MBP should get it automatically.

As someone else said, it has nothing to do with the cable. DVI by nature is digital, it does however carry an analogue signal for when you use it with a dvi-vga adapter.

 

[rickcr]

T
If the cables work connecting the monitor to your PC via DVI then there is no reason they shouldn't work when connected to the MacBook Pro. Make sure that the signal is within the monitors range, ie, a low enough resolution and refresh rate. If it is two high it can cause this behavior. Check this by checking the mirror displays box in the monitors preference pane.

I've messed with all kinds of settings even changing the resolution of the external lcd to 800x600 and having the refresh rate at 60. Still not working with the mbp with the dvi input.

 

[suneohair]

Well I suppose if your cable in acting as analog only, you would need the dvi-vga adapter...

 

[rickcr]

Well I suppose if your cable in acting as analog only, you would need the dvi-vga adapter...

So you are saying that even when I have the dvi cable from the monitor going to the dvi input on the video card of my windows machine (which works just fine), that it's truly not acting as digital and that's the problem? It seems odd that two home LCD monitors work with the dvi cable on windows but not on the mbp.

I'm at work now and have the laptop with me... I'll have to look around to see if someone here has an LCD monitor using dvi output that I can test with (might be difficult since these are older windows machines at work that I'm sure don't support dvi on the onboard video.)

 

[rickcr]

well sort of an update... went to best buy and decided to try the mbp hooking up to one of their lcd monitors using dvi. Only one pc was out connected with dvi so I tried that one. I really didn't have much luck with this lcd either, although I got a bit closer... when I set the lcd monitor rez to 800x600 I did see it show up - although it started scrolling so it wasn't much use.

Am I guessing you just have to work at getting the settings just right when using a dvi external display? This seems quite frustrating that I've tried 3 monitors now and haven't had much success. Is my experience common? (From what I can gather most people don't have any trouble. I'm wondering if maybe I have some setting screwed up some where.)

Thanks for any more advice/help.