400w HPS acting up need advice....

My light seems to choose when it wants to work.Some mornings it has engaged except there is no light,just some minor,blueish electrical arching down the inner tube while near the tip of the bulb(inner tube)there is more of a orange red arch.If I unplug it for 10 min it sometimes works but sometimes have to do this a few times.Just wondering if anyone is familiar with this and what it might be.Ballast,bulb, wiring...??Any help ids greatly appreciated,dont wanna have to get a new one just yet....

....nothin' huh?....

just wanna be clear...could be dangerous right....might just need a knew bulb and haven'
t been gardening long enough to have ever seen a HID light burn out...

Is it a magnetic or digital (electronic) ballast? Did you buy it new or used? Lets start there, cause it almost sounds like a bad ballast.

it's a magnetic ballast.It was actually given to me by a friend and I used it for the last few weeks of flower last round for side lighting...worked well.just acting funny now.story is,just moved....timed my garden right so I moved with 2 clones of my best strain.(nobody has ever really moved until you move your garden with no help cause ya cant tell anyone....)1 I am keeping as mom,the other I am flowering (cause I am low on medicine) with this light(after taking several clones).My only option is to use my 1000w for 1 plant which is ridiculous I think.400 w hps for 1 plant seems to much even(or rather a waste of light usage)but I gotta get some production going here.My fluorescents are tied up in veg room...(dont wanna flower with those anyway) Would anyone use a 1000w hps to flower 1 plant?seems crazy....If it's a bad ballast is it something I could repair???or time to go shopping?again?haha....always!The folks at the local hardware store are loving me this last year!Any way thought I woud throw down my scenario,see if anyone has some advice.Thanx!

....and if a bad ballast,why would it still work sometimes?

It worked this morning....unreliable tho and a pain in the ass!

It's the bulb, as the bulbs wear they build up resistance until the point where the bulb will not fire up. The blue arching is the ballast trying to strike up the bulb, but can't do it.

I'd guess the bulb is probably had it's last few days.

If it worked earlier and not now if could be because it was still warm...once they turn off they need to cool down before firing back up.

replace the bulb, if that works presto your all set

if it dosent, move on to next possibility and you have a spare bulb in case something happens later down the line or with a new unit.

sounds perfect guys,Thanx!Kinda what I figured but ya never know.....now to replace my light in a town that has a box of all-purpose miracle gro and a bag of soil from 1995 as it's garden center!