Replacing ballasts with different brand

[Signsforwhile]

We recently serviced an old pylon that had three Allanson 4120 ballasts on it, wired in series. Our supplier only had Signa Universal 4120 ballasts in stock so we used those for the swap. All diagrams match and wire colors and specs across brands. 3 weeks later, tonight, customer sent video of sign steady on, steady off. Not a flicker, but a deliberate on and off.

Sign contains 12, 117" HOFLOs. Could it just be a bulb out? A bad one in the batch?

Or can you not wire all types of ballasts in series?

 

[TonyC]

I prefer Allanson ballast. I have replaced several Signa ballast, installed by other companies, which did not seem more than a year old.With that said, you cannot wire ballasts in a series. They are wired in parallel. This means ( on the primary side) all the white wires to the neutral and all the black wires to the hot. Also be sure the ballasts are grounded well.If this is not what you mean by "series," I would replace all the bulbs, if you haven't already, and check all electrical connections.

 

[Signsforwhile]

They are wired in series on the secondary side.

 

[J Hill Designs]

not sure what you mean by series, but each ballast should be running only 4 lamps