Why did my $8 150w enlarger bulb blow after 5 seconds?

greenspun.com : LUSENET : B&W Photo - Printing & Finishing : One Thread

I live in Mexico where the current ain't that steady - the lights often flicker as if the neighbour were building a monster... I recently put a new plug, light socket, switch and cable on my ancient enlarger - a `Gnome'??? to convert the bulb socket from the British type. Stuck a large Durst 150w screw socket bulb on it and it fused after about 5 seconds. Why? Do modern enlargers have some special gadget on them so that high wattage bulbs don't fuse? Can I not get away with putting together my own cable, etc? Anyone live in countries with similar surge problems? Help! - I want the bright bulb so I don't have to expose for 40+ seconds...cheers Greg.

-- Greg Brosnan (gbrosnan@infosel.net.mx), May 07, 1999

Answers

Greg! Isn't Mexico on 220 Volt current like Britain?? If so, and the bulb is rated at 110, then it will burn up real fast. You may need to buy a step-down tranformer, ie. 220-240 to 110-120. Make sue that it will handle the 150 watts required by the lamp. Consider a 200 watt transformer. They aren't very expensive and are readily available in most metropolitan areas. Do they have Radio Shack there? Good luck.

-- Michael D Fraser (mdfraser@earthlink.net), May 07, 1999.

Greg, try buying a globe at the local voltage, it's cheaper than a transformer. Philips make enlarger globes for 240 volt service in 75, 100 and 150 watts at 240volt. they are available is BC os ES, E27(us screw) base fitting. Your local phtographic dealer or the place that sells projector globes will have them

-- John Young (youngs@vicnet.net.au), July 29, 1999.

Greg, Another suggestion to supplement the right bulb. If your voltage is not reliable, and it goes up and down, invest in a voltage regulator/conditioner such as is used for computers. You can get one which will stabilize the voltage over a fairly good range, as well as prevent nasty voltage spikes that can shorten bulb life (if they don't short the bulb completely) and mess up your contrast and exposure times - especially if you use multigrade paper. To get one adequate for the enlarger will probably cost about $100 - $150 US. I don't know what the cost would be in Mexico, but if you have voltage problems and can afford it, it will be worth the investment

-- Richard Newman (rnewman@snip.net), July 29, 1999.

Moderation questions? read the FAQ