That explains the superfluous cable grommet around the PWM cable. This is just a standard part with an output cable added and some heat shrink around it. Great reuse of a well known design.
That was my thought as well.
I haven’t looked at specs on that chip (yet), but I think I would try to heat sink it for any load significantly higher than 1A. Another upgrade that may be worth trying is to add a battery input, so that you can run the DC motors off a separate battery from the rest of the Vex system.
I did test a bunch of random devices, and it always behaved as I expected it to.
Two VEXplorer motors (in parallel): Worked just fine. It sounded like the RPMs fell off just a tad when I attached the 2nd motor, but hard to tell. Seems like this would work well to drive a 4-wheel drive chassis using 4 VEXplorer motors, plus 2 of these adapters, plus two Y-cables.
VEXplorer LED Modules: Worked just fine. Since they are LEDs, they only work with one polarity. Attaching two modules such that one is reverse-polarity allowed me to alternately activate one or the other module. As previously stated, the LEDs flickered at the intermediate brightness levels, but this is to be expected from a switching motor controller.
Incandescent Light Bulb: Worked just fine. Full bright at 0, dimming down to dark at 127, returning to full-bright by 255.
12VDC relay: Worked just fine. Relay closed at just over 200. This board can alternately drive two relays if you put a rectifier in series with each relay coil. That would allow the two buttons on channel 5 (or 6) to each control a separate relay using a single PWM->DC adapter.
Random low-voltage DC motors: Worked just fine. Some higher-torque gear motors I picked up from Jameco ran like a dream. Also ran a DC fan - it was kind of neat to control the fan (both speed and direction) from the Vex.
From looking at the output signal on the O’scope, the drive is a 2KHz duty-cycle output. It was fairly stable, and had nearly no dead-band. Basically 0-30 were full negative, 128-130 were dead off, and 222-255 were full positive. If you are running something like the camera that would not take kindly to being pulsed every 500usec, you should stick to 0/127/255 values.