new buzzing sound?....

[shuggy4105]

I have a dual 400w HPS/MH magnetic ballast and lamp which has started making a strange buzzing noise which seems mainly to be coming from the lamp itself. Its the same one I`ve always had and has always worked flawlessly. I run with HPS always. I don't want to replace the ballast to find its the lamp which has the problem. It isn't continuous buzzing either, it comes and goes. This set-up is silent in the normal run of things.
Anyone have any experience with this?
FYI SnowRyder autos on 18/6 schedule.

 

[trillions of atoms]

did you cut all the fans of and everything else that makes noise and then you started hearing it ?the lamp will hum and make some noise. I never really noticed it until one day I went to the service one of my fans and cut everything off other than the lamp and heard it. I would always hook up the light to the same circuit as the circulation fan and both would come on at the same time and I didn't notice it for years. Older bulbs will make more and more noise too as it ages. I don't know if it's time for you to change your lamp but if you had it running for several months might be a good time.


sounds like an old or cheaper bulb.

 

[Hushpuppy]

Yes I agree with it possibly being an older or cheaper bulb. The ballast produces electricity at much higher voltage for firing the HID bulb, and this voltage is produced at a certain(very high) frequency that is different from the 60Hz of standard "wall current". Over time this high frequency will cause stuff within the circuit to come loos and vibrate, creating the hum. Early on the hum can come and go with the change of temperatures, but as it ages, it will get progressively worse until it either creates a failure or until you get annoyed enough to change it. These vibrations are also what cause the ballast to buzz or hum.

Street lights are notorious for this as they are cheaply made. Cheaper ballasts have transformers that aren't held together well and will get loose and vibrate. Electronic ballasts don't have the big steel core transformer and their frequencies are much higher so that their harmonics don't affect the conducting materials as much, but sometimes they can have the same issues.

I would start with the bulb first and if that doesn't fix the problem then I would say the ballast is beginning to die and needs to be replaced.

 

[DrFever]

i would look at your ballast ignitor or capacitor is getting weak

 

[shuggy4105]

thanks bro`s, I`ve ordered a 600w set-up as its now day 44 from seed and these autos have very little to show in respect of calyx production...vegging like crazy though, makes me wonder how well the auto trait has stuck with this strain.
DRFever, what am I looking for exactly? The buzzing has gone for now, maybe it was always like that TOA, the fan was off when I noticed it first.