Richmond Solar Beam bulb life span

[Squeeky]

Hey guys,
Just needed a clue to know when to replace the bulb on my machine?
The light sensor determines the length of time (light units) necessary to expose screens. I've been increasing the number of units (all else being equal) to expose screens during the last few months.
Doesn't seem normal.
Thanks for any advise

Jack

[blue moon]

the answer is. . . it depends. Each time you turn it on or off, it loses a little bit of life. As it ages, it also shifts the light output to a different frequency (or so I am told, but have not had the opportunity to verify). ppl I trust say to replace MH bulbs every 6 months if used daily. We have gotten a lot more out of them, but that's us. If you are having to make drastic changes to the exposure times, it is possible the bulb is going. You should have a spare anyways, so either compare the times to it or order a new one and compare the times.
How old is the bulb you have? Are you using an integrator?

pierre

[Frog]

If you are having to make drastic changes to the exposure times, it is possible the bulb is going. You should have a spare anyways, so either compare the times to it or order a new one and compare the times.
How old is the bulb you have? Are you using an integrator?

pierre

Interestingly, Squeeky posted that he has had to increase light units, something that I have never heard of, as they usually remain constant and are adjusted by time as the bulb weakens. Are integrators frequency specific?

[blue moon]

If you are having to make drastic changes to the exposure times, it is possible the bulb is going. You should have a spare anyways, so either compare the times to it or order a new one and compare the times.
How old is the bulb you have? Are you using an integrator?

pierre

Interestingly, Squeeky posted that he has had to increase light units, something that I have never heard of, as they usually remain constant and are adjusted by time as the bulb weakens. Are integrators frequency specific?

Integrators are frequency specific. There is a filter that allows only UV light in.   It sure which frequencies does it measure, but the bands are usually not that wide when using physical devices.
If he is using an integrator, it should not change enough to really notice it over a short time period. That’s why I was asking if he is using an integrator in the first place. Could it just be a timer?
Even then, the time change should not be. Sry drastic.
Pierre

[ScreenFoo]

Not sure if frequency is referring to wavelength or not here, but if so, the spectrum response info for each model of their photocell is available for all the old Olec stuff I run.
Pretty sure they used the same physical photocell for each model with different filters to change the spectral response.

As to the actual topic: 

If my bulb is going and I'm exposing a thicker stencil, I bump up the light units.
Mediocre detail, mediocre chemical resistance, take your pick. 

edit: Fixed part about photocells it sounded confusing, sorry about that.

[Squeeky]

The bulb is the probably the original MH on the SMT 2500. It still makes incredible screens. Owned it since 2011 with light to medium usage until the automatic entered the picture two years ago.
I use the integrator.
The shop is not climate controlled. So, mid-Georgia humidity in summer or lack of in winter may be a factor on light units.
Assumed the integrator controls the time based on measurements of certain light spectrum output for exposure. Though not sure.
I use a calibration bar on every screen washout. As soon as I wash it, I know what to expect when washing out art. Using 925-WR for past two years. Noticed I was losing dots that normally stay during washout. Raised light units for longer exposure time with good results.
My question is probably answered by the comment regarding a six month bulb life span during heavy usage.
Probably a smart play would be to have a spare bulb on hand.
Thanks

[Sbrem]

We've always noticed the color of the light changing, and slight under exposure as a sign to change the bulb. Not very scientific, but just change the bulb and be done with it. Ours run $150.00 (Violux 5002S) or so, but it's about 8 - 10 months between changes...

Steve