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T5 bulbs dim and inconsistent

JohnJL

Well-known member
Joined
Jul 28, 2010
Messages
150
Location
Toronto
I bought two fixtures to compare light, electrical interference and looks.

One is from the Despot or Loose (forget which), 48" 4x32w T8 bulbs. At first two tubes were uneven but after burning in for a few hours they are all bright and even. It fired fine at ~3 degrees C and no static on the radio I placed right on the ballast...this light has a prism diffuser, required hardwiring and does not include the mounting hardware.

THe 4-lamp llight from princess auto is wider and has a steel grate guard. THe body is made of diamondplate aluminum, comes with 4 T5 28w bulbs, has an integrated external outlet, a pull-cord, and has a plug. Also includes chain and hanging hardware. It also fired no problem and made no static when a radio sits on top of the ballast.

They are both the same price. THe wider spacing of the T5 bulbs gives a broader light pattern and the steel grate wont accumulate dead flies like the plastic prism cover in the HD/L's model. The price are exactly the same.

I would be an easy choice except the problem is 3 of the 4 T5 bulbs on the diamondplate light only light up halfway. THey are half-dull. No matter how I switch the bulbs around, the same 3 are bad and the 1 good. I triefd letting the light run for ~10 hours, no difference.

Its been a blizzard here today so I didnt get a chance to go out and buy some more T5 bulbs to compare. The lamps came with the light and are "FSL" brand 28w.

Is it common to have a high defect rate in (presumably) cheap T5 bulbs? I have ~1500 sq feet at 12 foot ceilings and 20 junction boxes wired in so I dont want to buy 20 fixtures that need to come down again...

What do the boys think?
 

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rockwithjason

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Jan 8, 2006
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2,633
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Las Vegas
looks like you might have a bad connection at one or more of the tomb stones. they use the cheap push in connectors and are forever a problem with most fixtures
 
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JohnJL

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Jul 28, 2010
Messages
150
Location
Toronto
I think it is the bulbs...I've switched the bulbs around in different positions and it is always the same bad ones.
 
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Falcon67

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Jun 11, 2009
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18,371
Location
Merkel, TX
>Is it common to have a high defect rate in (presumably) cheap T5 bulbs?

I dunno - I just bought 4 "100w" CFL bulbs for closets here and two of the 4 were DOA. Not a very good omen LOL.
 

tfi racing

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Apr 19, 2008
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2,907
Location
Cedar,BC
Which fixture has the ballast that you posted a pic of?I would stay away from that no name unit...
 

nehog

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Jan 2, 2010
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Location
Jaffrey, NH
I think it is the bulbs...I've switched the bulbs around in different positions and it is always the same bad ones.

Just to get wicked technical, when you say 'same bad ones' it is unclear as to what 'ones' refers to: the actual bulb, or the bulb position in the lamp. :)

If the bulbs (say you marked them 1, 2, 3, and 4) are bad in any position, then I'd agree the bulbs are possibly defective. However it may be that the one that lights is simply 'better' (strikes at a lower voltage) than the other three, that the ballast is bad, and that in fact the other three are OK.

I guess if you were willing to try, three (or four?) new bulbs is a good starting place, however I personally think there is a possibility that the ballast is defective.

Maybe make sure you can return the new bulbs if they are not the problem?
 
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