Compact Fluorescent Failures

If they don't have a thermal fuse, they probably have a fusable resistor. And, yes, you should replace the safety devices!

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I have seen a few with really bad soldering. The switcher transformer almost fell out of its holes. Also something blew the FETs on a few. They haven't failed again since I changed the FETs and fuse.

I had one with bad solder joints that I repaired and is still working.

I had a few where the starter filament on the CF tube went. I have not had one last anywhere near 7 years. They are used outside and on all night every night.

Anybody know how much it matters if they are mounted base up or base down regarding both light output and relibability. Base up seems to work better but I don't have any real data.

Mark

I've heard it's a large electro (often in the base of the lamp) which is often the fault.

NSM wrote: ...

I can vouch for that being the case in one of the failures I've observed

- end actually blown out.

After the posting regarding the poor soldering, I've found some very dodgy looking joints on one of the units; I'll re-flow them and see if that works - before I continue testing the components one by one.

Cheers

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My number one common failure fault finding is the units raw B+ filter cap(s). They inherently have to be mechanically small to fit within the cramped casing restraints. [Seems like someone mentioned one venting on them...hopefully with a....BANG!!!... like mine did.] Therefore, that tends to have them at woefully smaller values than could be optimal. They really take a hammering from the ~40 khz operating frequency repetitions of squarewaves. If you have facilities/capabilities of doing an ESR test on some used units you should find them onsetting to high ESR levels in a hurry. Not having that, just a running of a unit (open cased for access) for a warm up period of 10 minutes and then totally disconnecting from AC power and subjecting to a finger tip temp/warmth test should reveal units that are in ESR excess. (Will be quite warm or hot/versus just cool.) Also one could make connection across a cap at a time with a clip leaded AC voltmeter for a ripple test, bet you will find it quite high with their selected (necessitated?) values of caps.

Some units that I did enact a repair upon , ended up in a location that physical width provided no restraint, so I utilized healthier cap values as well as 105deg temp ratings (for sure). The new caps then extended thru 2 holes of the plastic housing with epoxied plastic insulative "warts" encasing their slight protrusions. 4 years and counting now.

Aside from what you've already checked, I've had a number of lamps with shorted mylar caps in them, other times one of the cathodes will open so check those for continuity.

Some have fusible resistors instead, if there's any sort of protection, replace it for sure. If there isn't any it wouldn't hurt to add a low value fusible resistor but they should all have something.

Not worth it, the MOVs will cost more than the lamp generally.

Exactly, I *always* try to repair them when they fail, it's a simple excercise if nothing else.

Most of them are rated for 6K-9K hours. The 7 year figure is assuming a few hours a day as you'll see in the fine print. Even so, a standard lamp only lasts about 1K.

This will depend on the design of the lamp, base up is likely to work better at least on the spiral lamps because the dimple at the end to control vapor pressure will be the coolest point as designed, base down it'll be hotter.

I've bought them at the (US) dollar store (rather a cold phosphor). At a buck each I don't fix them.

In another, the electrolytic capacitor

I have gutted a couple Philips lamps with an LBA202(?) SMT IC. Little else of interesting components in such a lamp... All the rest (far Eastern, as well as European made Osram and Sylvania) using a couple transistors in a power oscillator circuit. Of the several (must be more than twenty!) I have gutted the electrolytic most often has failed. I changed it in one of the lamps, which held more than six months afterwards. The lamps which show darkening of the FL tubes are nothing to keep, they probably are at the end of life. I have seen exploded transistors, but only in a couple of the lamps. They are small video output transistors in a 'long TO92' case in the far-East imports. I collect the ferrite toroids and the hi-voltage caps after measuring them. Some are nice replacements in tube gear.. The caps are marked with values and are nearly always within tolerances.

Electrolytic. It dries out from high ripple current/high temp in the lamp.

Some have only a glass-cased fuse in one of the socket wires, some have fusible resistors. I have seldom seen temp fuses.

Stein

I've really grown to like those cold phosphors, especially the daylight ones but most everything around here is yellow 2700K.

Yeah they're not really economical to fix from that standpoint but it is kinda fun, I always at least take a crack at it when one dies.

It's funny, I'm always hearing about this problem but somehow I have yet to ever run across a single one in which the lytic checked bad (ESR meter) or blew, I know it's coming but so far never had that happen.

Hi...

Durn, I've been using them for about 10 years now - don't have a single incandescent left in the place - but never yet had one fail. Mostly Sylania; but a few Globe badged. Did throw one away because the light output had dropped too much.

Waiting to fix one :) Downside is that looking at them, I can't imagine how I'd getting one apart without destroying it. Is there a trick I can't see?

Ken

The name brand ones do tend to be more reliable, as you say the lumen depreciation will nessessitate replacement before a really well made one completely fails. The problem is the name brands are rather expensive so the cheap Chinese junk sells, admittedly my house is full of them.

Some are easy to open, some aren't. Most of the ones I have will pop apart with a scredriver at the seam between the upper and lower section of the ballast housing.

...

Haven't had one yet that can't be opened with a screwdriver like James says; of course, you do need to pick the right screwdriver ;-)

Cheers

Matthew Smith South Australia

apart

They may be quite different in Australia, dunno. Most of the ones I've opened were either Feit or Commercial Electric. I have one right here awaiting a look, it's a TCP #18814/31, which is a somewhat hard to find

Start by cracking off the metal base - should be easy.

I have found _some_ good electrolytics in the lamps,maybe 10 percent of them. I measure ESR (some caps measure about right cap. value, but has high ESR (>20 ohms at 50kHz)

If you're really lucky, failed ones will pop themselves apart along the seam, to facilitate you repairing them. It's a design feature, I think :)

A couple of ones I've had have failed like that: A loud bang, a smell of burnt toffee/toast, which seems to come from the epoxy-like substance used to seal inside them. Yum. Obviously the crack in the side let the smoke out ... not opened one yet to see what went.