Suggested mod:
Do it : before further use.
Why : UP LED current is uncontrolled and could lead to failure of the up LED array (individual LEDS) . There is no current limit resistor...Thermal runaway occurs.
Fix : insert 2.2 ohm , 1/4 W resistor in series with the UP LED power wiring.
Mod : reduces maximum LED current, instead of the Rds ON of the MOSFET switch being the limiting factor...
Current before : ~ 500-600mA
Expected current post mod- ~ 300mA. It's not critical. As long as it is a bit less.
Determined: Using Thermal camera, voltmeter, lightmeter, with assembly removed from machine.
Result : LEDs run cooler, less likely to blow up. reduced variation between LEDs. Plenty of light range for the camera.
How to:
There are a pair of wires that run from the microcontroller PCB on the LHS of the machine to the UP led block. There is a 3 pin connector onto the microcontroller PCB. (two wires used).
You can access this cable by removing the UP light assembly (2 x HEX key bolts) (after 4 cross head screws for the cover) , and dragging up the wiring a little. Or you can access on the LHS compartment, it is labelled UP-LIGHT. Top of the Microcontroller PCB .
Things are well labelled in there, actually. Good on QiHe for that.
Down LED light to TBD.. Most likely same, needs some series R...
Easy mod, and QiHe to fix.
Glen.