Replacing Lamp & Ballast in Optoma HD72 Projector
By Mark R. Spiering
13Feb10
The Optoma HD72 DLP
projector was an instant success when released in February of 2006. Garnering much praise from consumer
electronics pundits as well as popularity among home enthusiasts, the HD72
offered an impressive array of features at a remarkable price point. It was one of the first 720p projectors at an
affordable, entry-level position, aimed squarely at the first-time buyer.
However, the projector does
have an Achilles heel. As the lamp ages
with use, increasing levels of stress are placed on the ballast (lamp driver)
every time the projector is turned on.
Over time, a fault* develops in the ballast where it cannot properly
hold the current once the mercury vapor in the lamp has ignited after a
high-voltage strike. This results in the
lamp suddenly extinguishing after a minute or two while the projector continues
to run. No lamp or temp LEDs will be
illuminated. Pressing the power button
twice will initiate the shut-down sequence as normal.
This do-it-yourself guide
will provide step-by-step instructions to replace both the lamp and the ballast
together. The first part focuses on the
ballast while the second part deals with the lamp.
Before
beginning with these instructions, install the lens cover.
First, carefully turn the
projector over as shown in figure 1 below.
A helpful hint is to use a towel or cloth to protect the top of the
housing.
Figure 1 Bottom of Projector
Next, remove the panel to
expose the lamp carrier assembly as shown in figure 2 on the following page.
Figure 2 Lamp Carrier Assembly
Loosen the two screws
securing the assembly in the projector.
The screws are captive in the assembly and will not be able to be
removed.
Swing the metal loop upwards
and gently pull the assembly out of the projector. The lamp connectors are friction fit and will
separate with enough applied force.
Do not touch
the glass of the lamp with bare fingers.
Set the lamp assembly aside.
Next, loosen the five (5)
screws that secure the top of the housing.
They are in deep wells in the bottom of the housing so extracting them
might not be possible.
Carefully turn the projector
right side up. The screws should drop
out of the wells.
Starting with the front
(lens side) of the projector, carefully lift the top (white) part of the
housing. It should lift up at least a
half inch before resistance from the back can be felt. There are four (4) clips holding the top to
the bottom of the housing at the rear.
With gentle but firm force, they will release, allowing the top to be
lifted a few inches but not completely off.
There are two connections
for the top controls that plug into the main board as shown in figure 3 on the
following page.
Figure 3 Top Control Connections
Carefully disconnect the two
cables from the main board connectors.
Remove the top of the housing and set it aside, exposing the inner
components as shown in figure 4 below.
Figure 4 Projector Inner Components
Next, carefully lift the
black shield over the main board connectors near the front edge. The shield is held down by an adhesive; it
will come loose with gentle but firm force.
Do not attempt to remove the shield. Make note of the cables and their respective
connectors on the main board as shown in figure 5 below.
Figure 5 Main Board Connectors
Carefully disconnect each of
the cables going to the main board.
There is also a power connection to the main board as shown in figure 6
on the following page. Carefully
disconnect the power cable.
Figure 6 Main Board Power Connector
Next, remove the five (5)
screws that secure the main board in the chassis. Carefully lift up on the board to disconnect
the edge connector to the DLP assembly on the other side. Once the main board is loose, remove it from
the chassis as shown in figure 7 below.
Figure 7 Main Board Removed
Set the main board
aside. It is sensitive to static
electricity discharge so place it on a sheet of aluminum foil if an anti-static
bag is not available as shown in figure 8 below.
Figure 8 Main Board on Aluminum Foil
With the main board removed,
the ballast is exposed as shown in figure 9 below.
Figure 9 Ballast Exposed
Next, carefully disconnect
the three (3) cables connected to the ballast.
Loosen the three (3) screws securing the ballast to the chassis. Remove the ballast as shown in figure 10
below.
Figure 10 Ballast Removed
The new ballast is shown in
figure 11 below.
Figure 11 New Ballast
Next, install the new
ballast and secure it with the screws.
Reconnect the cables to the ballast as shown in figure 12 below.
Figure 12 New Ballast Installed
Next, carefully align the
main board edge connector with the DLP assembly PCB. Press down to reconnect the main board while
ensuring the mounting holes line up with the screw PEMs in the chassis. Secure the main board screws as shown in
figure 13 below.
Figure 13 Main Board Installed
Next, reconnect all the
cables to the main board as shown in figure 14 below.
Figure 14 Main Board Connections
Next, position the top of
the housing so that the two top control connections can be made to the main
board. Carefully reconnect the cables
(as shown in figure 3 earlier).
Align the top of the housing
and move it into position over the bottom part.
Snap the back of the top down with gentle but firm force. The front should have very little split in
the housing.
Carefully turn the projector
over. Drop the five (5) screws into the
wells and tighten. Do not over
tighten the screws.
Set the projector aside.
Handle the lamp carrier
assembly by the frame only as shown in figure 15 on the following page.
Do not touch
the glass of the lamp with bare fingers.
Figure 15 Handling Lamp Assembly
Next, carefully peel back
the rubber boots on the connections to the lamp. Disconnect the two power leads as shown in
figure 16 below.
Figure 16 Power Leads Disconnected
Next, remove the screw and
metal clip in the lower right-hand corner of the frame as shown in figure 17
below.
Figure 17 Screw and Clip Removed
Loosen but do not remove the
two mounting screws on the left-hand side of the frame. The lamp should be loose enough to be
removed.
Handle the lamp
only by the ceramic base. Do not touch
the glass.
Remove the lamp from the
carrier assembly as shown in figure 18 on the following page.
Figure 18 Lamp Removed
Carefully remove the new
lamp from the packaging as shown in figure 19 below. Do not bend or distort the exposed lead
wire.
Figure 19 New Lamp Packaging
Next, carefully install the
lamp into the carrier assembly.
Reinstall the lower right-hand mounting screw and clip. Tighten but not all the way; leave a little
loose. Tighten the two left-hand
mounting screws. Finally, tighten the
right-hand screw. Do not over tighten
the screws.
Next, reconnect the two
power leads. Slip the rubber boots into
position. Do
not touch the glass.
Next, reinstall the lamp
assembly into the projector (as shown in figure 2 earlier). Tighten the two screws to secure the
assembly. Do not over tighten the
screws.
Finally, reinstall the lamp
cover. Carefully turn the projector
over.
Connect a power cord to the
project and turn it on. Run the
projector for at least 15 minutes to verify the lamp remains ignited as shown
in figure 20 below.
Figure 20 Testing the Projector
This concludes these
instructions.
* (from page 1) The exact failure mode of the ballast is unknown at this time. Investigation into the exact root cause will be conducted in the future using worn lamps and ballast samples as well as fresh ones. By studying the contrasting performance between the two sets, it is hoped a simpler remedy than replacing the entire ballast can be found.
Parts Suppliers
Ballast (Lamp Driver
Assembly)
Part Number 75.83J01G002
Budgetary Price 99.00 USD
Optoma Customer Service
(408) 383-3700 main number
(888) 942-2929
out-of-warranty service
Mercury-Vapor Arc-Flash
Lamp
Part Number Osram P-VIP
180-230/1.0
Budgetary Price 130.00 USD
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