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 !

Saturday 14 December 2019

LG LHD625 DVD HOME THEATER SYSTEM TROUBLESHOOTING – PCB LEVEL – FIRMWARE UPDATE PROCEDURE, SMPS AND AUDIO OUTPUT SCHEMATIC AND VOLTAGES

DVD Home Theater System LG LHD625 troubleshooting – PCB level – firmware update procedure, SMPS and Audio output schematic and voltages


LG (LHD625, S63S1-S, S63T1-C, S75T1-W) AMPLIFIER: Stereo mode 167 W + 167 W (3 Ω at 1kHz)
Hidden key mode
DISPLAY SYSTEM INFORMATION
1) Change function to DVD/CD by pressing input key, and wait until home menu is shown.
- Do not insert disc or USB at the set.
2) Go to SETUP menu by pressing SETUP button in HOME menu.
3) Move highlight at "DISPLAY > TV Aspect -> 16:9".
4) Press "1 > 3 > 9 > 7 > 1 > 3 > 9 > ENTER" in order.
5) and then, system reset menu is displayed
6) Power off and on by pressing POWER key.
EEPROM EDIT
1) Change function to DVD/CD by pressing input key, and wait until home menu is shown.
- Do not insert disc or USB at the set.
2) Press "PAUSE > 1 > 4 > 7 > 2" in order.
3) and then, option setting menu is displayed.
You can see 10 bytes option value.
4) Move a cursor by pressing Arrow < > key.
5) Press number 0 ~ 9, character a ~ f (1 ~ 6 for a while) for more than 5 seconds
6) Press "PAUSE" key to exit option setting menu.
After change option value, you need to make system reset.
DOOR LOCK / UNLOCK
1) Press Front “STOP” + Remote control “STOP” for more than 5 seconds.
2) “LOCKED” / “UNLOCKED” display on the VFD.
FIRMWARE UPGRADE
MPEG
1) Copy firmware to USB (Do not change file name).
Ex) LG_LHD655LD7_1501051.rom
2) Change function to DVD/CD by pressing input key, and wait until home menu is shown.
3) Inset USB device which includes firmware.
4) Firmware is detected automatically and then, shows blue screen in TV.
 If home menu is maintained after inserting USB, press music icon.
5) Take off the USB and press PLAY key.
6) and then, upgrading get started.
- Do not turn off the set or uplug the unit from mains power sourse until upgrade is finished.
7) After finishing firmware upgrading, set will restart automatically.
8) Power off and on again by pressing POWER key.
AUDIO MICOM
1) Copy firmware to USB (Do not change file name).
Ex) LHD655_1501050.HEX
2) Change function to DVD/CD by pressing input key, and wait until home menu is shown.
3) Inset USB device which includes firmware.
4) Firmware is detected automatically and then, shows blue screen in TV.
 If home menu is maintained after inserting USB, press music icon.
EQ
1) Copy firmware to USB (Do not change file name).
Ex) EQ_PRG.BIN
2) Change function to DVD/CD by pressing input key, and wait until home menu is shown.
3) Inset USB device which includes firmware.
4) Firmware is detected automatically and then, shows blue screen in TV.
 If Home menu is maintained after inserting USB, press music icon.
5) Upgrading is started.
- Do not turn off the set until upgrade is finished.
- Do not pull out the USB device using firmware upgrading.
6) After finishing firmware upgrading, set will be turned off.
NO POWER PROBLEM
No power problem occurs when you power on the unit.
Fuse & Bridge diode
Replace F901, BD901 on SMPS board.
1) Look at the physical state of fuse F901.
2) Check the bridge diode BD901.
No power problem occurs when you power on the unit.
VFD, 14 VA, 5.5 VA
Replace D922, D923, D924, D925, D926, D927, IC901.
Case 1) FLD abnormal: Check D950, D951, ZD951, ZD952, FR950 and replace it.
Case 2) 5.5 VA abnormal: Check D952, D953 and replace it.
Case 3) 14 VA abnormal: Check D955, D956 and replace it.
Case 4) All voltage abnormal: Check IC901 and replace it.
NO BOOTING WHEN YOU TURN THE UNIT ON, NO MESSAGE ON FRONT PANEL
When you turn on your set, it will blank / no message on front panel, and stand-by LED no working.
IC103 (No 3.3 VA)
Replace IC103 on MAIN board.
 1) Check 3.3 VA of IC108.
2) If 3.3 VA is abnormal, please check 5.5 VA of IC103 pin1.
3) If 5.5 VA is OK, but 3.3 VA is abnormal, replace IC103.
When you turn on your set, it will blank / no message or Welcome on front panel, and it will not boot-up.
IC105 System 3.3 V (No System 3.3 V)
Replace IC105 on MAIN board
How to troubleshoot
1) Please check 5.5 VA of IC105 pin3 (VIN).
2) If 5.5 VA is abnormal,  check SMPS 5.5 VA.
3) If 5.5 VA is OK, but 3.3 V is abnormal at the IC105 pin6 (VOUT), replace IC105.
When you turn on your set, it will display “WELCOME” on front panel, and it will not boot-up normally.
Xtal 500
Replace X500 on MAIN board.
1) Check the soldering status of 27 MHz crystal (X500).
2) Check the frequency of 27 MHz crystal (X500).
3) If the crystal doesn’t oscillate, replace X500.
4) After changing it, if the set is still not booting :
- Check Serial Flash IC (IC504)
- Check SDRAM IC (IC503)
- Check MT1389 IC (IC500).
When you turn on your set, it will display “WELCOME” on front panel, and it will not boot-up normally.
IC503 (SDRAM MEMORY)
Replace IC503 on MAIN board.
1) Check 3.3 V IC503.
2) If it doesn’t work even though IC105 is no problem, IC503 (DDR memory) could have problem.
3) After changing it, if the set is still not booting : Check MT1389IC
When you turn on your set, it will display “WELCOME” on front panel, and it will not boot-up normally
IC500 (MPEG IC)
Replace IC500 on MAIN board.
1) Check 1.2 V of C510 on main board.  Check 3.3 V of C548 on main board.
2) If it doesn’t work even though IC105 is no problem, IC500 (MT1389) could have problem.
BAD HDMI VIDEO / AUDIO OUTPUT
When unit is connected to HDMI TV using HDMI cable, picture shows bad color, no output or mixed color on the screen. But component output is OK.
JK501 (HDMI JACK)
Replace JK501 (HDMI Jack)
1) Check JK501 pin soldering.
2) If there is short soldering on pin JK501, re-soldering pin JK501.
3) If problem still occurs, check HDMI data.
- If all data OK, replace JK501.
- If data NG, check set on BD mode :
Replace IC500
NO AUDIO FROM SPEAKER
When unit is connected to speaker, no audio from speaker
IC601 (PWM IC)
Replace IC601 (PWM IC).
How to troubleshoot
1) Check IC601 pin soldering.
2) If there is short soldering on pin IC601, re-soldering pin IC601.
3) If problem still occurs, check AMP IC (IC700, IC701, IC702).
- Check IC700, IC701, IC702 pin soldering.
- If soldering OK, check the AMP heat sink :
Replace IC700, IC701, IC702
BT connection error
BT module
Replace BT module on Main chassis
1) Check your BT device. Make sure that BT function is on-state.
2) If it is OK, please check the CN201.
3) If there is soldering problem, please re-soldering pin CN201.
4) If after re-soldering problem still occurs, replace BT module.
5) If problem still occurs after change BT module, check MT1389 IC (IC500)
SMPS – Audio output and voltage chart
Posted By: FRANK at 08:53
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