Quoted from Mad_Dog_Coin_Op:Ok - This is what I would do. Transistors can be bad and test fine on the multimeter. They are cheap so I would just replace any in the circuits that you are having issues with. If you tested your old school bulbs in all the sockets in question at once your problem is most likely in the transistors. If you tested the sockets one at a time and then returned the LEDs after it passed you might still have an LED issue. Gottliebs hate having LEDs in certain sockets. It causes all sorts of strange lighting problems. These problems are most prevalent in the OEM driver board. After market boards are less problematic.
Gut feel it that there shouldn’t be any sine waves anywhere. Hard to tell from the picture but looks like the “sine” wave is rectified... ie bottom half of the sine wave is flipped up to positive (by the bridge rectifier) and its a series of bumps... not a sine wave. Anyway, that signal should be relatively flat. A capacitor should be in the path to hold the bumps at the top end of that voltage with only a little ripple across the top.
So I’d say your bottom two photos look more like what I’d expect to see... flat signals with no oscillations superimposed .
If you are applying an oscillating level to the bulbs, then from “dc” point of view it will see the average of that voltage level somewhere in the middle... what is the voltage level on the dvm when you measure it when on and off?
I’d need to dig or maybe someone can chime in but I would expect all levels to be flat dc levels. Maybe not general illumination, but certainly all the stuff controlled by circuit board electronics (and I really think GI is dc too).
So... I’d check caps that are on the voltage supplies that are supposed to turn your rippling rectified voltage signal into flat dc.
If for some reason they are really applying oscillating levels to lightbulbs then I’d check ground connections between boards because the ground level will determine where the average voltage of the oscillating signal will level out at.
Hope that helps