1680x1050 stopped working after update.

I have been using a 22" 1680x1050 monitor connected via VGA->mini-DVI without problem.

Then I restarted to apply some updates and now 1680x1050 simply will not work. The the resolution is on the list but it sends a bad signal to the monitor.

I tested the cable and monitor with my PC and the monitor still works perfectly.

All other resolutions work fine (except for the quality issues from using a non-native resolution) including 1600x1200.

Any thoughts?

I have been planning on doing a clean install of snow leopard to a 640 GB hard drive I bought on black friday.

With the clean install 1680x1050 worked fine .. until my first reboot at which point it has the same problem. Bad signal at 1680x1050 ... all other resolutions work fine.

Can you open up System Preferences > Displays > and then choose a different Hertz setting? How about a different resolution altogether. And of course the old, unplug it, restart and then plug it back in technique.

Give us the specs of your PC and monitor.

True Bassist said:

...

Give us the specs of your PC and monitor.

Click to expand...

And your Mac - prefer the make and model # of the monitor.

I have an 13" Aluminum 2.0ghz C2D MacBook (Model Identifier MacBook5,1) NVIDIA GeForce 9400M Graphics card.

The Monitor is a Acer P224Wbk 22" with a native resolution of 1680x1050. I am using VGA via a KVM switch and Mini Display Port Adapter.

1680x1050@60hz is one of my options but the monitor rejects it saying no signal. (With or Without the KVM)

My XP Desktop has no problem connecting to the same monitor via the same cable at 1680x1050@60hz.

The Mac book has no problem connecting to a 24" Dell monitor via the same setup (including the KVM) at 1920x1080.

The odd thing is that when I first connected it, it worked find at 1680x1050 for several days and it wasn't until the first restart that it ceased to work at that resolution.

When I did a clean install of Snow Leopard again it worked fine at that resolution until I restarted. Thereafter that resolution ceased to function.

All other refresh rate options are grayed out, I can only chose 60hz.

I forgot to mention that it works fine at other resolutions including 1600x1200, the monitor even does a fairly decent job of scaling.

Still digging - I assume you have tried the Detect Display button in Displays preferences.


edit:
Need to take the KVM switch out of the picture completely until it's sorted.

The Acer user manual stresses the monitor should be turned on prior to the computer.

That's all I've got.

Argh - I can't find anything anywhere - suggest you check out bobtomay's advice on this one. Turning the monitor on prior to the MB could be your saving grace.

One more thing, the mini-display port to VGA adapter has had a firmware update - have you installed that? It's available here.


Suggest going straight to the monitor without the KVM just in case there is an issue with it passing EDID info. Turn on the Acer, then boot the MB.
Make sure the MB is plugged into power, not just running on battery.
Then go grab the update.

The very first thing I did was take the KVM out of the picture
The next thing I will do is install the firmware update for the adapter

It worked again briefly when I migrated my old user account. Both OSX and the montior reported the resolution as 1680x1050@60hz and it worked fine until the first restart then stopped.

My guess is that there is some custom something for this monitor that OSX installs after rebooting which has bad setting for 1680x1050@60hz.

?? Not sure on that count, but that firmware update supposedly dealt specifically with some resolutions not being available and/or displaying a black screen.