Hi
I have the MX1C and I fixed it to work at full sync speed with my flashes.
You open up the transmitter and move (solder) the blue wire (marked Wake or W) to the top right pin on the hot shoe.
thank you again "Bojidar Dimitrov's Pentax K-Mount Page"
Dead easy, and the you have wake function.
The problem is that the reciever needs pre notice when a flash triggering is about to occur. Same as the rf-602
You will need to half press the shutter button or else it will not sync up above 1/80.
You can see it working on the triggers, the green light on the TX blinks then the green on the RX blinks.
I measured the half press activity on the hotshoe of my K200D and found the Digital Com pin to be the one.