REPAIRING AND NOT THROWING AWAY

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.

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..............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!

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All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Wednesday 27 March 2019

LG PJ350 PLASMA _ Z-SUSTAIN BOARD _ Z-BIAS ADJUSTMENT & DISASSEMBLY OF CIRCUIT BOARDS

LG PJ350 PLASMA _ Z-SUSTAIN BOARD _ Z-BIAS ADJUSTMENT & DISASSEMBLY OF CIRCUIT BOARDS





The Z-Sustain cannot be run 'stand alone' in the 42T1 panel models.

  • Operating Voltages Power Supply Supplied VS M5V Routed through Control Board Y-SUS Supplied 18V Routed through Control Board Developed on Z-SUS Z Bias
  • The Z-SUS (in combination with the Y-SUS) generates a SUSTAIN Signal and an ERASE PULSE for generating SUSTAIN and DISCHARGE in the Panel.  This waveform is supplied to the panel through two FPC (Flexible Printed Circuit) connections P4 and to the Z-SUB P3 to P2 and to P1.

TIP: The Z-Bias (VZB) Adjustment is a DC level adjustment. This is only to show the effects of Z-Bias on the waveform.

 Z-SUSTAIN BOARD

Z-BIAS ADJUSTMENT

  • Read the Voltage Label on the panel when adjusting


  • Set should run for 15 minutes, this is the “Heat Run” mode. Set screen to “White Wash” mode or 100 IRE White input. All SMPS adjustments should have been completed.

  1. Place DC Volt meter between VZB TPs.
  2. Adjust VZB (Z Bias) VR1 in accordance with your Panel’s voltage label.

SMPS BOARD REMOVAL
  • Disconnect the following connectors: P811, P813 and SC101. Remove the 8 screws holding the SMPS in place. Remove the board. When replacing, be sure to readjust the Va/Vs voltages in accordance with the Panel Label. Also, re-confirm VSC, -Vy and Z-Bias as well.
Y-SUS BOARD REMOVAL Y-DRIVE BOARD REMOVAL
  • Remember to be cautious of ESD as some semiconductors are CMOS and prone to static failure. Disassembly Procedure for Circuit Board Removal Remove the Left Vertical Brace. 4 screws, 2 metal tap and 2 plastic tap. Disconnect the following connectors: P201, P203, P206, P211 and Ribbon Cable P101. To remove P101, lift up on the locking mechanism and pull the ribbon cable out. Remove the 16 screws holding the Y-SUS in place. Do not run the set with P211removed. Remove the Y-SUS board. When replacing, be sure to readjust the Va/Vs voltages in accordance with the Panel Label. Confirm VSC, -Vy and Z-bias as well.  [Note: The Y-SUS does not come with the connector to the Lower Y-Drive]

Y-DRIVE BOARD REMOVAL
  • Y-SUS does not come Disconnect P101~P106 Connectors to the Panel Remove P106 by lifting up on the locking mechanism and pull the ribbon cable out. Do not run the set with P106 connector removed. Remove the 7 screws holding the Y-Drive board in place. Lift up slightly, the slide to the left. Remove the Y-Drive Board.  [Note: Y-SUS, Z-SUS and Y-Drive boards are mounted on board stand-offs that have a small collar. The board must be lifted slightly to clear these collars. Behind each board are “Chocolate” (dense rubber like material) that act as shock absorbers. They may make the board stick when removing. The with the connectors between the Y-SUS and Y-Drive]

Z-SUS BOARD REMOVAL
  • Disconnect the following connectors: P1 and P2, then P4 by pulling out the locking mechanism and pulling out the FPC to the panel. Note, slide a thin object (top side) between ribbon and connector to remove. Remove the 9 screws holding the board in place. Lift up slightly to clear the screw stand-offs and pull the Z-SUS upward to unseat P3/P2 from the Z-SUB board and remove the Z-SUS board. When replacing, be sure to readjust the Va/Vs voltages in accordance with the Panel Label. Confirm VS, -Vy and Z-bias (VZB) as well.

Z-SUB BOARD REMOVAL
  • Remove the two screws in the Z-SUB board. Remove P1 by pulling out the locking mechanism and pulling out the FPC to the panel, See note above concerning P4 removal. Pull down and remove Z-SUB.

MAIN BOARD REMOVAL
  • Disconnect the following connectors: P703 LVDS and P301 (press gently inward on the locking tabs) and pull out, P704 and P801. Remove 1 screw in the decorative plastic piece and remove. Remove the 4 screws holding the Main board in place and Remove the board.

CONTROL BOARD REMOVAL
  • Disconnect the following connectors: P121 LVDS, P101 Ribbon and P102. Then P161, P162 Ribbons by lifting up the locking tab. Remove the 1 screws holding the Control board in place. Lift up the bottom and pull down to unseat it from the two metal supports at the top and Remove the board. Pay attention to the top right back side of the board. There is a piece of rubber (Chocolate) that may fall off. Be sure to replace the rubber piece.

FRONT IR & KEY PAD REMOVAL
FRONT IR/INTELLIGENT SENSOR and POWER BUTTON:


  • Disconnect P100 and P101. Note: P101 is a ribbon connector. Lift up the locking mechanism and slide the ribbon cable out. Remove the Board by lifting up on the top tabs, lift the board and remove.
KEY PAD:
  • The Key Pad is a thin strip of static sensitive material attached to the front glass. It is not removable.

X-DRIVE CIRCUIT BOARD REMOVAL
  • Make sure AC is removed. Lay the Television down carefully on a padded surface. Make sure to use at least two people for this process so as not to flex the panel glass.
  • Remove the Stand (4 Stand Screws were removed during back removal).
  • Disconnect the two connector on the left side of the Main board, P704 and P801. d) Remove the Stand Metal Support Bracket (5 Screws) 2 Plastic tap thread and 3 Metal thread.
  • Remove the two Vertical support Braces marked “E”. [Note: There are 4 Screws per/brace, 2 Plastic tap thread and 2 Metal thread]. (Note, the right brace has a Grounding wire from the AC input which must also be removed).
  • Remove the 7 screws holding the Heat Sink. (Warning: Never run the set with this heat sink removed). To remove the heat sink, lift up to release the tacky Chocolate (heat transfer material) and slide the heat sink to the left to clear the connector wires on the right side. [Note: There are three large pieces of conductive tape on the heat sink that must be removed. Also, note that there several pieces of Chocolate heat transfer material attached all the way across the underside of the heat sink. There is a mark on either side of the tape on the heat sink which shows its locations.]

X-DRIVE LEFT & X-DRIVE RIGHT REMOVAL
  • Disconnect all TCP ribbon cables from the defective X-Drive board and all other Ribbon cables going to the board. Remove the (3 Left or Right X) or (5 Center X) screws holding the defective X-Drive board in place. Remove the board. Reassemble in reverse order. Recheck Va / Vs / VScan / -VY / Z-Drive.
Posted By: FRANK at 02:22
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