I currently have a Mole 5K
Fresnel on my work table, I”m changing it into a prop light that houses 3x
Pixel Pup
LED lights. Gee, some advanced notice will have been nice - this given it got where I work yesterday and leaves Friday. This in addition to a very busy schedule, I hope I can replace the broken off
gel frame clip on time. On the other
hand the
fixture came with a full set of screens to it,
barn door, tweko mounts and what seems to me a first era type DPY
halogen lamp. Very much different than any modern DPY lamp, and not
incandescent. Just got added to my wall of shame. On the other
hand, as very common to old Mole Fresnels, yep, had
asbestos wiring and a broken lamp
base - them are not cheap. Also normal to such fixtures is an
asbestos tape around the
lens, a possible need to replace the bearing on the
yoke cam, a need to replace the
yoke cam pad and oil the heck out of all fittings and especially pivots. After that, should work perfect. They are tanks and it doesn’t matter how old it is.
Biggest problem with such a
fixture is in the lamp
base. Even if the more recent
porcelain type that doesn’t break as easily as the pressed fiber type at times with an
asbestos pad, your sockets are often toast. Easy enough to clean them up in re-surfacing with a dremmel tool and special deoxidant or electrical cleaner/lubricant but most often what you get used is toast and needs good attention. 75% of the time, the
porcelain brackets that hold the lamp
base are broken however, expect to pay for new ones. The lamp
base type is unique to Mole Richardson though I have seen this part with a Warner Brothers stamp on it also which is just as good. Good concept for retaining the lamp though at times there will be a steel/aluminum corrosion problem in the
thumb screw assembly for retaining the lamp. Replace such parts such as the
bolt with a stainless steel or grade 8 one and that will go away. Make friends with TriFlo lubricant, good Teflon oil for all assorted parts or joints in the
fixture. Replace what screws are corroded or rusting also. Oil only helps so much. Most likely necessary to replace all wiring, crimps and
terminal nuts/washers. Replace the wiring with 250c TGGT wiring inside the
fixture - any good cable supplier or McMaster will
stock or be able to get it. Replace all
crimp terminals if wiring is replaced with high temperature ring terminals that have fiberglass electrical tape over the
crimp, and replace all nuts, washers and lock washers as necessary or not looking in good condition with brass or silicone bronze nuts or washers. Don’t use normal hardware or crimps, nor under 250c
wire inside a 5K or larger
fixture.
Mole Mauve as a spray paint is available
thru Mole Richardson or any distributer that can get their gear. It’s advisable to use it both for high temp. and color match. Most likely you will need to clean the
fixture really well and scrape and sand anything that’s coming up if it is. Paint the bottom also, it shouldn’t be silver.
Painting isn’t a bad thing if you plan on using the
fixture. Keeps steel parts from rusting & aluminum parts from corroding due to conditions and heat. Also looks better and good looking gear gets more care to it than gear that looks like it don’t matter how many times it bumps the ladder on the way up.
For the most part this type of
fixture will have been replaced by the soft light, but given frosted lamps & perhaps some frosted
gel to boot, should make a nice
wash light. Can even buy some
Mogul screw to medium screw adaptors and lamp it down, or use 300w mog screw lamps in it.
While shopping, you might get a baby spud to
C-Clamp adaptor to hang it from. Such would be available from Mole or
Altman or most other movie lighting companies. This will allow you to hang it from a
C-Clamp. Hang it from a heavy duty
C-Clamp, Mole fixtures are heavy. Otherwise a Gr.5 hex
bolt 1/2-13x4.1/2" with USS washer and spring lock washer when using a T-5700 Doughty clamp will work, or a standard half cheseborough with a similar length of alloy grade 1/2-13x4.1/2"
socket head
flat head screw would work in it.
Get a chain or 3/16"
wire rope safety cable also, a
bit more heavy than you want for a
stock 1/8"
wire rope unless Euro style that uses thimbles such as available
thru Robe. That rope with
dog clip on it is for hanging the cable or latching onto
gel frame or
barn door not a
safety cable. Most likely it’s fine but might need replacement.
The “high temp rubber” cable off the back of the
fixture is normal 90c type SO
wire and not high temperature. It’s common to use extra heavy duty cable feeding
power to such a
fixture given the wiring area is separate and away from the heat. This said, check the condition of the cable feeding the light for dry rot, should be able to read the markings in brand,
gauge and type on the cable & it should have not cuts. Cut the
whip down to six feet - this way if there is a problem as standard practice in an emergency you can just unplug it. Check inside the
fixture also to look at the cable. First it should be grounded - often the
ground wire bolted to a mounting screw for the
switch, second that it’s not heat damaged within the wireway. Shouldn’t be brittle or discolored. Easy enough to replace as needed.
Pound that ding out of the rear of the
fixture - looks bad and won’t help it’s looks. Check the tightness of all screws holding it together. Don’t persay remove them unless necessary, but they want to be tight. Should they be really loose or corroded, clean and oil, add a lock washer and
thread locker or replace and add threadlocker. Zinc for most parts on the
fixture in screws is fine though stainless steel is better all around for high temperature and especially for any steel to aluminum connections.
As above, your internal wiring and lamp
base are probably toast (your photo shows different for at least a really good clean lamp
base). In the wiring you could use SF-2
wire of at least 16ga feeding the lamp bases. TGGT would also be fine. Feeding the
fixture you need at least 12ga type SOOW cable. Again with the above high temperature ring terminals, grounding, high temperature fiberglass electrical tape over the crimps and replacing as needed from lamp
base to nuts/washers as needed. Most likely your switches are just fine and look good by the photo. Very rare they go bad in such a
fixture. The purpose of the switches is to
switch off one or both lamps without unplugging. Remember for a movie shoot, dimmers are not much used. Want to dim the light,
switch off a lamp. Want to un-plug and move,
switch it off first. For
stage usage, it’s ok to bypass and even remove the
switch - often done - nothing more frustrating than the rig in the air and finding out someone flipped a
switch by mistake, this after walking the
truss with a replacement lamp.
Should you bypass the
switch, while code says nothing large enough to fit a finger
thru should be a hole into the wiring area large enough to stick a finger into, I wouldn’t plate up the
switch hole - this would destroy the original antique
fixture. Leave the switches where they are, there is enough room around them for your splices. You should
knock out seal
plug any extra holes for the wiring if there was extra single
conductor holes cut but for the switches consider them protected enough. High temperature
crimp a
butt splice the SO cable to the heat
wire, than wrap it in fiberglass electrical tape. Otherwise Ideal sells some high temperature set screw
wire nuts for connecting from
cord to dual
switch. You would want some eight
gauge ferrules to first insert the
wire into before using such a set screw
wire nut, but this would be acceptable for making the splice. Put a band of fiberglass electrical tape around such wires 1" from the
wire nut to act as
strain relief and hold together the wires. All of these parts are McMaster Carr of course.
IF the
fixture is not grounded, you need to make it so. Often the best place for this is near the
switch or lamp
base mount. IN this case one of the screws holding the
switch should be sufficient to do a
ground to. Again with lock washers and replacing bolts if bad. For a
ground, zinc plated steel hardware if fine.
Photo of your lamp
base looks like it’s in good condition, at very least on that one, hit it with a set of brass
wire wheels or fine silicone fiber abrasive wheels for the Dremmel tool and clean them up, than coat them in the above high temperature deoxidant or electrical contact cleaner/lubricant. Check screw
terminal etc. this given the
asbestos wiring needs to go. The
switch type is what I though it was - normally bullet proof and not to be replaced. Once in a while some of it’s
circuit board like mounting plates if used will go bad, and guess what is the replacement for such a
circuit board type material? Contact cleaner at most is all that’s needed. Replace the screw to the
switch, add a external tooth lock washer both brass or silicone bronze, replace the wiring and that’s all you might need to worry about. This besides the
insulator pad under the lamp
base if one is used. Often that’s
asbestos also. McMaster sells a
ceramic fiber 2" tape in various thicknesses which works as a really good replacement.
After the repairs - lots more details... just inspect any bad lamp every time you replace it. If corroded, pitted or showing especially on it’s center of lamp
base contact damage, pull the
fixture from service and give attention to the lamp
base pitting due to bad contact. Once a year pull the
fixture from service, inspect it’s
base and wiring, oil what’s needed and all should be good to go.
Should be a great dependable
fixture.
Final note, the bearing in the
yoke clutch and the fiber clutch pad might need replacement also. Try oiling up the bearing to see if it can be saved but if toast, it’s either
thru Mole for the ½" shaft, 1" OD and I believe ½" thick bearing or a special order
thru McMaster and waiting a few weeks but they can also supply it. Worth it as with cleaning, tapping and oiling all
yoke hardware. The fiber pad you can cut yourself out of various types of high temp low friction materials or buy. Graphite is often used as with other materials. On the opposing side of the
yoke mounting is going to be either a shoulder
bolt or a hex
bolt with lock washer, washer and a
conduit like sleeve. If this hex
bolt has a “R” stamped on it, it’s I believe origional to the
fixture, re-tap, oil and don’t replace it. Otherwise I would go with an appropriate shoulder
bolt.
Thread locker what ever the end result is necessary in this area and this is the side you want the
safety cable on.
IF
gel frames and
safety screens came with the
fixture, cool. Otherwise it should be easy enough to fabricate some.
Gel frames can be welded out of thick banding material, this hinged with a piano hinge or left two pieces. Might drill holes in it and do some thin
gauge tie
wire in a 3" support for the
gel or it will sag or burn. Beyond this, you must
safety screen such a open faced
fixture - this if used at anything over like 150w. To do this, do a
gel frame with 1/2"
hardware cloth or 1"
chicken wire welded or rivited between. Very important the
safety screen. This or
safety coated / dipped lamps.
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