fix for rr501 lockups?

Question

I have an IBM branded rr501 which regularly locks up. After a lot of googling I found that it might be related to dim commands. Sure enough, I can very reliably lock it up with an RF remote by holding down the dim button.

Has anyone written a summary of what is known about this lockup?

I found some discussion of a similar lockup in the TM751, and possible solutions involving changing the gain of an amplifier stage. "I now suggest replacing the 1k resistor found between pins 3 and 6 of the LM358 op-amp on the TM751 RF daughter board with a 3.9k resistor." Is this the definitive fix for the TM751?

Anyone know if a similar fix works for the rr501? I did try reorienting the antenna, with no effect.

bcboy · Accepted Answer

Thanks. An amusing bit I discovered: my standard X10 wireless remote (4001X, or similar) invokes this bug, but my wireless wall switch (4095W, or similar) does not. Neither does my HTPRO universal remote. The problem seems to be unique to the palmpad style remotes.

I have no idea how the RF signal from the palmpad is different, but it clearly is different.

Dave Houston · Answer

I don't think there's any reliable fix other than replacing the PIC with onethat uses different firmware. Better yet...

Dave Houston · Answer

That's a bit odd. I did quite a bit of experimentation a few years back withboth the TM751 and RR501 and do not recall anything that would explain that.I used a Firecracker to send the signals.With either the TM751 or RR501 I could induce it and stop it at will byreorienting the antennas. It was clear that the antenna was picking up thesignal on the powerlines and that the feedback loop lasted long after theinitial RF signal from the remote had stopped. Some units were moresusceptible than others but the real difference appeared to beenvironmental. I never saw it unless I was trying to induce it but otherssaw it always. One of the people who saw it always sent me their TM751 andit behaved differently here.     wrote:

Sylvan Butler · Answer

Palmpad dim repeats very quickly compared to most RF remotes.  Don'tknow about the specific ones you mentioned.sdb

fix for rr501 lockups?

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