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Dead DVI -- is it likely to be the dock or the laptop?

Posted: Sat Sep 01, 2007 8:53 pm
by ark
T60 with Radeon 1400, advanced dock (not mini dock). Built-in display works fine. When I try to drive an external monitor from the DVI port on the dock, it is completely dead.

It worked until today. This evening, I tried a longer cable and got a completely weird false-color display. I put the original cable back and there was no image at all. I tried the same monitor with the same cable on another computer and it worked fine. I tried the Thinkpad with this monitor and another monitor -- it detects that the monitor is there but doesn't send an image. The analog port on the docking station works fine.

I can't try connecting the laptop directly to the monitor because the laptop has no DVI port -- it's just in the dock. So, does the dock just pass DVI signals through from the display chip, or does it have its own frame buffer, etc. In other words, is it worth trying to get the dock repaired or replaced before trying to repair the laptop?

Both the dock and laptop are still under warranty.

Posted: Sat Sep 01, 2007 9:16 pm
by Harryc
The DVI-D is a pass-through port.
http://www.thinkwiki.org/wiki/ThinkPad_Advanced_Dock

I'd guess that the Thinkpad is the problem. Why not send them both in? Also, I'd toss that longer cable if it were me. You didn't plug it in while the laptop was powered up did you?

Posted: Sat Sep 01, 2007 9:20 pm
by ark
I'd rather not have to do without the laptop for a week if the problem turns out to be the docking station. But if the dock is just a pass-through, it doesn't seem likely that the dock will be the problem.

Anyway...I called tech support and they would rather send me a new docking station before trying to repair the laptop. They seem to think it might be a problem with the DVI connector in the docking station.

Posted: Sat Sep 01, 2007 11:04 pm
by ark
One more thing. Maybe this showed more guts than brains, but I tried that cable with a different computer. Again the colors on the screen were completely scrambled. Needless to say I shut that computer off quickly and put everything back the way it was. Fortunately this computer survived without ill effects.

So maybe there is something about this cable that scrambles video cards, like a short between the power lead and one of the others. Either way, the cable is going back to the vendor, I'm getting a new docking station, and if that doesn't fix the problem, the laptop goes back to EZServ.

Posted: Sun Sep 02, 2007 7:07 am
by Harryc
ark wrote:One more thing. Maybe this showed more guts than brains...
We finally agree on something you did :).

Posted: Sat Sep 08, 2007 7:40 am
by ark
The new docking station arrived, and as expected it didn't help anything. So the laptop goes back for repair on Monday. I'll keep you posted.

Posted: Wed Sep 12, 2007 1:04 pm
by ark
I promised an update; here it is:

The laptop came back today, not fixed. The partially legible note said that the problem was that the BIOS had been set incorrectly -- it needs to be set to LCD+DVI. This claim is not true, for three reasons: (1) The only BIOS setting I can find that is relevant is what display(s) it uses during boot; once the system is running, that setting should not be relevant; (2) Whatever the BIOS setting was, I had not changed it since the display was working; and (3) When I reset the BIOS to LCD+DVI, it did not display anything on the DVI monitor, either during boot or afterward.

When I phoned about repair status, they said the machine had "passed all diagnostics." No claim that it had actually been connected via a docking station to a DVI monitor.

So back it goes again tomorrow. Unfortunately, they have to send me a new shipping carton; they can't just email me a return label to use with the carton I already have. So I won't have it back until next week.

I do, however, plan to enclose a letter asking them to test the machine with a docking station before sending it back to me. I hope it helps.

Posted: Mon Sep 17, 2007 11:39 am
by ark
The machine came back again today, and finally works. Yay!

There was only one small glitch -- they set the BIOS to display on DVI only during boot, so the built-in LCD panel was blank until it was time to log in. A bit of a tense moment until I realized what had happened.

Posted: Mon Sep 17, 2007 11:47 am
by BradS
Glad they got that all figured out. I'm surprised by the turn around time. Seems like you were able to send your laptop in for repair twice in one week, and get it back just as fast. Impressive.

Posted: Mon Sep 17, 2007 11:51 am
by ark
That's very close to true. I sent it out on Monday; it returned Wednesday. I could have sent it back on Wednesday, but they insisted on sending a new shipping carton. The carton arrived Thursday, and I sent it back on Thursday. They received it Friday morning, had it fixed by Friday evening, and I got it back Monday.

It's hard to argue with that turnaround time. Of course, if they had actually tested it with a monitor the first time, I would have had it back earlier; but having been on the other side of the desk, I know that it is awfully tempting to trust the diagnostics.