Replacing lamp socket - Super Chromega D Dichroic II head

Discussion in 'Darkroom Equipment' started by PVia, Mar 15, 2012.

  1. PVia

    PVia Member

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    I have to replace the lamp socket...does anyone know how to open this head up correctly to do the job?

    Thanks in advance...
     
  2. mgb74

    mgb74 Subscriber

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    I do remember a thread here a while back on rebuilding a Chromega dichroic head. Search around. I thought I had it bookmarked but can't find.
     
  3. Neal

    Neal Subscriber

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    Dear PVia,

    Not to worry. It's pretty straightforward. The socket wires connect to a terminal block in the back on the right side. You might be able to do it without taking it all apart, just cut the current wires and crimp them to the new ones. You could do it that way and never even remove it from the chassis.

    Neal Wydra
     
  4. PVia

    PVia Member

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    Thanks...so it looks like the back cover can be removed. Is there a special screwdriver for some of those screws? (totally green with this)...or are those regular square heads?
     
  5. Ian C

    Ian C Member

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    The screws that hold the end castings and the sheet aluminum covers together all use standard Phillips cross-slot heads unless someone changed them.

    The thing to keep in mind is that the screws are mostly threaded into shallow sections of soft aluminum. The aluminum threads won’t bear much force without tearing out the threads. So, when you put the screws back in, it’s a good idea to coat the threads with Locktite #242 REMOVEABLE Thread locker. This keeps the screws in place without over tightening and possibly damaging the threads.

    To replace the bulb socket you need to remove the right end cover (as you face the front), the rear panel, and a few other parts and screws that will be obvious as you disassemble. The upper part of the rear panel is actually a light baffle open at the bottom for the cooling fan exhaust.

    Replacement GX5.3 sockets for the Dichro II lamp house with the white woven insulated conductors and clip-on leads already installed are available from KHB in Mississauga, Ontario.

    http://www.ebay.com/itm/Lamp-Socket...677?pt=LH_DefaultDomain_2&hash=item588c925a5d

    Sometimes the existing bulb socket can be made useable by using an old bulb to clean the contacts inside the socket. By spraying the holes in the socket with tuner cleaner and inserting and removing the old bulb 10-15 times, the friction will sometimes abrade insulating corrosion or other debris from the contacts and allow the bulb to operate normally. I recommend trying this first before replacing the socket.
     
  6. PVia

    PVia Member

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    Thanks for the info, much appreciated.

    I found the sockets at ReplacementLightBulbs.com for $2.52 each...arrived in 3 days.

    Now to attempt the repair ;-)))
     
  7. Ian C

    Ian C Member

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    One way to greatly simplify the repair is to cut the leads to the old socket and make a solder joint between the old and new leads not far from the new socket. Solder joints are trouble free if done corrrectly.

    If you first slip on some small diameter rubber tubing of sufficient length to cover and insulate the joint you won’t have to worry about using gummy tape.

    If you ever need to replace the socket you can simply unsolder it. In this way you don’t have to disassemble the head to get at the clip-on ends of the original leads burried under the joint between the rear cover and the frame of the lamp house. The original leads and connectors can simply stay put.
     
  8. PVia

    PVia Member

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    Ian, thanks...that's what I ended up doing. Works perfectly...!