Electronics Workbench, PC Tweakage

Dell Optiplex GX270 Power Control PCB Connections

The general idea is to gut an old Dell Optiplex GX270 and stuff the high-voltage parts of the sewing machine controller inside a well constructed and solidly grounded metal shield inside a not-too-ugly plastic box. It’d be nice to reuse the power control button and status LEDs on the front panel…

The few parts on the front of the through-hole board:

Dell Power Button PCB - component
Dell Power Button PCB – component

The copper side, with annotations:

Dell Power Button PCB - copper
Dell Power Button PCB – copper

The red tracer on the ribbon cable goes to Pin 1, which is a blind key on the PCB.

The LEDs do not have ballast resistors, so those must go on a circuit board somewhere else.

The connections:

16 14 12 10 8 6 4 2
Gnd nc nc nc nc HD+ HD- Button+
Gnd nc Gnd Pwr Y+ Gnd Pwr G+ Gnd Key
15 13 11 9 7 5 3 1

 

3 thoughts on “Dell Optiplex GX270 Power Control PCB Connections”

  1. The LEDs do not have ballast resistors

    Sigh. Integrated resistor LEDs never fully caught on, though we sold a bunch of them over the years. They solved a lot of problems, but the marginal price increase hurt. (That, and they weren’t very compatible with dual-color lamps.)

    1. A fixed resistor restricts the input voltage range, so you must stock half a dozen different “identical” LEDs. Only one or two of those would sell enough to make their premium price worthwhile, while the rest lingered on the shelf until they turned into weird surplus items on my shelf.

      I’m sure they’re still made for extreme high-volume users. Those are the same users who care desperately about the cost difference between a fancy LED and an 0201 resistor, so maybe not.

  2. Pingback: ATX Power Supply: Pushbutton Control | The Smell of Molten Projects in the Morning

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