New power board (r5B6) schematic and layout are also finished. Pre-regulator and post-regulator sections are now merged and phase-control pre-regulator is replaced with the SMPS based on LTC3864 that also allows 100% duty cycle operation.

The power board is directly connected to the Arduino shield using 26-pin 0.1" socket. Thanks to that 3 cables (SPI, power output and sense input) are removed from the picture. Only AC input (X1 connector) from the main transformer and optional Sync cable (X2, X3) now remains.

This revision includes also the following modifications and new features:

1. THT bridge rectifier is replaced with 4 SMD Schottky diodes (D1-D4). They will be additionally cooled via 5mm aluminum thermal bridge inserted between bottom PCB layer and the new enclosure side panel.
2. Down-programmer THT PMOS (Q8) is replaced with SMD version
3. THT or SMD power resistors could be used for down-programmer (R28) and quick current limit (R27)
4. Voltage programming could be local or remote selected using analog switch TS5A9411 (IC15). Remote programming input is protected with ADG465 (IC14).
5. On-board connectors for manual OE and DP switches and LED indicators were removed
6. On-board CC and CV LED indicators drivers and connectors were removed
7. Pass-element (Q4) is mounted below PCB directly on the new enclosure side panel that should be sufficient to dissipate ~15 W (3.5 W for D1-D4 and rest on the Q4 for voltage difference of up to 3.8 V). A hole on the PCB allows access to the Q4's mounting screw.