How to interpret fluor. tube colors?

The fluorescent lamp on a Kenmore Model 250 stove (now

20 years old) has started wrecking new fluor. tubes (Sylvania, 22-inch, 18 watts). Symptoms are:
  1. Dark grey bars appear at both ends of the new tube within 5 min. use.
  2. Tube lights only at the two ends (dark in the middle for 18 inches.) One end shows white light, the other pink light.

What does this mean?

Reply to
Don Phillipson
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Hi, The tube is worn out.

Reply to
Tony Hwang

Starter/ballast gone...

Reply to
dpb

No - New tubes don't go bad that quickly. Sounds like the starter contacts are shorted closed and not openiing after a few seconds like they are supposed to. The warm glow seen by the OP is the heaters staying on because the starter contacts are staying closed more than a few seconds. The blackening is due to the filament material being burned off by the filament staying on. Normally, only a little bit of material gets burned off each time the light is started. When the filament stays on ther material gets rapidly burned off and deposits on the cooler glass where is turns dark. I'd bet a lot of $$ on a stuck starter.

Reply to
hrhofmann

Don:

I'd phone Sylvania's 1-800 customer service phone number to see if they've had a problem with their small fluorescent range tubes and see what they say. Maybe talk to their tech support people and tell them about the dark grey bands.

Any leakage of oil from the ballast is a sure sign that it's kaput.

Reply to
nestork

Do I read that you put a NEW tube in, which gets grey ends in a couple minutes of being new?

That's a new one, to me, if so.

Christopher A. Young Learn more about Jesus

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20 years old) has started wrecking new fluor. tubes (Sylvania, 22-inch, 18 watts). Symptoms are:
  1. Dark grey bars appear at both ends of the new tube within 5 min. use.
  2. Tube lights only at the two ends (dark in the middle for 18 inches.) One end shows white light, the other pink light.

What does this mean?

Reply to
Stormin Mormon

If the tubes grey-end in five minutes, that's my diagnosis also. Starter stuck.

Christopher A. Young Learn more about Jesus

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No - New tubes don't go bad that quickly. Sounds like the starter contacts are shorted closed and not openiing after a few seconds like they are supposed to. The warm glow seen by the OP is the heaters staying on because the starter contacts are staying closed more than a few seconds. The blackening is due to the filament material being burned off by the filament staying on. Normally, only a little bit of material gets burned off each time the light is started. When the filament stays on ther material gets rapidly burned off and deposits on the cooler glass where is turns dark. I'd bet a lot of $$ on a stuck starter.

Reply to
Stormin Mormon

The fluorescent lamp on a Kenmore Model 250 stove (now

20 years old) has started wrecking new fluor. tubes (Sylvania, 22-inch, 18 watts). Symptoms are:
  1. Dark grey bars appear at both ends of the new tube within 5 min. use.
  2. Tube lights only at the two ends (dark in the middle for 18 inches.) One end shows white light, the other pink light.

What does this mean?

Reply to
WW

Something here on the topic of fluorescent tube failure.

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Reply to
harry

If you there is a starter and if it is stuck both ends should be kinda pink from the filaments. You might evaporate the filament to blacken the ends.

For ballasts that power the filament, if a filament opens (or bad contact to ballast) you can get end blackening at that end. The tube would light, and 5 minutes sounds real fast.

My guess would be starter (if there is one), contacts from ballast wires to socket and socket to tube, then ballast.

You could try sci.engr.lightning. Some real smart people. It is pretty dead now, but some of the regulars seem to still be around.

Reply to
bud--

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