Upgrading older MB6HC to 48 V

[DuetUser]

Is it possible to resolder a MOSFET and a few small warehouses on the board to be able to apply 48 V or should I forget it ?
We have a fair amount of older MB6HC on large machines and 48 V would greatly help with long fast travels.
I'm aware we can order new Duets or expansion boards.

[dc42]

@DuetUser the issues that I can think of that would make this difficult are:

• The six large capacitors on the board are likely to be rated at 50V. When operating at 48V you should allow some margin, because when you disable motors they pump energy back to the supply, causing the voltage to rise. We use 63V capacitors in the newer 6HC and 3HC boards.
• The main power input feeds not only the drivers and those six capacitors but also the 12V and 5V regulators. Those regulators are rated at 40V max input voltage. So you would need to cut traces or desolder components to allow you to feed 24V from a separate PSU to those regulators.
• The voltage divider that is used to measure the VIN voltage is not designed to handle VIN voltages as high as 48V. You would need to change one of the resistors in that divider to get the reading in range.
• The heater and fan mosfets are only rated to 40V. You could set both fan voltage jumpers to 12V.

[DuetUser]

@dc42 Thanks a lot David, I should definitely forget it