A year or so back, I bought a dozen GE EJL (I think that's right...I'm not at home as I write this) bulbs for next to nothing on eBay. I go in streaks of very good life and then, like last weekend, I blew 3 in a day. I vaguely recall reading somewhere that corrosion on the bulb pins can cause problems. These bulbs all appear to have more surface corrosion than normal (certainly not shiny and fresh). Does anyone have any insight on this?
Well Craig, my Beseler Dual Dichro head has a QEJ bulb which is a 24V bulb. The EJA bulb is a 21V bulb. If you are using these they are probably blowing because the voltage is not right. Also, the QEJ is 200W and the EJA is only 150W, so the QEJ will be brighter. BTW, I've not had to change the bulb yet and I have had the enlarger for almost a year. Hope this helps.
Corrosion of the bulb contacts will cause the bulb-holder contacts to overheat, corrode and weaken thereby exacerbating the problem. Best change the holder as well using a bulb with clean contacts.