[ltp] Re: My T22 backlight has died - how do I fix it?

[Wookey]

+++ Bert Haskins [05-08-25 10:49 -0400]:
> 
> Every Thinkpad ( 600x 770xy 390s, A2xx series, A3xx ) that I've ever 
> worked on  has used a CCFL tube.

OK, and a peruse of the web suggests that this is indeed the case for the T22.

> I do check the inverter first though.
> I use an inverter that I keep for just this purpose and if the screen 
> does light up I debug the other circuits.
> My test inverter runs on it's own power ( battery ) so it's not affected 
> by other problems.

> The CCFL tubes are VERY easy to break, imagine a #2 pencil lead that is 
> 12 or so inches long
> and you will have to solder the leads on to this and manage to wiggle it 
> back into the lcd assembly.
> 
> Even after doing this a few times, I still manage to break about one out 
> of six and I always have at
> least three before I start.
> Replacement tubes are about ten dollars each.

Right. I built a CCFL caving light a few years ago although the tubes were
relatively short at about 12cm (4"). I can see that longer ones would be
very delicate. Those tubes ran at about 250V - are the longer ones
correspondingly higher voltage? I ask because I don't have spare inverter
board so I'm going to have to use a meter/scope to guess if the inverter is
working or not. Anyone know the voltage and frequency I should expect?

If you still break them after fixing several then it must be tricky!

> Typically the 'buy a new old one' could have its own set of problems.

Indeed. The only reason to consider this option is that the case is broken,
because the chassis is broken (near the back right hinge). And my battery is
very tired and the replacement is dead. So I'm just wondering if I can be
bothered fixing all these things or if it's time for a newer, faster, better
laptop, especially as work will be paying :-)

I'll give it a prod just to learn how to do it, then decide. As both
inverters and tubes are cheap I might as well.

Wookey
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