Circline Fluorescent Kitchen Ceiling Light Replacement

December 10 2016 – the kitchen light stopped working.   This is a 20″ square fixture to replace the original which featured two “circline” fluorescent tubes, 16″ 40W (2500 lumens) and 12″ 32W (1600 lumens) and VEB82234 solid state ballast.

LED’s … looked into a Costco 14″ LED fixture at $27 but it produces 1400 lumens at 21 W-  would need three of them to light up the kitchen.

These things seem to last a few years but this is the second such unit to fail over the years -not sure how old this unit is.  Because the third time is a charm, I got a replacement from City Mill for $55.  I’m not sure exactly which component ( tube, ballast) failed but I suspect the ballast.  Searching you tube and the web, the power transistors seem to be the weak point – they get hot and burn out.  Why now?   I put the old unit on the bench and powered it up but no light.  If the fixture was in good shape I would consider a repair, replace the ballast ($20) and tubes ($20) but you can see already this $40 worth of parts, but the fixture has four broken plastic clips that hold the 20″ x 20″ plastic diffuser cover.  I’d have to find or make replacements, then start by replacing the fluorescent tubes.  Planned obsolescence? So $55 seemed to be the better bet with a brand new, returnable full replacement.

Check the transistors for shorts or opens – might as well find out.

In the failed unit, the entire fixture is down – neither tube works and both are black near the terminals, BUT they did flash a few times while I was messing with them in the ceiling – so most likely the ballast “blew out”, whatever that means – which component?  Transistors seem to be the week point.  Lets take a closer look.

A youtube video talked about the fact that certain power transistors cannot be obtained on the market — e.g. PHE13007 transistors – neither Mouser or Digikey carries them.  So they are hard to get – maybe a trade secret limited production, which is dumb … costs everyone money.

No clue.  No obvious signs of burning or leaking in the ballast – I checked diodes, inspected the caps.  I will bench check the new unit so at that time I can test the tubes.  I think the thing works with one tube down – we’ll find out.

This is a good intro to how ballasts work : http://www.homemade-circuits.com/2011/12/make-efficient-electronic-40-watt-tube.html.  There is a black art to fluorescent circuits with tradeoffs on tube life, brightness and the electronics and a lack of good information. Interesting.

One of the trade-0ffs with fluorescent tubes is that they blacken at the ends and put out less light.  This is certainly the case here – but I think the tubes are OK since they showed no sign of flicker or dimming, except now, this sudden complete failure.

 

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