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!

©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 !

Friday, 1 February 2019

LG RF-21FB20R, LG RT-21FB20R - 21 INCH CRT TV – SERVICE MODE, OPTION ADJUST, CIRCUIT DIAGRAM

LG RF-21FB20R, LG RT-21FB20R - 21 inch CRT TV – Service mode, option adjust, circuit diagram

LG RF/RT-21FB20R/RE/RQ/RX/RW, RF/RT-21FB20V/VE/VG/VQ/VW - MC-019A CHASSIS 
 Used ICs: LA7016, TDA9361/81/70, MSP34100, TDA9859, TDA6107Q, STR-F6654R, LA7840 
Adjustments
Test Equipment required
1. Multimeter (volt meter)
2. Oscilloscope
3. 10:1 PROBE
4. Color Analyzer
CDL Data Adjustment(LINE SVC-0)
1) Press the SVC button to get into the SVC-0 Mode.
2) Press the Channel UP/DOWN button to select CDL12.
3) Press the Volume UP/DOWN button until the CDL data is the same as the Table below.
4) Press the OK(i) button to memorize the data.
OPTION Data Adjustment(OPTION-1,OPTION-2)
1) Press OK buttons on both TV set and Remote Controller at the same time to get into SVC mode.
2) Press the Yellow button several times to find OPTION-1 or OPTION-2.
3) Input the correspond OPTION data referring to Table below with the numeric buttons.
4) Press the OK(¡) button to memorize the data.
Screen Voltage Adjustment
1) Connect the probe of oscilloscope to the RK (Red Cathode) of CPT Board.
2) Set the oscilloscope to 50V/div and 20Us/div and after putting GND line upon the lowest grid line of the scope by pressing GND button, enter into DC mode.
3) Tune the TV set to receive a PAL-B/G 05CH.
4) Adjust Screen Volume of FBT so that the waveform is the same as below.
White Balance Adjustment.(LINE SVC-0)
This adjustment should be performed after screen voltage adjustment.
1) Tune the TV set to receive an 100% white pattern.
2) Press OK(¡) buttons on TV set and remote controller at the same time to get into SVC mode.
3) Press Yellow button on remote controller. (Standard mode)
4) Press Channel UP/DOWN button for desirous function adjustment.
5) Adjust VOL+ or VOL-button in each status of "RG--"/"BG--" for
X=272¡ 8, Y=288¡ 8 with color analyzer.
(Europe Model: X=288¡ 8, Y=295¡ X=272¡ 8, 11,000K)
Schematic [Full]
Power and Deflection section
Deflection Adjustment Procedure
VL (Vertical Linearity)
Adjust so that the boundary line between upper and lower half is in accord with geometric horizontal center of the CPT.
VA (Vertical Amplitude)
Adjust so that the circle of a digital circle pattern may be located within the effective screen of the CPT.
SC (Vertical “S” Correction)
Adjust so that all distance between each horizontal lines are to be the same.
VS (Vertical Shift)
Adjust so that the horizontal center line of a digital circle pattern is in accord with geometric horizontal center of the CPT.
HS (Horizontal Shift)
Adjust so that the vertical center line of a digital circle pattern is in accord with geometric vertical center of the CPT.
Press the OK(¡) button to memorize the data.
Convergence Adjustment
This procedure DOES NOT apply to bonded yoke and picture tube assemblies.
Do not use screen magnets during this adjustment procedure. Use of screen magnets will cause an incorrect display
Posted By: FRANK at 01:00
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