This picture shows the connector for the DC end of a power supply I extracted from a dead HP MFD (Multi Function Device):


As you can see it consists of 4 pins in a 2x2 configuration. The sockets across the ascending diagonal are hexagonal, whereas the ones on the descending diagonal are square. What is the best way to test the pins without killing the supply and/or my meter?

  • \$\begingroup\$ MFD = Multi Function Device i.e. a scanner/printer? It will help to know a bit more about the device this was removed from, since the connector picture is just about useless. \$\endgroup\$ – HikeOnPast Sep 28 '12 at 3:45
  • 3
    \$\begingroup\$ yes, you're correct, but alas I exhausted my daily supply of stupid because I just discovered that the pinout is printed on the label \$\endgroup\$ – Joe Stavitsky Sep 28 '12 at 3:48

You can safely test it when switched off/unplugged with a multimeter set to ohms/continuity range - probe between all unique combinations of pins and note down which (if any) are connected to each other (reading around 0Ω if set to Ohms or it beeps if set to continuity)

After this test on DC volts range - start at the highest setting and work down (or set it to autorange if it has one)
Test all unique combinations of pins, you should be able to deduce which pin(s) is(are) ground and what voltages are present.
Be sure to note the polarity of voltages when testing.

For example, if you find (only) pins 2 and 4 are connected together, and testing from either of these to pin 1 produces +5V, and testing from either of them to pin 3 produces +12V, then you have a dual output (+5V and +12V) supply with a common ground.

If you need help deciphering the results, update your question with findings from above tests.


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