PSM External Power

Important new guidelines for using the External Power Jack !!!

Although the manual says you can use 4 to 9 VDC, operating the power switch with more than 6 VDC applied may damage the PSM !!!!

We now recommend using only 4 to 6 VDC Regulated power supplies with the PSM.

You can use up to 9 VDC provided you do not move the USB/EXT switch while power is applied.

Reasons for change:

Testing has revealed two things can can damage the FDTI USB chip on the PSM.

	1: Regular 9 V power supplies can actually put out 13 VDC. This is why we no recommend only regulated power supplies. If you're not sure, please measure the voltage to make sure it is 6 VDC or less.
	2: The power switch has 3 leads; USB power input, External power input and output. When switching between USB and EXT (or vice versa) all 3 leads are momentarily connected together.

These two factors can lead to large voltages (well above the rated 6 VDC MAX) being applied to the FTDI chip. Even though this is just a transient voltage, it has been shown to be enough to damage the FTDI chip.

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