Do you still have this lamp? It may come back to life with more extreme methods. I grabbed a neon sign transformer specifically for this purpose last fall LOL. I did try something similar with a microwave oven transformer on a Sylvania 1000W mercury lamp and it worked!

If you put the lamp IN the microwave it might work too. I've seen a video on YouTube when a guy stuck a dead MH lamp in an old ratty microwave and it lit up lol.

You could try this on the 320W PSMH ballast from the M-400A2 I'm sending you Darren.

It was getting to the point where I could barely see my shadow under it. It was greened out a little,yeah Mike I could try it in the 320W PSMH. Yes Vince I still have this lamp,cool you grabbed a neon transformer,that might get it going. I do have a microwave transformer. I did try before to get the lamp started again,I think I tried kick starting it on a 250W MV without success.

Well if you ever decide to throw that lamp away, don't! There's a good home for it in Québec LOL.

Sure,I will keep that in mind, I will tell the lamp that a fellow collector would like to get you working again in all your glory using a special method With 12,000+ volts AAAHHHH!!

i have a HPS lamp that is so dead it arcs in the outer bulb then it jumps across the socket contacts instead making a horrible zapping noise and smells bad

Darren: TWENTY thousand! C:<

@ Aaron Is it smelling from the socket cement burning? @ Vince EVEN better!

yes i think so! is 20KV as high as the NST's go?

Oil burner transformers can generate 20kV. Come to think of it that's what I had found and not a neon sign transformer LOL.

What would that be used for?

It ignites the fuel in the burner to generate the flame. They tend to be replaced by electronic ignitors but the good old transformers are still common.

67,500 hours? What was this in use in?

I have a dead 400w /C Bonusline that's defying all my attempts at lighting it. So far I tried: a MH ballast, a PSMH ballast, and a 12kV NST.

@GEsoftwhite100watts I had it in dusk to dawn service for over 15 years in this fixture.

Joe, 20kV may do! And at this stage chances are it'll arc at least temporarily between the starting electrode and its neighbour main electrode, no matter what happened to the arctube. My first "victim" was an unbranded clear 175W mercury lamp. It seems the arctube has leaked because it'll arc on the starting resistor! The only thing I see is a tiny white bead-like thing in the quartz close to the main electrode. Maybe argon has leaked by there...

Anything over 20kV is totally useless so this lamp goes to recycling next spring LOL.

Ahh, thanks Vince! I'll keep that in mind the next time I take a crack at firing up the dead 400w /C.

Interesting, dusk-to-dawn? Was it dayburning and never turning off except for power outages or actually turning on and off once a day? Because you were mentioning trying to get it lit AGAIN...

Yep, it was dusk to dawn operation. It wouldn't light up again after being removed from service, I guess it didn't like being disturbed after all those years lol.

I wonder if something like carbon is stuck in between the starting probe and electrode, try it base up and give it a tap