I have a fixture with 4 MR16 (two pin) halogen bulbs. If I replace 2 of the halogen bulbs with LED's all bulbs work. If I replace 3 halogen bulbs with LED's all the bulbs act like a strobe light (not flickering because it is a constant on/off pattern). If I replace all halogen bulbs with LED's none of the bulbs work.

The fixture does not have a dimmer.

  • 1
    Welcome to StackExchange. Something important hasn't been mentioned. Is there a 12 volt DC power supply? Motion sensor? Lighted switch? Smart switch maybe an older one? 12V DC power supply maybe? Commented Jul 17, 2018 at 15:47
  • Generally MR16’s are 12v....
    – Tyson
    Commented Jul 17, 2018 at 17:01
  • is it possible they are wired in series? if not, replace the driver/transformer/controller or whatever it's called locally
    – dandavis
    Commented Jul 17, 2018 at 21:03

1 Answer 1


The problem is likely a mix of old and new technology: the power supply for the old halogen incandescent lamps is a newer electronic converter, rather than a transformer. Some of these converters have a minimum current for operation, which the LED's don't meet.

You have a few options:

  • Replace the existing power supply with one designed for LED lighting (This is a generic example; choose one that meets your needs).
  • Run with two of each type. You'll save some energy over all-incandescent, but not as much. In addition, the difference in color temperature may be an advantage -- a more complete spectrum, or a disadvantage -- noticeable mismatch in color.
  • Try a different brand of MR16 LED lamp... but there's no guarantee it would work better unless the lamp is specified to work with the particular model supply in your fixture.

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