Compaq CQ1-1012AN backlight issue

[inflex]

Not quite a laptop, rather it's an all-in-one machine that has an Atom based board.

Machine was working fine, just replacing the fan; I forgot to plug the backlight cables back in to the separate backlight driver board - no problem, plugged them back in and things powered up, for about 3 seconds and then the backlights shut down again.

Any ideas on what I might have blown / damaged? Or was it merely coincidental?

SMD electronics and such are no problem, but I don't know backlight drivers too well.

[inflex]

Re: Compaq CQ1-1012AN backlight issue

I've gone ahead and ordered a replacement PN dual MOSFET as I suspect that's what has gone a bit off-colour, primarily because if you look closely you'll see there's no protection diodes for the MOSFET, hence running the unit without the CCFLs connected probably caused some damage to the MOSFET such to the point that it's not triggering the overcurrent protection.

Couldn't get an exact replacement but ended up with some FAIRCHILD FDD8424H units as a substitute ( on paper it's not as good on the P-ch side but I suspect the chinese unit specs were highly optimistic any how ). That said, the FDD8424H was the *only* thing I could get in the same package and layout at Element14.

Oh yes, I bought a few 36V zeners as well, don't want lightning striking twice!

[inflex]

Re: Compaq CQ1-1012AN backlight issue

UPDATE: Replaced the P-N MOSFET today, no luck, still the same fault; fires up for about 2 seconds and shuts down.

It'd be a whole lot simpler if I could get a datasheet for the controller which is a MP10072ES, and while I can source replacements I cannot seem to find a datasheet for the life of me

MP10072ES NU-PULSE CCFL INVERTER CONTROLLER

[spidey]

Re: Compaq CQ1-1012AN backlight issue

throw it and replace it with 2ea universal inverter. it'll be ok.

[inflex]

Re: Compaq CQ1-1012AN backlight issue

Spidey, did that last night, ordered two generics and a single dual - thanks

[inflex]

Re: Compaq CQ1-1012AN backlight issue

The original replacement unit arrived the other day, fitted, 100% working. Would still love to know what caused the death of the first one, and where the fault was, but now it's just not worth wasting the time.

My generic replacements unfortunately still haven't arrived.