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18W SOX lamps intermittent start-up fault
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Author:  soxhead2000 [ Sat Mar 02, 2024 6:39 pm ]
Post subject:  18W SOX lamps intermittent start-up fault

Hello, hope everyone is well. I have two WRTL 18W SOX lamps which have both been running fine for over 20 years but they now both have the same problem in that they frequently refuse to start up - when they are switched on, nothing happens apart from possibly an occasional flicker. However, on other days they may be fine and switch on/warm up as normal. I have tried replacing every component I can, i.e. ballast, capacitor, ignitor, 330mA internal fuse - but every time I think they are fixed, a few days later they are refusing to start again. I normally use them with a time switch, but they behave the same way if directly connected to the mains. Does anyone have advice regarding this intermittent fault? Many thanks. Matthew.

Author:  Phosco152 [ Sun Mar 03, 2024 8:31 am ]
Post subject:  Re: 18W SOX lamps intermittent start-up fault

What brand is it?
How many hours has it run?
How many starts has it done?
When it does start, is it deep red, or a lighter pink/purple colour?

What ballast are you using and what ignitor? Have you tried a 18/20W fluorescent ballast and fluorescent starter?

It may simply be end of life, number of starts is more significant than running hours as it tends to sputter the emissive material off the electrodes. If it has been started once a day for 20 years, then its almost certainly worn out.

If it starts pink it may have run out of neon. It is also possible that the glass seals have a slow leak and it's loosing vacuum.

The chances are the tube is end of life, and the reluctant start will become permanent.

Author:  soxhead2000 [ Sun Mar 03, 2024 9:20 pm ]
Post subject:  Re: 18W SOX lamps intermittent start-up fault

Hi Phosco152, thanks for the reply. What I should have mentioned is that the tube is the first thing I tried replacing, and it has had no effect - some days the lamp will work fine, but on other days it will refuse to start, perhaps just giving an occasional flicker. The ignitor I am using is a Parmar PB018W255 for 10/18W SOX, and the ballast is an Osram BSX18-T; I haven't tried a fluorescent ballast/starter. As mentioned, these are replacement components as well as the other components; the only other thing I haven't changed is the wiring, but presumably if the lamp works well some days then the wiring is not an issue - and if the lamp can start up it will run reliably until switched off. The 'new' components I have put in are actually 10-15 years old from my stock of spares - is it possible these deteriorate over time even if they are in storage and not in operation? The replacement tubes I've put in were also several years old.

Author:  Phosco152 [ Mon Mar 04, 2024 8:02 am ]
Post subject:  Re: 18W SOX lamps intermittent start-up fault

Have you looked at the bayonet fitting, particularly that the spring contacts are moving freely and making proper contact? Many years ago I knew of a 90W fitting that would randomly not operate. I was lucky enough to obtain the lantern, and once stripped down, the bayonet fitting was found to have a duff spring contact. Mystery solved..

Author:  soxhead2000 [ Mon Mar 04, 2024 7:15 pm ]
Post subject:  Re: 18W SOX lamps intermittent start-up fault

I'll look into that later in the week when I have some free moments ... many thanks for the suggestion.

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