Capacitor value in Fluoresent fixture?

Question

I have a couple of ~15 yr old fluoresent shop lights which have quit functioning. They are the "instant start" type, yet don't use a canned starter. I took them apart and traced out the wiring and found that they just use a couple of chokes and a couple of R/C's to light up two F40CW's. If I correctly traced the wiring, it looks like this diagram I scratched on the back of a piece of junk mail:

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The chokes look okay, the 150K resistors are fine, but the cheap paper/foil capacitors have been hot (scorched sides!), swollen, and one had a crack where the smoke apparently got out. My problem is there are no markings on the caps. Anyone venture a guess at what the value would be? Is the value critical?

I know, replacing the fixture would be inexpensive and intelligent, but I'm retired, on a very tight income, don't have a ready ride to the dept store, and hate to add to the landfill stuff that could be fixed. Besides, I'm a tinkerer at heart.

Thanks for any help,

DT

Joseph Meehan · Accepted Answer

I am not sure why anyone would try to repair one of those.  They are throw-a-ways.  Just buy a new one.   The modern electronic ballast are far better anyway.

Chris Friesen · Answer

Apparently you didn't read to the end of the posting, where the OP already explained that.Chris

Robert Barr · Answer

Anyone venture a guess at what the value would be? Is the value

Since conventional 'starters' (the bayonet type, 1.5" x 3/4" cylinder, give or take) do the same job with the same components, why not just solder in one of them? You'd obviously need some way to insulate the terminals, but it should work.

tnom · Answer

Try a non polarized 3 uf rated at 300 volts or more

noone · Answer

Thanks very much for the replies (except for the "throw it away" one; I'll refrain from getting up on my soapbox, lol).

I'll dig through my junk box to see if I have any np 3 uF 300 volters, but I doubt it. Most of my pile is oriented toward consumer electronics (dead vcr's and other transistorized circuitry) which mainly deal with lower, dc voltages. Maybe something in the switching supplies though.

I'd love to solder in a cylindrical starter... if I knew how to wire it. I'm quite adept at soldering electronics and a bit of heat shrink tubing will take care of the insulation. I've googled for a schematic for this type circuit to no avail. Tried lots of keywords and phrases but just couldn't find anything applicable. Would appreciate a link if anyone has one available.

Thanks again!

DT

terry · Answer

I have a supply of dual tube 115 volt 60 hertz non-electronic ballasts (the type that do not need a starter) saved from a school during a lighting upgrade. Probably too heavy to mail you a couple; cost as much as new ballasts? But a suggestion might be to see if you could find a couple of fixtures that are being scrapped at a construction site? Even if the metal is mashed the ballasts are quite robust and wires can be joined as required. I hear you. And am sure that if like me you save wirenuts, any unbroken fluorescent tube lamp connectors and anything else useful. terry in Eastern Canada

Capacitor value in Fluoresent fixture?

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