On Dec 16, 3:46*pm, Jeff Liebermann wrote:
On Fri, 16 Dec 2011 09:54:55 -0800 (PST), Robert Macy
wrote:
FINALLY!! *I verified that the LCD screen is validly changing pixels,
all I need is the backlight.
Ok. *The panel is good. *That leaves the LCD inverter and/or the CCFL
backlighting tubes.
Measure voltage. *If the tube is OFF, is that the firing voltage?
trying to get the tube to arc? sounds about right. *400 to 600 Vac
firing voltage then goes down to the 20V 1A range.
Could you please re-write that in English? *It's not clear if you
measured anything, what you measured, how you measured it, and what
numbers were seen.
Would you verify that there is NO polarity to the fluorescent tubes
supply?
The CCFL lamp wires are not polarized.
However, the connector from the CCFL tubes is sometimes polarized. *It
is possible to plug in backwards. *It will sorta fit, but not be
seated correctly, resulting in no connection. *My guess(tm) is is what
you've done. *Unplug the cable from the CCFL lamps and LOOK AT THEM
carefully. *Match it with the socket on the inverter. *Hopefully, that
will fix it.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
#http://802.11junk.com* * * * * * *
#http://www.LearnByDestroying.com* * * * * * * AE6KS
Is there any possibility that the Lamp would work, the inverter would
work, but some 'controller' is toast?
Looking at the corrosion pattern on the inverter PCB, it looked like
the high voltage could have gained access back to the multi-pin
connector, which [to me] translates to "any IC driver wired to that
connector is likely to have been fired." Yet those same drivers are
probably on the system board. which may, or may not, affect the system
operation.
Measure voltage. *If the tube is OFF, is that the firing voltage?
trying to get the tube to arc? sounds about right. *400 to 600 Vac
firing voltage then goes down to the 20V 1A range.
Could you please re-write that in English? *It's not clear if you
measured anything, what you measured, how you measured it, and what
numbers were seen.
Oops, English is my native language, just doesn't often show.
Years ago, one of my clients made OCR electronics, my first design for
them was to design reliable fluorescent tube power source *and* make
certain the light pattern across a sheet of paper was uniform. To
'fire' the tube took any where from 400 to 600 Vac and once fired [the
tube is now filled with conducting plasma] the operating voltage drops
to 20-30 Vac at 1/2A, or so.
My [confusing] words were more of memories, than statements. I did
not, have not, no real way to do so yet, measure any voltages around
the Laptop.
Is the 'seating' of the connectors really that critical on the
Laptop? I mean those connectors are cheap, low insertion force,
miniaturized molex thingies that I find hard to believe provide
reliable connection at all. But, are they really likely to be the
problem, more than the likelihood of a non-operating component?
Regards,
Robert