Toshiba P850 backlit keyboard upgrade?

Recently purchased a second hand P850-31L from a friend. Said friend had previously attempted to upgrade to a backlit keyboard and it hadn't worked, so assuming this board was a dud (and as the frame of the keyboard had been damaged anyway), I bought a new backlit board from eBay.

My system didn't come with a backlit board originally, but does have the connector on the motherboard for one. After hooking up the connectors, no joy, no sign of life on the backlighting. Fn-Z doesn't work, and there's no settings for the board in the BIOS as there 'should' be. Whether backlit models have a different BIOS, or the setting only comes up when a compatible board is connected, I'm not sure.

Is it possible to add backlighting to this model? I assumed that if the connector was there, so was the functionality, but evidently not.

 

Does not look like possible. And Toshiba BIOS is pretty well locked down, and you know the rest.

 

You might need a matching ec, which flashed along with the bios (e.g., extract this file; Toshiba Satellite P850-B BIOS 6.70). Other than that; verify that there are smd components right after the bl socket. However, if they'd save cost on a non-bl model, then they'd have left the connector unpopulated as well ($0.10 saved = $0.10 earned).

If it's all there, then a near-matching ec is likely to work. This risks bricking the board, however, so without a programmer this is a rather exciting procedure.

Now, the on-off switch might use a small, 3-pin relay close to the bl connector. Bypassing that relay will turn on the backlight, this is something you can easily check while it's running. If it turns on, you might solder a wire to make the connection permanent, optionally with a switch in-between, if you want to be able to turn it off again. The other design option is that one of the bl pins (six in total?) is the on/off switch, triggering a relay on the kb itself. Measure all pins with a multimeter, see if anything is 'live'. Either shorting the on/off to ground or supplying a tiny current to it would turn on the backlight. Make a good photo of the connector, that makes things easier to designate.

 

Have been trying to look for a model with the same board and features as mine that had backlit (so one with a GT640M 2GB) - I found one but the model number escapes me. The BIOS for the two models when downloaded looked identical.

The backlight connector has 4 pins. I will get a picture and check for nearby components next time I take the machine apart.