When batteries splooge, electronics are the first to suffer

The business end of the PCB inside the TV remote, featuring its infrared LED and make and model information.

You go a week or so without looking at your TV, only to pick up the remote control and find it stone dead. Then, when you pry off the battery cover to swap in some new AAs, bits of the old batteries fall out, along with a shower of greenish-whitish powder. After you pick up the disc that used to be the battery’s cathode and wipe the powdered battery chemistry byproducts up off the floor, you dump the battery bits that stayed stuck in the remote into a garbage bin.

Before replacing the battery cover, you peer through holes in the battery compartment, itself thoroughly encrusted with white powder and note that the batteries seem to have done an exemplary job of splooging their guts all over the remote’s PCB. Rubbing off the stainless steel battery terminals and finally slotting in two fresh AAs doesn’t return the remote to duty, so you Ziploc bag the inert object and set it aside. A few days pass.

An almost-complete view of the button-contacts side of the remote control PCB.

The remote snaps together, so you have to gingercarefully separate the upper and lower halves of its shell with a razor-thin metal tool (or a butter knife). Next, you remove the PCB and set it aside. Like the PCB itself, the backside of the silicone membrane keypad, the rigid plastic insert that goes between the back of the silicone and the button-contact side of the PCB, and much of the shell are slathered in white powder. Those get toothbrush-and-foaming-soap treatment and are left next to the sink, standing on end on some paper towels to dry.

It doesn't look pretty, but it seems to still work.

Gently, using lint-free pads and EtOH, you clean both sides of the PCB. After hooking it up to a benchtop power supply and providing it with 3V of DC, you train the lens of a digital camera on the remote control’s infrared LED. With one eye on the camera’s screen, you press the head of a metal bolt against a randomly-chosen E-facing-E conductive rubber pattern, one of many designed to be spanned by the conductive-rubber inner surfaces of the keypad buttons. The ensuing series of purple flashes visible on the camera LCD tells you that the remote may be fundamentally alright.

But there’s only one way to know for sure, so you disconnect the power and clip on retractable hook leads attached to a 3V battery pack, and leg it to the TV. With the bolt head, you trigger the conductive rubber tentacles corresponding to the power button. The TV switches on. You channel surf for a moment and then turn the TV off once more. When the plastic shell halves and insert and the silicone membrane are dry, the remote can be reassembled.