I just obtained a PCL-300, along with the software, manual and everything I need. The software appeared to install well and the PCL-300 is recognized by the Windows XP computer. My question is this: The 8-pin plug on the PCL-300 is supposed to have one of the 8 pin sockets plugged (blocked) so that you are prevented from connecting it in the wrong orientation. On the unit I got, this plug is missing so I can't tell which way to plug it into my MX-650 remote. I don't want to try it without knowing and take the chance of damaging either unit. So I'm asking a favor: For anyone who still has a PCL-300, could you look at the plug. It is rectangular, and will have an arrow molded onto one of the two edges. Can you tell me if the socket that is blocked is near the arrow edge of the plug, or the opposite edge?

If I were you. I wouldn't use it, it fried two mx-350 of mine.

The advice was probably good advice, nevertheless I didn’t want to just give up. I decided that I wanted to try out the PCL-300 anyway, but I needed to proceed carefully since I didn’t know which way the connector plugs into the MX-650. I figured a few resistance and voltage checks could confirm which way the plug should go in. Since I couldn’t open up the PCL-300 to ring out the wiring to the plug, I powered up the PCL-300 from the computer USB and checked voltages on the plug. With the arrow on the edge of the plug facing upwards, I measured GND on the top left side (near the arrow). The rest of the sockets on the left measured nothing. Starting at the top of the four sockets on the right, the first one measured nothing, then +5V for the next two, and 3.3V for the bottom right (which turned out to be Vcc).

I just happened to have the back of the MX-650 removed for other reasons, so this also helped confirm a lot by looking at the circuit board. I found the 7-pin connector (CON2). While holding the remote upright, and looking at the connector, it has labels on the circuit board as follows:

The right hand three pins are GND, with the 4th (lowest) pin being absent (reserved for connector key alignment).
Starting at the top of the four pins on the left, and going down, there are labels that say GND, P1.6, P2.0 and VCC. P1.6 and P2.0 go to resistor/diode static protection circuits (R16 and R15 and D7 and D6). I am assuming they go to the microcontroller.

With the MX-650 powered from an external power source of about 5 volts, P1.6 measures 3.3V, P2.0 measures 1.75V, and Vcc measures 3.3V (apparently regulated down from the raw voltage of the batteries).

I did a few experiments with loading the voltages on both the PCL-300 and MX-650 with moderate values of resistance, to see how “stiff” they were. This helps to determine which pin is input and which is output. The results were:

PCL-300: P1.6 soft (input), P2.0 stiff (output)
MX-650: P1.6 stiff (output), P2.0 soft (input)

So they both match each other, and at that point I knew that I wouldn’t damage the MX-650 from wrong voltages, at least. It’s a good thing I checked. +Power and GND are on diagonal opposite ends of the connector. If I had reversed the connector, this would also reverse power. I most likely would have damaged one or both of my devices. In the end, the arrow on the edge of the PCL-300 connector should face towards the top of the remote when it is plugged in.

IC chips inside the MX-650 include the Samsung S3P8454XZZ microcontroller and the SST 39VF080 multi-purpose flash memory chip. Operating power specification is 2.7-3.6V for the 39VF080, so that matches the 3.3 volts measured on the PCL-300 I/O connector for Vcc, as well as the 3.3 volts measured on the MX-650 Vcc. P1.6 (Port 1 Pin 6) of the I/O connector refers to the SO (synchronous output?) of the S3P8454XZZ, and P2.0 (Port 2 Pin 0) refers to a general I/O port or interrupt. Both P1.6 and P2.0 are described as being capable of being either inputs or push-pull outputs, according to firmware programming.

So there you have it. In the category of “better late than never,” this information might have been more useful about 10 years ago, but I thought I’d share it anyway.

So I plugged the two devices together while the PCL-300 was still unpowered. After plugging the PCL-300 into the computer, the remote seemed to have no objections. After taking the initial step of opening the UPLOAD menu, the software correctly identified the MX-650. I uploaded the MX-650 configuration to the XP computer and then downloaded just the user configuration (only) back to the MX-650. The process worked well and the MX-650 is still working fine.

When I first installed the PCL-300 software on the XP machine, I asked it to do a live update. From everything I had heard, I fully expected it not to work because the internet link that it draws from should be long gone. To my surprise, it actually worked, and I could see a progress bar while downloading various program updates. The main program folder now has quite a few updated files, but the UPDATES folder is still empty, so I thought that no IR database files were included in the live update. I decided to try updating the firmware and IR database on the remote anyway, using my previous backup that I uploaded from the remote (thinking it wouldn’t change anything). When I did so, the firmware updated from V1.01 to V1.02 and the IR database updated from V1.66 to V1.83. Apparently, the .PCL file that you back up from the remote only stores the user configuration, not the existing firmware or the IR database. Those two are stored in the various files that are in the program folder, that don’t have .PCL extensions. The date stamps of those files are dated with the date that I downloaded them, so they don’t give any indication of when URC last updated them. Searching this forum for version 1.83 indicates that it was probably 2008. The available IR codes match the ones listed in the latest MX-650 manual that I can find, which is Rev. 07 dated 4/2/2009.

Some of the updated 3 digit IR P-PRO codes replace older ones that can no longer be used. Yamaha Audio receivers are an example of this. So I had to refer to the Rev. 07 manual and stop using the older ones.

The HELP menu lists two options for recovering MX-350 remotes. The two options are split up by older or newer serial numbers, so you choose which series your remote belongs to and download to the remote in recovery mode. There is no recovery listed for the MX-650. It sounds like the MX-350s may have had some problems that the MX-650s didn’t.