LuDEF P

Hi Zen Mod.

I am back on building the LufDEFP and I am ready to power it up and need some guidance.
All potentiometers are in mid position and power supply is +- 26,3 V DC unloaded.
What to do with the jumper?
Anything else to pay attention to?
PXL_20250530_092913302.MP.jpg
 
start with one channel connected to PSU, in your case - just one channel energized (second channel no mains fuse)

one DVM at output, to observe DC OFfset; for start even few V are OK< goal as close to 0V (up to +/-100mV)
one DVM across rail resistor (0R22, effectively 0R11) to observe Iq; 198mV for 1A8
one DVM across LU (S to D; practically output to Source of cascode mosfet, to observe and set LU Uds to 2V4)

inputs shorted to GND, no load at output
jumper in FE open

power up, all 72 eyes you have on all 3 DVMs to observe is everything in ballpark

fiddle with all 3 appropriate trimpots to set what's needed to set

if you did assembly proper, it'll go as breeze

when you're done with first channel, defuse it, move all DVMs to second channel, fuse it, repeat procedure