[pure-silver] Re: ELC bulbs failing in D2 Dichro Head
- From: Georges Giralt <georges.giralt@xxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 16 Jan 2008 11:56:22 +0100
Selon J Stewart <jrstewart8@xxxxxxxxxxx>:
> Folks, can anyone help me troubleshoot reasons why my lamps are blowing out
> within a few seconds of turning on my Dichro II color head (on a D2). I'm
> using the standard D2 power supply with stabilizer. The stabilizer fuse is
> intact. The power cord is plugged into a surge protector via the timer. My
> house has always had a stable power supply.
>
> The bulb elements are breaking. The problem began immediately. A bulb I had
> been using for a couple years fractured. When I put a new one in, it burned
> out within seconds. I repeated this with a new bulb and the same thing
> happened. One bulb actually broke the reflector in the process, but I'm not
> sure it was caused by the same problem.
>
> I have a voltmeter to check current to the socket if you can help me
> understand what I might be looking for in isolating the cause.
>
> Thanks in advance.
>
> Jim
Hi Jim !
If IRC the ELC is 24 V. As the power supply is stabilized, it could be that it
went south and deliver way above the 24 volts needed. This is easy to check, and
will not need a bulb.
Put the leads of the tester into the lamp socket and turn the enlarger on.
You will get either 0 V (if the stabilized output stage use the bulb as a
polarizing device) or a voltage. If it is above 24 V you've got the culprit. Be
sure to check with DC and AC voltages (you may have an AC voltage mixed with the
DC output, the sum of the two being above the 24 V).
If this gives you hte impression that the power suply works fine, check for the
bulb base. These sockets use small diameter pins and oxydize quickly causing
spikes and sometimes sparks.
Sometimes this make the lamp burn. Change for a high fgrade one (go to the
lighting store the biggest you can find in your town) and plan to change this
socket once in a while..;
Hope this will help !
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