LEAKAGE CURRENT COLD CHECK
1. Unplug the ac line cord
and connect a jumper between the two prongs of the plug.
2. Turn on the power switch.
3. Measure the resistance value between the jumpered ac plug and all exposed
cabinet parts of the receiver, such as screw heads, antennas, and control
shafts. When the exposed metallic part has a return path to the chassis, the
reading should be between 1 megohm and 5.2 megohms. When the exposed metal does
not have a return path to the chassis, the reading must be infinity. Remove the
jumper from the ac line cord.
LEAKAGE CURRENT HOT CHECK
1. Do not use an isolation transformer for
this test. Plug the completely reassembled receiver directly into the ac
outlet.
2. Connect a 1.5k, 10W resistor paralleled by
a 0.15uF. capacitor between each exposed metallic cabinet part and a good earth
ground such as a water pipe, as shown below.
3. Use an ac voltmeter with at least 5000
ohms/volt sensitivity to measure the potential across the resistor.
4. The potential at any point should not
exceed 0.75 volts. A leakage current tester may be used to make this test;
leakage current must not exceed 0.5mA. If a measurement is outside of the
specified limits, there is a possibility of shock hazard. The receiver should
be repaired and rechecked before returning it to the customer.
5. Repeat the above procedure with the ac
plug reversed. (Note: An ac adapter is necessary when a polarized plug is used.
Do not defeat the polarizing feature of the plug.)
OR
With
the instrument completely reassembled, plug the ac line cord directly into a
120Vac outlet. (Do not use an isolation transformer during this test.) Use a
leakage current tester or a metering system that complies with American
National Standards Institute (ANSI) C101.1 Leakage Current for Appliances and Underwriters
Laboratories (UL) 1410, (50.7). With the instrument ac switch first in the on
position and then in the off position, measure from a known earth ground (metal
water pipe, conduit, etc.) to all exposed metal parts of the instrument
(antennas, handle brackets, metal cabinet, screw heads, metallic overlays, control
shafts, etc.), especially any exposed metal parts that offer an electrical
return path to the chassis. Any current
measured must not exceed 0.5mA. Reverse the instrument power cord plug in the
outlet and repeat the test. See the graphic below.
PRACTICAL SERVICE
PRECAUTIONS
IT MAKES SENSE TO AVOID EXPOSURE TO ELECTRICAL SHOCK. While some
sources are expected to have a possible dangerous impact, others of quite high
potential are of limited current and are sometimes held in less regard.
ALWAYS RESPECT VOLTAGES. While some may not be dangerous in themselves,
they can cause unexpected reactions – reactions that are best avoided. Before
reaching into the powered color TV set, it is best to test the high voltage
insulation. It is easy to do, and is just a good service precaution.
BEFORE POWERING UP THE TV WITH THE BACK OFF (or on a test fixture),
attach a clip lead to the CRT DAG ground and to a screwdriver blade that has a
well insulated handle. After the TV is powered on and high voltage has
developed, probe the anode lead with the blade, starting at the bottom of the
High Voltage Transformer (flyback – IFT). Move the blade to within two inches
of the connector of the CRT. IF THERE IS AN ARC, YOU FOUND IT THE EASY WAY,
WITHOUT GETTING A SHOCK. If there is
an arc to the screwdriver blade, replace the High Voltage Transformer or the
lead, (if removable) whichever is causing the problem.
PICTURE TUBE REPLACEMENT PROCEDURE
Note: a. Two (2) people are required to
handle this picture tube.
b. Safety Glasses must be worn during this
procedure or whenever directly handling a picture tube.
c. Take care in each step not to damage the
CRT or the cabinet.
1. Remove the Chassis and the CRT Socket
Board Module from the cabinet.
2. A furniture pad or blanket should be
positioned on the floor to support only the CRT Face. This pad or blanket
should be high enough to keep the CRT Face approximately 12 to 14 inches off
the floor.
3. Using two people, place the cabinet in a
front down position with the CRT Face on the pad or blanket.
4. Place padded blocks under each corner of
the cabinet to keep it from rocking.
5. Remove the four screws, at the corners of
the CRT.
6. With two people lowering the cabinet to
the floor, leave the CRT elevated by the pad or blanket. Note: Take care not to grasp the neck of the
CRT during this procedure, as it is extremely fragile.
7. Two (2) people may then lift the CRT from
the cabinet.
8. Remove the degaussing coil from the
defective CRT and mount on the replacement. Take care to maintain the exact
shape and fit
MODEL TO CHASSIS LIST
MODEL TO PANEL LIST
For the most current Mode to Panel list, type “CBA” while viewing the exploded
view or schematic. If a list of all modules/panels for all models is desired,
click “CBA/Acc. Parts” while viewing the parts list. A list of these parts can then
be printed.
Remote Cross Reference
For the most current list of remote control part numbers, type “remote” while
viewing the exploded view or schematic. If a list of all remotes for all models
is desired, click “CBA/Acc. Parts” while viewing the parts list.
A list of these parts can then be printed.
FULL SCHEMATIC [CIRCUIT DIAGRAM] and waveforms
QUESTIONS / ANSWER FOR PHILIPS PTV835, PTV836, PTV840, PTV881, PTV842, PTV843, PTV853, PTV854 AND PTV855
I have a philips HD rear projection TV 60 in. inside there are six adjustment knobs. Three are color the other three are for brightness contrast and hue. Which is which Left to right ?
If yours is a rear projection TV the adjustment knobs on the focus block inside are screen (red, green, blue) and focus (red, green, blue). The ones you are referring to as color are the screen controls and they adjust the intensity of the color from each tube. The other set adjust the focus of each color. They are also not intended to be adjusted by the user. Unless major components have been changed these controls should not need adjustment. That is why they are inside the TV.
We have a 60 inch philips tv that started to have problem with overexposed color (blue) i thought that i could fix this, i moved the lenses a bit rendomly,that did help a little, but then i touched the...
Thats the screen controls. To adjust it turn the color level down to zero, Then adjust the 3 knobs by balancing them to where the best black and white picture is acheived. Then turn the color level up and that should do it. Just be careful not to turn the settings too low or the CRTs will refuse to light after the set gets turned off. If that happens you will need to turn each adjustment up a little and the CRTs will relight then you will need to adjust it more. If you cannt get a good black and white picture you will need to replace the Coolant in the CRts.
Why cant i manually adjust the color convergence ?
The thought is that the Amplifier that controls this color has gone bad. If you tweaking the Global L&R Horizontal knob and nothing is happening. Then the amp is shot.
May have to replace the Amp or the whole board.
If you are not able to adjust the convergence using the remote you will need to replace the convergence chips.
Typical Symptoms
1) Convergence menu does not work for one or more colors.
Such as: Red moves up,down, but left or right fails.
2) Screen is bowed looking.
If you have one or more of the problems above you need to replace the convergence chips.
The easiest way to balance the gray scale is to turn the color all the way down on the set. The next part is easier with two people if the screen controls are on the back of the set. This is the part you saw that has six small knobs on it. There are control for the focus of the red, gree and blue and for the screen level of the red, green and blue. You will want to adjust the screen controls in an effort to get the picture black and white (this is why you turn the color down), hence the term "gray scale". Just make slight adjustments, take your and be patient. It will take some time, but you will get your picture balanced back out in time.
CONVERGENCE SERVICE MODE PROCEDURES
Note: This procedure is required for all of the following geometry and
convergence adjustments.
Using the remote transmitter, enter the following seven-button sequence to
activate the convergence mode.
06 - 25 - 97 - Menu (M)
The "Opening Menu" will appear offering choices:
Channel 3
Use Channel up/down to
Select a Channel with Video
Remote control key functions:
Use arrow up/down and left/right: Adjust Convergence
M: Advance "cross" location
Up, Down, Left, Right
3: Exit Convergence
Status: Abort/Cancel Changes
M: Begin Convergence
Note: video information must be present to correctly adjust the
convergence. A signal source is required to lock the vertical and
horizontal sync. After entering the "convergence service mode" verify the
presence of a video source by confirming the presence of active audio (use
the volume up function on the remote). Use the channel up and down function
on the remote to select the desired tuning source.
Select item "M" from the first menu, the "Convergence Menu" will appear
featuring 5 possible selections.
Channel 3
Convergence:
1. green geometry
2. red To green Convergence
3. blue To green Convergence
4. green To red Convergence
5. green To blue Convergence
Status: Abort/Cancel Changes
CONVERGENCE TOUCH UP PROCEDURE
1. Enter the "convergence service mode" as described above in the
"convergence service mode procedure".
2. Select the desired color requiring adjustment. Note: Do not
select Green Geometry (1). This procedure is described under "Major
Convergence/Geometry Alignment. If Green Geometry is altered during this
procedure a "Major Convergence/Geometry Alignment" maybe required.
3. Cover the Output Lens of the single color presently NOT being
adjusted. Example: If you select Green to Red Convergence (4) cover the Blue
Output Lens.
4. The highlighted adjustment Icon (Cross) should be illuminated on
the middle left side of the screen. Make the necessary Convergence
Adjustments using the following Remote Keys:
· Use the Arrow Up ( ) to adjust the selected color up.
· Use the Arrow Down Key ( ) to adjust the selected color down.
· Use the Arrow Right Key (-) to adjust the selected color to the
right.
· Use the Arrow Left Key (+) to adjust the selected color to the
left.
5. Move to the next location to be converged. It is not required
that the full Convergence Sequence be followed while performing the
"Convergence Touch Up Alignment Procedure". The following alternate Remote
Keys allow for positioning of the Icon to the desired adjustment location:
· Key 2 on the Remote Transmitter will position the Adjustment
Icon upward on the screen.
· Key 8 on the Remote Transmitter will position the Adjustment
Icon downward on the screen.
· Key 4 on the Remote Transmitter will move the Adjustment Icon
to the Left.
· Key 6 on the Remote Transmitter will move the Adjustment Icon
to the Right.
6. Return to the "Convergence Service Menu" by selecting Key number
3 on the remote transmitter or by sequencing the Icon to the last adjustment
point at the lower right corner of the screen and pushing the Menu (M) Key
on the Remote Transmitter..
7. Repeat steps 1 through 6 for other required Convergence
Alignments.
8. To Save the Adjustment completed in the last procedure,
Exit/Save the Convergence Service Mode by selecting Key 1 on the Remote
Transmitter. This forces the corrections to be written to the EEPROM on the
Convergence Module.
