Any hard-core electrical engineers specialized in LED drivers reading this blog? If so, I would appreciate your input!!!!

Until today, we were proudly a 100% LED-illuminated household. Unfortunately, I faced an enemy I could not slay: Two G4/12VAC lamps in my IKEA range hood.

I purchased two Calex brand 1.5W 12VAC G4 LED lamps and swapped them a couple months ago for older G4 LED lamps, one of which failed (the previous ones lasted 3 years, and considering the rough thermal load for these, I think that’s acceptable).

But after a short warm up period, the new LED lamps started pulsing. Strangely, they pulsed in unison. A random, non-repeating pattern. Which immediately led me to think it is a transformer problem, not a lamp problem.

So today I wasted my morning disassembling the range hood (which annoyingly required T10 Torx, T10 tamper-proof Torx, T15 tamper-proof Torx, PH2, PZ1, just to access the damn transformer…but I digress!). Sure enough, the transformer had a minimum wattage of 20W. The new LED lamps are down to only 1.5W each, so I thought I found the culprit. Wiring is straight forward: switched (no dimmer), parallel wiring.

So I walk down to my friendly lighting store (a real old-school guy who stocks EVERYTHING you could ever imagine) and bought a TCI transformer specifically labeled for LED LAMPS with a minimum 2W load. Went home, put it all back together, hit the switch, and WHAM! PULSING AGAIN!!!!

Took it apart, took it back the store, where my guy pulled out a test rig of G4 sockets and we reproduced the same effect.

Anyone out there have any idea why I have pulsing in unison between these two lamps on a transformer specifically within specs for them? Anyone got recommendations for G4 LED lamps? Or hacks to make these work right?

So…defeated, frustrated and just plain tired, I put back in the original 60W transformer and tossed in two OSRAM halogen G4s. Alas, our household is now only ~95% LED.