UV Purifier

How long ago was the lamp last changed?

Is there a smell coming from the control unit?

Taking the top off the control unit in subdued ambient light, is there sparking or glowing coming from any of the terminals or components when power is re-applied?

The lamp [philips 8 W ] is original supply from mfg. [ Unit purchased 10 months ago]

No there is no smell only some noise [ chit chit ] coming. The lamp is also glowing as usual.

One more question. What prequastion should i take, to start/check the uv system in dismenteled conditions. [ i. e. out of enclosure]

<....What prequascaution should i take, to start/check the uv system in dismenteantled conditions. [ i. e. out of enclosure]...>

There will be live parts at line voltages present, so these must not be touched without the risk of electric shock.

It may be that the unit is working correctly after all, and that the noise is coming from something like a mains transformer, which do rattle from time to time.

If it is still under warranty from where it was purchased, contact the supplier for advice before invalidating any warranty by breaking any seals on the enclosure.

Its been awhile, if the lamps are bad and need to be changed out, do not touch with bare hands, the oil residue left will effect and burn out the lamps....same with halogen lamps.

As a non-english speaker I know that "chit chit" would more likely be the sound of arcing (arking?), the OP should check all hi voltage wiring insulations and bare conductors that might be too close to each other.

Yahlasit

DO NOT look at the UV tube while glowing. It may harm your eyes.

Also keep in mind that the UV light emitted by this lamp is likely to be UVC which is bad for your eyes. Do not stare at this lamp while operating.

It also sounds like it is a type of fluorescent lamp (low pressure mercury vapor gas discharge lamp). That being the case, it consists of a ballast (current limiting inductor unless it is a newer electronic type) and a starting switch in parallel with a capacitor. The purpose of the capacitor is reduce noise. It may be the defective component. If the starter was defective, the lamp would fail to start or attempt to restart after it was already operating. Beyond that I would need more information.

Incidentally, in a particular failure mode, (one electrode damaged) a fluorescent lamp can actually act as a diode by allowing current flow in one direction only. It usually only does this for a short time before it reaches end of life. That can charge up a capacitor until it reaches breakdown voltage.

If there is a transformer in the circuit just check if it is O.K. It may be making such noise.