[HH] dead IR remotes

[Bill Bogstad]

On Mon, Aug 20, 2012 at 3:12 AM, Tom Metro <tmetro+hhacking at gmail.com> wrote:

>
> If you're curious, you can see a picture of the type of remotes in
> question and the device they control here:
> http://mvpmc.wikispaces.com/Mediamvp

You are still using a MediaMVP?   Is that paired with PVR-150s as well?

>
> My IR testing has been to observe the IR activity light on the device
> being controlled. I have no reason to question this, though I ought to
> take a look at the output of these remotes through a video camera to see
> if they are perhaps producing a signal that the receiver is completely
> rejecting.

A regular digital camera will work for this as well.   I'm actually
using the same kind of remote
as well (tand have noticed some corrosion of the battery
>
> Like most modern IR remotes, it's a really simple design: a 33 uF
> electrolytic cap filtering power, a 24-pin fine pitch DIP surface mount
> micro (no part numbers I recognize), crystal, few resistors, a few
> transistors (appear to be used to multiplex the keyboard), an IR LED,
> and a driver transistor.
>
> It's a single sided board with the only through-hole components being
> the cap, crystal, LED, and the battery contacts. The cap and crystal are
> close enough to the battery compartment that they could have been
> exposed to some moisture and compressed air, but I can't see that
> killing them. I know cap isn't shorted, and if it failed open, the
> remote would still work, but would have reduced range due to starving
> for current...or it might have a truncated pulse train if the current
> spike causes a "brown out" for the micro. Viewing the output on a video
> camera might shed some light on that.
>
> Short of probing things with a scope (checking that the oscillator is
> running, etc.), I'm not sure what else to do.
>
> (On a side note, I noticed the silicone keyboard has a sticky residue
> all over the surface that contacts the PCB (and on the PCB), which I've
> found when disassembling pretty much any IR remote that's more than 3 or
> 4 years old. No, soda or other liquids haven't been spilled into it. It
> seems like the silicone naturally degrades in this manner. And yet it's
> always on the surface touching the PCB, as if something in the PCB
> coating causes it. I've tried researching this phenomenon online in the
> past and found nothing useful...other than products for repairing the
> carbon pads on silicon membranes. I'd sure like to understand why/how.)
>
>  -Tom
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