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T60p backlight problem - inverter or panel?

Posted: Thu Apr 27, 2017 5:36 am
by bloovis
My beloved T60p Frankenpad (UXGA, T61 motherboard) is having problems with the backlight, and I'm trying to determine if the inverter or the panel itself needs to be replaced.

A couple of weeks ago, the backlight started going out on its own after being on for 10 or so minutes. At first I thought it was a Linux problem, but it happens elsewhere (e.g., BIOS screen). The problem got progressively worse, so now the backlight will come on for a second or so after booting, but goes off immediately. In Linux, I can get the backlight to go on by switching to a text console and then back to the graphics console, but then it goes off a second later. Otherwise the machine is working well; the LCD is visible with a flashlight pointed at it from close range, and an external monitor works fine.

Before I start trying to replace components, I'd like to determine the source of the problem. The inverter for the UXGA T60p is really hard to find on eBay and rather expensive (the only one I could find yesterday was $60). Is there some way to test the inverter to determine if it's at fault?

Re: T60p backlight problem - inverter or panel?

Posted: Thu Apr 27, 2017 5:43 am
by RealBlackStuff
Almost certainly you have a broken CCFL-tube.
It comes on at cold-start, but as soon as it heats up a few degrees, it switches off.

FYI: cheap inverter that will also fit/work: http://www.ebay.com/itm/381877093407
Others:
42T0078 / 42T0079 made by Hitachi, also has marking INVC753
41W1012 / 39T5658 made by Hitachi, also has marking INVC753
13R1014 / 13R1015 made by Sumida

Re: T60p backlight problem - inverter or panel?

Posted: Thu Apr 27, 2017 7:36 pm
by Akimitsui
Since it looks like your CCFL tube is going out, why not replace it with an LED kit?

Re: T60p backlight problem - inverter or panel?

Posted: Thu Apr 27, 2017 10:43 pm
by kfzhu1229
It is certainly a backlight problem. I have a Dell inspiron 2650 with the same problem but I have noticed that you can minimize that problem by using lower backlight levels and hopefully the temperature won't rise to the point where it shuts off in that case. I ended up using medium brightness level for that Inspiron 2650 and its backlight works fine till this day

Re: T60p backlight problem - inverter or panel?

Posted: Sun Apr 30, 2017 5:54 am
by bloovis
Thank you, experts, for the info. The LED kit is certainly attractive, but out of my price range now due to having retired from my SillyCon Valley job. I think I'll look around for another UXGA T60p to buy for parts. There was a cheap one on eBay a few days ago but it sold before I could get my mitts on it :( .

Re: T60p backlight problem - inverter or panel?

Posted: Sun Apr 30, 2017 12:00 pm
by bloovis
Rethinking my (inexpensive) options here, I'm now leaning towards attempting to replace the CCFL. In a previous thread (http://forum.thinkpads.com/viewtopic.php?t=88991), a mention was made of this CCFL for 15" ThinkPad panels: http://www.lcdparts.net/ccflDetail.aspx?ProductID=1699. I'm assuming this will work in the 15" UXGA found in the T60p unless I hear otherwise from you experts.

Thanks in advance!

Re: T60p backlight problem - inverter or panel?

Posted: Sun Apr 30, 2017 1:03 pm
by RealBlackStuff
The same would apply, but you'll find that a BoeHydis LCD is a lot harder to fix.

Re: T60p backlight problem - inverter or panel?

Posted: Wed May 24, 2017 3:13 pm
by bloovis
With many thanks to RBS, I was able to fix the T60p by installing a Sharp 15" UXGA panel, obtained on eBay for $30 plus shipping. Here is his posting describing how to install it: viewtopic.php?p=779362#p779362. It only took a bit of fiddling (removing the Dell inverter and folding the cable, as described in that posting) to get it to fit, and the Frankenpad is back in action.