REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

How to use the site:

- If you landed here via any Search Engine, you will get what you searched for and you can search more using the search this blog feature provided by Google. You can visit more posts scrolling the left blog archive of all posts of the month/year,
or you can click on the main photo-page to start from the main page. Doing so it starts from the most recent post to the older post simple clicking on the Older Post button on the bottom of each page after reading , post after post.

You can even visit all posts, time to time, when reaching the bottom end of each page and click on the Older Post button.

- If you arrived here at the main page via bookmark you can visit all the site scrolling the left blog archive of all posts of the month/year pointing were you want , or more simple You can even visit all blog posts, from newer to older, clicking at the end of each bottom page on the Older Post button.
So you can see all the blog/site content surfing all pages in it.

- The search this blog feature provided by Google is a real search engine. If you're pointing particular things it will search IT for you; or you can place a brand name in the search query at your choice and visit all results page by page. It's useful since the content of the site is very large.

Note that if you don't find what you searched for, try it after a period of time; the site is a never ending job !

..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Wednesday 13 March 2019

PHILIPS 55P9271 SERVICE MODE

PHILIPS 55P9271 SERVICE MODE

         


  SERVICE MODE


Service Mode Entry and Exit

Using the remote control transmitter, enter the following seven-button sequence to activate the service mode:
1. Digit 0
2. Digit 6
3. Digit 2
4. Digit 5
5. Digit 9
6. Digit 6
7. Menu

Depressing the power button on the front of the PTV will exit the service mode, save the current modification, and turn the set off. Important There are 95 registers within this system. Some of data held in these registers should not be altered and some of the other registers are factory set and unique to the unit under test. This procedure could save a significant amount of time should a mistake occur which causes an undesirable condition to the unit under test.

Description of Service Mode

The service mode is used for changing service control register values from their default values to new values; this includes all factory-preset conditions.
When entering the service mode, the tuning system will attempt to retrieve the current register values stored in the EEPROM (7304). If the EEPROM has never been programmed, default data values will be stored.
Pressing the power button on the front of the PTV while in this service mode, or setting the value of Register 00 to "00" will cause the tuning system to write all modified values to the EEPROM IC before chassis power is turned off.


SERVICE ADJUSTMENTS
PTV 830-865 Chassis GR9D Chassis
The Large Signal Panel incorporates a "hot" ground system. Always use a separate isolation transformer
when applying power to the exposed chassis.
Service Adjustment Notes

Unless otherwise specified:
1. All service adjustments are "hot" voltagewise. For maximum safety, ensure the use of properly insulated tools.
2. Many of the following adjustments are made through software intervention. The user remote control transmitter is required in order to modify register values stored within the EEPROM IC on the Main Chassis Board Assembly.
3. Grid locations (e.g., D-2) next to control reference numbers refer to PC board zone locations.

On-screen Oscillator Setup

1. Turn the set on and tune to a broadcast television signal.
2. Connect a digital voltmeter to F041 (Positive side of capacitor 2387) on the Small Signal Panel.
3. Adjust 2341 (zone E-6) to obtain a reading of 2.5Vdc (0.1V) on the meter.
Note: This adjustment may affect onscreen menu positioning or other graphics generated by the set. Refer to ”Modifying Factory Default Values“ and the contents of DAC registers 22 and 23 for vertical and horizontal positioning of the onscreen display (OSD).

RF AGC Delay (Small Signal Panels ASG059, ASG060, ASG061, ASG062, ASG063)

Tuner 1
Note: This control (3202) is located on the Small Signal Panel in zone area J-2.
1. Tune to a weak station, or loosely couple the antenna to observe a snowy picture.
2. Set the RF AGC Delay Control (3202) to its fully counterclockwise (CCW) position.
3. Slowly advance 3202 clockwise (CW) to a point slightly beyond the point of minimum snow.
Note: Do not advance the control beyond this point, as it may result in an overloaded picture on the face of the CRTs (caused by a strong signal from local station). The range of the AGC voltage supplied to pin 1 of 1900 (see F003) of the Varactor Tuner will vary from approximately 4.2Vdc (without signal) to about 1.87Vdc (RF signal of 10mV).

Tuner 2
Note: This control (3256) is located on the Small Signal Panel in zone area K-5.
1. Tune to a weak station, or loosely couple the antenna to observe a snowy picture.
2. Set the RF AGC Delay Control (3256) to its fully counterclockwise (CCW) position.
3. Slowly advance 3256 clockwise (CW) to a point slightly beyond the point of minimum snow.
Note: Do not advance the control beyond this point, as it may result in an overloaded picture on the face of the CRTs (caused by a strong signal from local station). The range of the AGC voltage supplied to pin 1 of 1900 (see F005) of the Varactor Tuner will vary from approximately 4.2Vdc (without signal) to about 1.87Vdc (RF signal of 10mV)

VCO and AFT Adjustment (Small Signal Panels ASG059, ASG060, ASG061, ASG062, ASG063)

Tuner 1

1. Cut the shield breakpoints around 7200 and the IF circuitry (see zone K-2). Remove the top cover of the shield to gain access to the internal circuitry.
2. Short circuit test points F016 and F017 (pins 1 and 2 of 7200).
3. Short circuit test point F023 (pin 13 of 7200) to ground (the shield around 7200 is a convenient ground).
4. Connect a DC voltmeter to test point F007 (pin 18 of 7200).
5. Turn the set on and record the voltage reading from test point F007 (typically 4.5 to 5.0Vdc).
6. Turn the set off and remove the short circuits from test points F016, F017, and F023.
7. Connect coincidence line test point F047 (at resistor 3361, near pin 45 of 7300) to the +5Vdc line on 1900.
8. Turn the set on and tune to a local broadcast signal.
9. Select Cable Tuning from the menu system. Select channel 36 or another high band inactive cable channel.
10. While still in the cable mode, select a local VHF broadcast channel. The tuning system will attempt to tune three times, then lock on to the FCC-assigned frequency.
11. Adjust the AFT Coil (5202) to obtain a reading of 7.1Vdc (25mVdc) at test point F004.
12. Adjust the VCO Coil (5204) to obtain the same DC voltage reading at test point F007 that was noted in step 5 of this procedure.
13. Remove the jumper from the coincidence line (F047).
14. Verify this adjustment by changing between the high band inactive cable channel and a local VHF broadcast channel (ensure that the local broadcast channel locks in quickly).

Tuner 2

1. Cut the shield breakpoints around 7201 and the IF circuitry (see zone K-5). Remove the top cover of the shield to gain access to the internal circuitry.
2. Short circuit test points F009 and F010 (pins 1 and 2 of 1204).
3. Short circuit test point F025 (pin 13 of 7201) to ground (the shield around 7201 is a convenient ground).
4. Connect a DC voltmeter to test point F008 (pin 18 of 7201).
5. Turn the set on and record the voltage reading from test point F008 (typically 4.5 to 5.0Vdc).
6. Turn the set off and remove the short circuits from test points F009, F010, and F025.
7. Connect coincidence line test point F047 (at resistor 3361, near pin 45 of 7300) to the +5Vdc line on 1901.
8. Turn the set on and tune to a local broadcast signal.
9. Select Cable Tuning from the menu system. Select channel 36 or another high band inactive cable channel.
10. While still in the cable mode, select a local VHF broadcast channel. The tuning system will attempt to tune three times, then lock on to the FCC-assigned frequency.
11. Adjust the AFT Coil (5219) to obtain a reading of 6.6Vdc ( 25mVdc) at test point F002.
12. Adjust the VCO Coil (5220) to obtain the same DC voltage reading at test point F008 that was noted in step 5 of this procedure.
13. Remove the jumper from the coincidence line (F047).
14. Verify this adjustment by changing between the high band inactive cable channel and a local VHF broadcast channel (ensure that the local broadcast channel locks in quickly).

Sound Alignment (Small Signal Panels ASG059, ASG060, ASG061, ASG062, ASG063)

Tuner 1
Note: This control (5201) is located on the Small Signal Panel in zone area J-2.
1. Select an active channel and loosely couple the antenna until noise/distortion is apparent in the output.
2. While keeping input signal weak enough to produce noise, adjust the Sound Discriminator (5201) for maximum output and minimum distortion.

Tuner 2
Note: This control (5218) is located on the Small Signal Panel in zone area K-6.
1. Select an active channel and loosely couple the antenna until noise/distortion is apparent in the output.
2. While keeping input signal weak enough to produce noise, adjust the Sound Discriminator (5218) for maximum output and minimum distortion.
130Vdc B+ Adjustment
Note: This control (7402) is located on the Large Signal Panel.
Upon replacement of the Large Signal Panel, or if a problem with the 130Vdc source is suspected, check and adjust in the following manner.
1. Connect the positive lead from a 0.1% digital voltmeter to the 130Vdc source F004 (Resistor 3453).
2. Connect the negative lead to the isolated "cold" ground.
3. Adjust 3455 (also located in the top corner of the board) to obtain a reading of 130Vdc ± 0.5Vdc.

High Voltage Adjustment

EXERCISE EXTREME CAUTION WHEN ADJUSTING HIGH VOLTAGE.
Note: The following test equipment must be used.
· High voltage probe
· Digital multimeter with 1% (or better) dc accuracy and an input impedance of 10 Megohms ± 10%

Initial settings:
· Turn the PTV on.
· Confirm that the 130V source (F004) is 130V ± 1.0V.
· Perform the 130Vdc B+ adjustment if the voltage is not within specified limits.
· Select a non-used AUX input for a black picture.
· Turn the PTV off.
With the PTV off and unplugged, connect a Fluke Model 80K-40 (or equivalent) high voltage probe as follows and adjust the high voltage.
1. Connect the ground lead to the chassis ground.
2. Connect the high voltage probe to the digital multimeter.
3. Set the digital multimeter to measure dc volts.
4. Remove one of the CRT anode connections from the high voltage splitter.
Note: Make sure that 3943 is turned fully clockwise.
5. Insert the probe tip into the open CRT anode connection of the high voltage splitter
6. Turn the set on.
7. Adjust 3943, High Voltage Adjust, on the Large Signal Panel (zone H-2) for a reading of 30kV ± 200V.
8. Turn the set off.
9. Remove the high voltage probe.
10. Reinstall the CRT anode connector.
11. Turn the set on and confirm proper operation.

High Voltage Frequency Adjustment
Note: This control (3901) is located on the Large Signal Panel in zone area H-3.
1. Turn the set off and disconnect the ac input power.
2. Disable the high voltage by shorting the collector of 7902 to ground.
3. Disable the sync input to 7950 by shorting the base of 7900 to ground.
4. Connect a frequency counter to pin 1 of 7950.
5. Turn the set on and adjust 3901 to obtain a reading of 15.75kHz on the frequency counter.
6. Turn the set off and remove the short circuits and the frequency counter.
Note: Some frequency counters may be too sensitive at one attenuation level and not sensitive enough at
another. In this case, an oscilloscope may be used. Adjust 3901 to obtain a 63.5S delay from the
leading edge of the first main pulse to the leading edge of the second main pulse.

Video Level Alignment (Small Signal Panels ASG059, ASG060, ASG061, ASG062, ASG063)

Tuner 1
Note: This control (3244) is located on the Small Signal Panel in zone area K-3.
1. Apply an NTSC color bar pattern signal to the antenna terminals.
2. Tune to the signal applied in step one.
3. Connect an oscilloscope to the emitter of 7207 (test point F001) and adjust the Video Level Control (3244)
so that the video signal observed on the oscilloscope is 2Vp-p ± 50mV.

Tuner 2
Note: This control (3265) is located on the Small Signal Panel in zone area K-5.
1. Apply an NTSC color bar pattern signal to the antenna terminals.
2. Tune to the signal applied in step one.
3. Connect an oscilloscope to the emitter of 7007 (test point F006) and adjust the Video Level Control (3265)
so that the video signal observed on the oscilloscope is 2Vp-p ± 50mV.

PROGRAMMING FACTORY DEFAULT VALUES

The chassis is controlled by an onboard microcomputer and peripheral parts which make up the tuning system. The customer picture and sound adjustments are made using either the on-set keyboard or the remote control transmitter to enter commands. There are onscreen graphics to show the menu list of adjustments. Service mode makes it possible to change the values of special memory registers in the EEPROM (7304). These registers control the customer adjustments, PIP setups, graphics intensity, and clock calibration. These
registers also make possible many other service adjustments which previously would have been controlled by conventional components mounted on the PC board.