# Panasonic TOughbook CF-71



## mytime34 (Feb 6, 2005)

Hello all,

I have a CF-71
p3-600

Here is my issue hope you guys can help

I had the machine running winxp and on battery (draining battery to reset the memory) and everything was fine. It drained all the way down and shut off. I than hooked the power supply back up to it and it showed an amber light for a few min, than it started blinking red and now nothing works.

With the battery installed it does not charge,
with the ac adapter plugged in I get no lights,
when I try to turn on power I get nothing
I even tried a differ batt and power supply.

Is there a fuse on the board that I can check?

any help would be great


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## banditbob (Jul 10, 2008)

I have a similar problem. my cf71 battery light flashes red most of the time, even when it's shutdown and unplugged. i've tried changing the battery for a known good one and it does the same. also opened the battery and checked individual cell voltages and they're good.
When running on battery it says it's on ac power until about 50% then either shuts down or (if i disable emergency shutdown) decides it's on batteries, shows orange light and runs fine.
Also it only charges to 70-80%. i've tried flattening the battery to reset the power meter but makes no difference. can anyone help me please cos it's driving me nuts.
I tried throwing it out the window but it still works.............


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## banditbob (Jul 10, 2008)

I'm still trying with this one. have checked the battery in a good machine and itcharges and discharges fine. the problem seems to be in the power switching circuit (mosfets) in the laptop. if anyone has similar problems or can suggest whats gone duff please let me know. i'll do the same as i go along.


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## banditbob (Jul 10, 2008)

Ok. for all you tech heads out there here's the fix.
i stripped the laptop and took it's motherboard out, i powered it up with both battery and adapter and started checking voltages with the multimeter. as my finger brushed accross Q40 i burned it. ha ha. Q40 was short circuit and getting hot. once i removed it the problem went away. charging/running on bat and ac/no red flashy light. Q40 seems to be in parallell with Q44 so that is maybe now doing all the work and may blow soon so i'll be replacing Q40 as soon as i can source a A1712 mosfet. seems to be obsolete. typycal huh.


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## jcm027 (Aug 18, 2009)

I just got this cf71 will you tell me how you got the bottom of the case off without breaking sides,,,
thanks


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## banditbob (Jul 10, 2008)

You shouldnt have to break anything, it all comes apart real easy once you find the hidden screws. if you unclip the strip accross the top of the F keys first, then prise up the keyboard *carefully*, its got tabs at either end.
you can then get at all the screws, including the ones under the battery and hard drive caddy.
good luck.


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## jcm027 (Aug 18, 2009)

thnks, got it,,,the plug for the power cord was messed up,, I took it out and hard wired the cord,,didn't know if this thing worked or not,,,it fired right up


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