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Original thread:
Post 6 made on Wednesday April 28, 2004 at 23:03
DeanFred
Lurking Member
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April 2004
1
I finally got around to tracing out the circuit board and creating a schematic for the RF receiver. I have fixed the problem in my receiver. It works great now. I have not gone back to see how much margin there is or whether the RF range has been reduced -- in my 28'x14' theater, the range is sufficient.

I don't recommend this mod for those who can't solder a chip resistor. For those who can:

1. *** UNPLUG *** the receiver from the wall.
2. Pry off the four rubber feet on the bottom.
3. Remove the four philips screws at these locations.
4. Separate the cover and front lens.
5. The board can be lifted off the mounting bosses and flipped over to expose the bottom.
6. Replace R24. It WAS 330K. Change it to a 240K. The resistor is an 0805 sized package -- I used a 5% part. You could alternately solder a second resistor across this one, leaving R24 in place. If you do this, use a 910K resistor and solder it across R24. You can even use a leaded component, if that's more readily available.
7. Reverse the disassembly instructions 1-5 above.

This mod lowers the data slicer threshold at the input of U2 (pins 12/13). The original value had this reference too high so that noise from the RF receiver would sporadically turn on the IR emitters. In doing this mod, the AC (data signal) gain from the receiver is also reduced VERY slightly. For that reason, it may reduce the sensitivity in applications where the remote is being used at the limit of its range. Sorry, there is no help for this situation. For the rest of us who love this remote and have a closer proximity to the receiver, this should do fine. I have only short term testing, so it is also possible that time will age the parts and further change the data threshold. A variable resistor would allow adjusting the value for varying component tolerances, etc. I should wait until longer term testing is done, but I will have lost interest by then and I wouldn't write this up so that others can benefit.

There are no promises or guarantees with this mod. It works for me. I assume no responsibility for your modification according to these instructions. If you don't physically damage your board (just be careful!), you can always return the receiver to its original state with nothing lost.

Cheers!
Dean


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