JP1 Remotes

Hi all,

Using a self-made Parallel JP1 cable that I have been using for years.

I have two 8811's and one 8910. Had them for 5+ years.

Now one of 8811's is not talking to PC via this cable (Can not d/load or upload, and interface check fails too).
Same JP1 cable works perfectly fine with other 8811 and with 8910.
Same set of batteries is used in all cases, to rule out battery factor (I am using fresh 1.5V primary non-recargeable Duracells)

The "sick" 8811 quite happily responds to all button presses, blinks the red LED and controls the appliances via infrared - so, it looks like it's feeling OK, but can't talk via JP1 to the PC.

Tried the factory reset (Set => 9-8-1) - didn't help.

Opened the 8811 unit and inspected the tracks and soldering around JP1 connector - all looks OK.

Any ideas as to what this may be, and how to get it back to talking to PC via JP1?

Thanks a lot.

digital_silence wrote:Hi all,

Using a self-made Parallel JP1 cable that I have been using for years.

Same JP1 cable works perfectly fine with other 8811 and with 8910.
Same set of batteries is used in all cases, to rule out battery factor (I am using fresh 1.5V primary non-recargeable Duracells)

Parallel cables can be very finicky. While all the other cables require good batteries, the parallel cables might need to have weak batteries or no batteries at all. Each of my JP1 remotes needs a different battery trick to talk to my JP1 parallel cable.

Thanks, I'll try to connect a variable power supply to remote instead of the batteries and play around with voltage range.

Is there a schematics for URC8811, or at least a pin layout of the 6-way JP1 connector with the expected signal waveforms?

Got to the bottom of it.

The problem was in the 6-way pin header JP1 connector on the 8811's PCB.

Due to a poor quality of the PCB, the solder pads develop dry joints after a while as the connector gets pushed slightly every time you plug the JP1 cable into it.

Nasty thing, as it is pretty hard to spot - soldering looks perfectly fine from outside, but solder blobs don't make proper contacts with the copper pads under them (but I've been there too long to miss these things... :)

Removing the connector, cleaning the pads and soldering the connector back fixed the problem completely.

Just make a note of this - I have a feeling that I will be not the only one with that issue.

Regards,
:-DS