How to keep a RCU810 from sporadically resetting

[Egmontster]

Hay guys,
I am new at this JP1 stuff and brand new here. I have a RCU810 remote that had the reset problems. While I was in adding the JP1 connector, thanks to your excellent instructions on this, I added a 220uf 63V Electrolytic capacitor (just fit) to the battery terminals of the set. It is probably bigger than necessary to get the job done but it worked for me. It fits very nicely into the hollow of part of the casing for the remote. The cap can supply the inrush current needed by the backlight to start. That was my theory. The inrush current was taking the power supply to below the point where the CPU can operate. So you get a reset.

Anyways, I may be way off but I have not had one instance of the reset since I added this cap. I don’t think it is a coincidence but it is possible. Anyone else care to give this a try and see if it works?
Cheers,
Michael

[The Robman]

Thanks for posting that info Michael. I'll be interested to hear if anyone else tries it and of course, let us know your results. Any comments from any aspiring EEs in the house?

[johnsfine]

We've had a significant discussion of this issue before.

Long ago I was quite sure that the power drop as the backlight turns on was the cause of the reset, so a solution such as the one described above (or just getting batteries in better condition) would fix it.

But someone (sorry I always forget names) did better testing and determined that the RESET input to the CPU is very sensitive to noise.

The best solution seems to be making a tiny connector to go over the jp1 pins when you're not using the JP1 cable, which connects the RESET signal to plus voltage.

There have been enough reports linking the reset problem to the backlight comming on that it must be a factor. But it is probably just a noise source (and better batteries or that cap just reduce the noise).

There is significant variation among units. The factor that varies seems to be how noise sensitive the RESET signal is. Some units can handle the noise of the backlight turning on. Some can't handle that but are fixed by fixing just that. Others are sensitive to even smaller noise and need the RESET signal solidly pulled high.

[Egmontster]

Ok, thanks for the information. If i have more problems i will give that a try. Pin 5 is reset and pin 1 is VCC yes? I think that is right.

I really am enjoying this JP1 stuff. Thanks to everyone for providing me yet one more way to spend time messing with cool hobbies instead of mowing the yard (or something like that).

Cheers,
Michael

Sorry, never mind, I found it in this thread. I should read a bit more I guess. Thanks again.

[The Robman]

Michael, did you really use a 63v cap or was that really a typo for 6.3v? According to Tommy Tyler, UEI generally uses 10v electrolytics for the capacitors they put in nearly all remotes, and this is the voltage rating that he recommends.

[Egmontster]

Hi Rob,
Yes it was a 63 volt cap. It was the only one i had on hand at the time that would fit nicely into the remote with the highest uf rating. I am not absolutely sure on this but, I don’t think that the voltage rating has any real effect on the function of the device. It is only, as far as I know, a maximum working voltage really.

The higher the rating the physically larger the cap. A 220uf cap with a 63 volt rating holds the exact same energy as a 220uf cap with a 10 volt rating at the same voltage. It is just that the 10 volt cap would pop (not a nice sound) at higher voltages. Again, I may be off on this. If someone else more knowledgeable could correct me if I am wrong I would appreciate it.
Cheers,
Michael

[DavidEC2955]

Due to eye surgery I am unable to do close soldering any more so I use a 'POGO PIN' to program my RCA810B's...

I had two of the "A" which did not have the clock reset troubles but the "B" seem to reset the clock every time I hit the "TV" button?!?

Right now I have "RIGGED" a "PAPER CLIP" jumper for pins 1+5 that is held in place by the battery cover...

Can anybody make a better non-solder fix?

--David

[underquark]

I have "RIGGED" a "PAPER CLIP" jumper for pins 1+5 that is held in place by the battery cover...Can anybody make a better non-solder fix?

If someone who owns one of these remotes steps in and helps then that would be great but otherwise, do you have an image of your interface that might help others come up with ideas? I'm thinking maybe short pogo or a modification of my spring connector. Nils Ekberg's suggestion (same thread) for gluing on a piece of perf board sounds a good idea to stop your connection slipping.