I have just bought an old 575W HMI fresnel with magnet ballast. It is working fine but the double ended HMI lamp have a bit of black desposit on the glass and obvious burnt ends of the electrodes. The colour temperature has shifted below 5200K. I read somewhere that you shall replace the lamp after half of its life span becuase of colour temperature shift and the increased risk of explosion with lamp reaching the end of its life. Now I don't know how many hours the lamp was used previously, I wonder what other signs I shall look for before I replace the lamp?
When you change the double-ended HMI lamp, is it necessary to position the lamp so that the electrodes are in the correct orientation and why? I ask this becuase there is a warning diagram on the front of the fresnel and the lamp was already not positioned correctly by the previous owner( a film company).
If the focusing mechanism of the lamp become stiff, do i need to put a little lubricant oil to the mechanical moving parts or i shall leave them alone? Will the high temperature inside the lamp vapourise the oil and form desposit on the glass of the lamp, affecting the life of the lamp?????
Final question, can you connect HMI head with SE lamp designed for electronic ballast to a magnet ballast? I have seen DE lamp heads are being mixed with magnet ballasts made by different makers.
thanks in advance
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