Dell Mini 10v backlight PWM mod progress

As part of my ongoing attempt to increase the screen backlight PWM frequency on my Dell Mini 10V, I attempted to remove the 40 pin connector.

First I preheated the board in a fan oven at 140C for 5 minutes. Lower than ideal but I don't know how accurate the oven temperature is. I forgot to remove the lithium button cell but it seems to have survived (open circuit voltage still the expected 3.3V) so my cautious heating probably saved it.

Preheating the board in an oven

I then attempted to melt the solder with 350C hot air. All I accomplished was slightly damaging the plastic.

Connector damaged by overheating

I added some aluminum foil for heat shielding and tried again, preheating then using 400C air.

Aluminum foil for heat shielding

It still didn't melt, and I was worried about further damage so I did not continue. I reconnected the display and battery and powered it up to confirm it was still working (it was).

The pin I need to cut is embedded in the connector so it's not really possible to get to it with side cutters. Seeing as desoldering failed my only option was to drill through it in-situ. I used a 0.5mm carbide bit at 30000rpm. This was difficult because of the angles involved but I successfully severed the connection and confirmed that shorting the top part to the bottom part restores functionality.

Pin broken by drilling

I soldered some wire-wrapping wire to each part of the pin to tap into the signal.

Wires soldered to both parts of broken pin

There's some empty space next to the wireless card, so I routed the wires there. I can use this space to hold a microcontroller to modify the signal and hopefully increase the PWM frequency to at least 2kHz.

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