Whelen Alternating Flasher Model F

[JohnMarcson]

I have this Whelen 120vac flasher box that is advertised as an alternating flasher. The two lights flash simultaneously, which I never thought much about. I opened it up today and noted that the two bulbs are connected together (in back not shown) and the second white wire is missing from the output side of the flasher. The plug has yellow, red, yellow on one side and white, green, missing on the other side of the plug. That missing white wire has been connected between the two bulbs. i haven't tested that side of the flasher yet, I'm not sure if it failed and they were ganged together to keep it working or if this was an intentional option. I may meter it a bit later, but it is still and interesting item.

 

[RS485]

He he -- if I were you, I'd stick a tiny screw driver in the connectors to bend in the detent on the pin of the white wire so as to able to pull it out of the housing, swap it to the other side and see if the "channel B" produces the same behavior (that both lamps flash in unison). If it works, it strongly suggests this was a factory mod for a customer. If it doesn't then it's a PCB in need of a fix!

FWIW, the SCRs are still available on eBay right now (not that this component is the problem, per se):

 

[JohnMarcson]

He he -- if I were you, I'd stick a tiny screw driver in the connectors to bend in the detent on the pin of the white wire so as to able to pull it out of the housing, swap it to the other side and see if the "channel B" produces the same behavior (that both lamps flash in unison). If it works, it strongly suggests this was a factory mod for a customer. If it doesn't then it's a PCB in need of a fix!

FWIW, the SCRs are still available on eBay right now (not that this component is the problem, per se):
View attachment 241006

I will give this a go. I am on the fence with this one, it looks pretty neat and tidy, but it seems like an odd way to factory modify it.

 

[kitn1mcc]

See the sign setup we had two here in town here at the fire house in red for when the trucks were coming in or out