AIEL Shop Tips
The ellipsoidal or profile spot (often, and erroneously,
called a "leko", unless it's a certain Strand model
range) is a favourite light of the theater. It
produces a sharp or soft-edged beam via
plano-convex or step lenses that are able
to be shaped using internal shutters. Patterns
(gobos) can be projected with this fixture. Typical
wattages are 300 to 1000, but can go outside of this.
The ellipsoidal is the most problematic of the basic lighting
fixtures when it goes out of alignment, and it usually suffers
the most from lack of maintenance. This is due to the complexity
of the fixture compared to a PAR or fresnel.
Instructions here will lead you through the complete refurbishment
of a typical, non-LED ellipsoidal. However, you might only need
do a part of what is outlined here, so simply skip to the pertinent
section(s). Also, you may have to modify these instructions to suit
your manufacturer's fixture.
INFORMATION BELOW MAY NOT BE REPRODUCED
WITHOUT PERMISSION FROM THE AUTHOR ©
Be aware that neither Atlantic Illumination, nor its owner or
employees will be responsible for any problems encountered as
a result of adhering or not adhering to the procedures here. This
is strictly a guideline. You must decide the suitability of the
following, and must be responsible for the results of your work.
Read through this article before starting so you'll have an idea of what
is required. You may find that some steps are better done out of order
for your particular model. Make notes or drawings as to what parts are
associated with a given procedure. It also does not hurt to have an
assembled fixture available as a reference during the later re-assembly
of the light being overhauled should you not be familiar with the particular
model on which you are working. Also, you may wish to print this page and
use it to check off each step as it is completed.
Set up a work space with proper lighting and the tools required. See
our Work Area Setup article to help with this.
Have some numbered containers or a muffin pan available in which to place
the parts from each phase of the disassembly. This will be of benefit when
it comes time to put the unit back together. Lay some clean newspapers on
the bench to protect both the bench and the fixture. The light colour also
helps to contrast small parts which might be dropped during the overhaul
operation, and newspaper makes for a nice work surface.
You should have the following available:
- Screw Drivers
- Nut Drivers
- Rubber Mallet
- Electric Drill or Bench Grinder
- Brass Wire-Brush Drill Attachments (Small and Large)
- Emery Cloth (Grade: Fine)
- Sanding Sponges (Grade: Fine)
- Wool Soap Pads (*Not* Steel Wool!)
- Narrow, Metal Paint Scraper
- Fine-Toothed Flat File
- Scrub Brush
- Tooth Brush
- Dish Detergent
- Electrical Tape (White and Black)
- Permanent Marker (*Not* Water-Based)
- Heat Shrink
- Heat Gun
- Paper Towels
- Spray Paint (Heat Resistant for Metal)
- Alignment Jig and Screen
- Medium Oil
- Silicone Lubricant (Industrial Grade for High Heat Capability)
- AC Volt Meter
- Varsol (Paint Solvent)
- Methanol or Rubbing Alcohol (To be used with caution -- see text)
- Glass Cleaner (To be used with caution -- see text)
- Distilled Water
- Soft, Lint-Free Tissues
- Suitable Selection of Replacement Parts
- Numbered Parts Containers or Muffin Pan
Remember to keep track of the disassembly by making notes, using
numbered containers or a numbered muffin pan to hold the parts removed
during each step, and by making an notes or having an assembled fixture
standing by as a reference. Now do the following:
Working with a room-temperature fixture, first remove any clamp or stand
adaptor, and place it aside. Next, take off the yoke. With some models, the
removal of internal nuts may be required to get the yoke off. Some persons
wait to do the above until after the next two procedures. If you wish to
delay, ensure during movement that the still-attached yoke and clamp do not
damage anything on the bench. It's easy for a less-than-tight yoke to swing
unexpectedly and hit something, or to jam a finger between it and the bench
or the fixture itself.
Now take off the lens tube, if the model does not have an internal
track/holder. It's usually able to be done by unscrewing the lens focusing
knob. Remove the lens(es) either by taking out the retainer ring or by
removing retaining clips. Place the lens(es) in your safe place as
discussed in the Work Area Setup and set aside
the lens tube and any spacers. If the lenses are internal, you will have
to wait to remove them during the body disassembly stage.
Next remove the lamp housing. This is typically done by unscrewing one or
more retainer screws or knobs and removing the assembly. Take out the lamp
and put it in your safe place. Retain the date tag (if there is one) with the
lamp so it can be reattached or recreated upon reassembly. When removing the
lamp, don't be worried about touching the bulb. You will be cleaning it
before re-insertion during the assembly stage at the end. Set the lamp
housing aside. You will not be dissembling this now but will do it during
the electrical overhaul (unless it requires painting. (See that section,
Now, if not already done, detach the yoke and clamp or stand adaptor,
and place them aside.
Return to the fixture body. Remove any brackets or sections by
unscrewing their retainer/adjustment knobs and taking out any screws.
Continue until the remainder of the fixture is apart. Be sure to put the
parts and hardware associated with each disassembly stage into their own
numbered container. You should now have an empty body shell.
INSPECTION and RECONDITIONING
Look at the body to see if there are any dents or bent parts. Repair as
necessary. To pound out dents, use a wooden form and rubber mallet to
lessen metal damage as compared to a direct hammer blow. Inspect the screw
mounts for the yoke; they should not be worn or damaged. If so, then it
means a trip to the machine shop to have it re-threaded. Note that some
models use a "grab plate" locking mechanism, so the yoke mounts are free
to pivot, thus stripped screw mounts are less likely to have happened.
Do the same for the yoke. Note any burrs that should be filed off, and
then straighten the yoke, using a vice if necessary.
Now place the body into a plastic set tub or use rubber mats to protect
an enamel one. Scrub the unit using hot water and dish soap. Use a tooth
brush to get into small areas. Remove rust with a wool-type soapy scouring
pad. Rinse. (A one-metre length of garden hose is good for this.) Dry with
an old towel. Don't use a new one as some rust will likely come off. Hang
the unit up to air dry inaccessible areas. Repeat this procedure for the
For a severely corroded body, and for tarnished hardware, employ a narrow
paint scraper and use a bench grinder with a wire brush to buff the
finish. A brass brush is preferred over steel. If no grinder is available,
use an electric drill with a lockable trigger. Clamp the drill into a vise.
You will likely find that clamping the drill and holding the parts against
the rotating brush works better than clamping the parts. It saves having to
clamp and unclamp each part, and having to put the drill down to do the
re-clamping. Use a pair of pliers, preferably the locking type, to hold
small parts. This will give you more control and also keep your skin away
from the rotating bristles. Work gloves are recommended, as are hearing
protection and goggles or a face shield.
Begin to buff the fixture body. Do not press too hard because the wire
bristles will score the metal. Use the side of the bristles for finer work
with less chance of scoring the metal. You need not take off all the old
paint -- only that which is loose, and of course, surface rust should be
removed, too. Dust the parts off.
(If you are not going to wash what you have buffed, you can skip to
the Painting section so that the first coat on the
fixture body will be drying while you continue with the steps below.)
Take the reflector and place it into the sink. If it's made from
aluminum, use a wool (not steel wool!) soap pad, clean the back of the
reflector as a scratch test. Use the pad with a motion that follows the
reflector shape. If it polishes with no scratches, do the same to the
front. If scratches appear from the test, you will have to decide if it
is better to have a tarnished reflector versus a shiny, scratched one. I
vote for the latter if it reflects more light without too much scatter
rather than leaving it tarnished.
If severely tarnished to the point that it may not be usable, you can
try to polish it with actual steel wool soap pads, or with automotive
rubbing compound. The worst ones will have to be taken to a professional
metal refinisher or be replaced with new ones.
For glass reflectors, handling them by the edges, blow off loose dust
using a can of compressed gas or a squeeze bulb as used by photographers.
Rinse under warm water until no grit is left. To remove film build-up, mix
a small squirt of dish detergent soap and water, and with clean, wet hands
gently wash the reflector. Watch for rough edges that might cause cuts.
Some glass reflectors will have coatings that increase their efficiency.
These can be destroyed if glass cleaner or undiluted alcohol are used on
them. Use only soap and warm water. If the grime is particularly
stuck, a solution of 10% alcohol and water can be employed. Whatever the
material, when finished rinse and air dry. If you find some streaks are
left, you might repeat the process, but used distilled water as a final
rinse. Once completed, place glass reflectors into your safe place with
soft cloths or paper towels protecting them.
Getting back to the fixture, You should have a shutter assembly
that was separated from the housing. If the shutters need replacement
and are the captive type, you will have to drill out the rivets for the
handle or remove its nut & bolt. Now take apart the shutter assembly.
Note the order and orientation of the separator plates and any hardware.
Some ellipsoidals have sprung shutters and it's easy to lose these parts
when taking them apart, so be careful here. Note well the order of these
parts; there can be a lot of them.
Look for worn plates or chafing of the housing. These parts may need to
be replaced. Bent shutters might be able to be straightened, but are
typically unable to be made completely flat. You will have to decide if
they are able to be reused. If they are too kinked, they will bind, and if
corroded to the point of missing sections, replace with new ones. For
reusable ones, buff off all parts with steel wool, or use a sanding sponge
or emery cloth. If small bumps remain, use a flat, fine-toothed file to
remove them while being careful not to file a hole through the plate. It is
imperative that the shutters and any separator plates be as even and as
flat as possible so as to assure bind-free operation and fine adjustment.
The part of the lens tube that slides within the outer housing will need
to be buffed if there is no internal guide track. Use steel wool or a
sanding sponge to attain a smooth surface.
Take the lenses to the sink and place them one at a time on to a cloth
or old towel at the bottom of the sink. Run warm water over them to wash the
loose dirt off and then use dish soap with bare hands to gently clean each
lens. Watch that sharp edges or defects don't cut your hands, and that your
hands don't get so slippery as to make holding on to the lens difficult.
Plano lenses are expensive, so you won't want to break them.
As with glass reflectors, use only a solution of soap and water and
clean hands. Step lenses often have black risers. Be careful not to
remove this paint. Some lenses will have coatings that increase their
transmission of light. These can be destroyed if glass cleaner or
undiluted alcohol are used on them. Even though some can handle alcohol,
as a caution use only soap and warm water even if the manufacturer
states otherwise. It's possible that someone could have replaced a lens
with one which coating cannot handle even alcohol. If you suspect this,
follow the reflector cleaning instructions father back. Whatever the
material, when finished cleaning, rinse and air dry. Place the lenses back
into your safe place with cloths or paper towels protecting them.
Clean and recondition any remaining items. Pipe clamps and stand adaptors,
along with their hardware, typically require wire brushing and repainting.
Take the clamp apart to do this. Set aside the parts to be repainted. Review
the electrical section if the lamphouse requires re-painting. Replace any
severely rusted parts if they can't be buffed cleanly by the wire brush.
Coat unpainted, cleaned hardware with a medium machine oil.
Move to the socket assembly. Remove the socket and inspect the contact
screws. Burnish off any corrosion there and inside the socket. If it
remains severely discoloured, you should replace it. (Discoloured sockets
can contribute to reduced lamp life.) When doing so, be sure to replace the
insulator wafer under the socket if it's damaged, split, or missing. (Some
ellipsoidal sockets do not use such an insulator.)
If the line cord is attached through a strain relief, remove both and
inspect. Should the cord be melted, frayed, or brittle, it will require
replacement. If it's old and uses asbestos wiring, install a new line
cord. Asbestos conducts electricity when wet and is hazardous to breathe.
Put the wiring into a plastic grocery bag and send to recycle or to your
local Hazardous Waste Facility.
Some line cords may use fibreglass sheaths. Replace or repair as
necessary. If cord damage is external to the fixture body, you may use
electrical tape or heat shrink after the repair. If it's internal, cut
off the bad part of the sheath and slide a good section inside. Make up
the shortfall on the other end with an appropriate length of sheathing
coupled via heat shrink or black electrical tape. When the light is fully
assembled, the sheath should run from the socket assembly, along the
line cord and into the plug at the other end.
Clean off the socket mount and inspect for damage. Repair as necessary.
If it's rusted, it will have to be scraped or buffed, washed, and then
painted with a heat-resistant finish. If painting is required, follow the
If it is determined that some parts need to be repainted, and the dent
repair and rust removal has been completed, it's time to paint. Confirm
that the fixture or parts are clean and dry, and then proceed to your
Mask any things to not be painted such as electrical stickers, screw
threads, or lens barrels that must slide without guide tracks. To facilitate
tape removal, leave a tab on the tape by folding a small bit of the sticky
side back on to itself.
Get out your spray paint. I suggest a heat-resistant flat black for the
inside and a satin black for the exterior. Some prefer flat black for all.
I like to have the lens tube and gel frame holder be flat -- inside and out,
save for any part that slides. Alternatively, you may wish to use a
company/individual colour for the outside.
Shake the can well, and in a well-lit area, spray in even strokes,
releasing the nozzle at each end of the pass. Repeat for the yoke, hanging
each to dry in a non-dusty area. Keep the coats thin and allow to dry
between coats as per instructions on the can. Use paint solvent to clean
overspray. Allow to dry. Realise that dry paint can still be soft
underneath, so handle carefully. It is best to wait over night so as to
achieve a fully cured, hard coating.
If the exterior is to be a different colour, after the interior has
dried, coat it using the technique above. Keep overspray out of the
interior. You may have to touch up the inside after the exterior has
been completed. Allow to dry. After each painting session, blow out the
paint can nozzle by turning it upside down and spraying until only
propellant comes out. To lessen waste, I always do this onto one
of the lights I am in the process of painting.
REASSEMBLY and LUBRICATION
You should now have a number of sections and parts which are clean,
non-damaged and possibly repainted. Being careful of your new paint work,
start to reassemble the fixture in reverse order, beginning with any
internal sections. Pay particular attention to the shutter assembly which
must be put together in the right sequence and orientation. As mentioned,
paint may take a day or so to harden completely, hence the caution if
handling too soon.
Lubricate any hardware with a long-lasting, medium oil, and use silicone
spray for any lens guides or parts that slide past one another. Keep oil
and silicone off any parts not intended. This is especially true for the
lenses, reflector, and lamp. Keep these different lubricant types apart
from one another, too. In addition, keep them off your bench. An
oil/silicone soaked bench is not a good environment for lighting fixtures
because it will work its way into areas where it is not wanted. Replace
bench-top newspapers often.
Put the electrical back together. Use silicone spray in the socket. This
will facilitate later lamp removal in that it will help prevent lamp/socket
freeze up. Don't worry about exact socket placement, but try to get it close
to where it was before disassembly. The lamp will be aligned in the next
section. Replace the lamp and wipe the bulb with soft tissue dipped in
methanol or rubbing alcohol to remove dirt and finger oils. Restore the
lamphouse to the fixture.
Make a new date tag by using white electrical tape placed on the inside
of the yoke. If the original installation date is unknown, write the current
year (four digits) and month (three letters) and `P.I.S.' The latter stands
for "Previously in Service". If a new lamp is installed, only the year and
month are required. This is done so you will know the kind of lamp life a
given fixture and lamp type provides. Make the date tag be twice the required
length so that at the next lamp replacement, there will be room to write the
new date. This way, the date tag only need be replaced every second burnout.
For the lenses, gently use a soft cloth to remove any handling finger
prints or smudges that happened after the washing process, or repate the
cleaning process and use distilled water as a final rinse. Remember to
keep glass cleaner and alcohol away unless you are absolutely sure the
lenses have no optically-enhancing coating. Restore the lenses to the tube
or internal track/holder using any required separator elements. Note that
in some models, the separators must be oriented to allow the operation of
focusing devices or retainer knobs.
Confirm that the lenses are loose! Do not place retainer clips or rings
hard against them. They must have room to expand during operation. Place
the lens tube into the fixture. You may wish to silicone this tube, but
skip it if the extended tube will get touched and transfer silicone to a
person's hands. This can cause problems due to its extreme slipperiness.
Do the final assembly using the remaining parts, but you may elect to
leave the yoke and pipe clamp off until after the alignment is done.
This requires a stand or jig which will support the ellipsoidal with
its shutters open. It may be made of wood or metal but should have the
cradle lined with cloth, rubber, or carpet to prevent scratching the
fixture body. Alternatively, one can use a pipe on to which to clamp the
light. Also, a screen or flat white wall is required for proper alignment.
A bonus is if the screen or wall can have a center dot and concentric
circles at half-metre intervals.
Begin by setting the light in the cradle so that it is level and the
center of the lens aligns to the screen's center point. Plug the fixture
into a dimmer and reduce light output to the lowest setting that still
produces a bright circle. This is to lessen the chance of lamp burnout
during possible rough movement.
Moving the lenses, make the image edge sharp. For variable focus (zoom)
fixtures, set the image diameter to a middle size, or if the location and
use are known, to a size that suits. This will matter less with top quality
units as they exhibit the same characteristics regardless of zoom setting.
However, some cheaper units may vary, hence this suggestion.
Exact alignment procedures cannot be given because they differ from
manufacturer to manufacturer and sometimes from model to model. However,
via either set screws or a single-control alignment adjuster, move the
lamp in and out of the reflector to achieve the brightest circle on the
screen. You may do a preliminary test on some models by not securing the
lamp and electrical assembly in its housing and carefully moving it by
hand in and out of the lamphouse while tilting it back & forth and
up & down. When you see the desired brightness and degree of evenness
on your alignment surface, note the position and angle of the assembly in
your hand. This will give you a rough idea of where the alignment mechanism
must be set.
The hand method is not likely to be needed in modern fixtures, but
for older ones, especially those with the three-screw alignment setups,
it can speed the procedure. Reseat the assembly and adjust it to that
point; test by moving it around by hand until it's the way you want,
and continue adjustments. Secure the assembly in the lamphouse.
Now do a fine adjustment to achieve a flat or peak field, and if peak
field is chosen, where that peak occurs. This means the fixture will either
produce an even illumination within its circle of light (flat), or it will
have a hot spot somewhere (peak). An off-center peak spot is achieved by
sideways or up & down movement of the alignment adjusters. You will
see a brighter area move around within the circle.
For theater stage washes, this hot spot occurs in the center. For key
light purposes, it often is near the top of the beam to throw more light on
a person's head area or face. If unsure, go with a flat field. Check your
alignment again with the dimmer at the full-rated voltage of the fixture's
lamp. Although not necessary, one can use a volt meter to ensure this
voltage is correct. Re-adjust alignment as necessary.
You should now have a
ready for new service.