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Affected boards

This issue affects Rev 2 boards with order number #1214 or lower. If your order number is higher than #1214, this fix has already been applied to your board.

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Problem

When you connect a 30V or higher power supply to the board without a motor connected, a brief voltage spike (approximately 1 microsecond) destroys the DC-DC converter.
This issue does not occur if you:
  • Use a standard 24V power supply
  • Have a motor connected to the board before powering on

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Solution

Add a to clamp the input spike to a voltage the DC-DC converter can tolerate.

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Required part

Part NumberDescriptionApproximate Cost
1.5KE51CATVS Diode~$1 USD

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Installation steps

1

Prepare the diode

Bend the leads of the 1.5KE51CA diode to match the solder pad spacing on your board.
2

Trim the nearby pin

Trim the pin marked in the image below to ensure it doesn’t contact the diode lead after installation.
Skipping this step may cause a short circuit between the pin and diode lead.
3

Solder the diode

Solder the diode directly to the board as shown in the reference image below.
Verify that the diode leads have good solder joints and no leads are touching unintended pads or components.