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 !

Monday 18 March 2019

LG - MCD606 (MCD606, MCS1306F) - TROUBLESHOOTING

LG - MCD606 (MCD606, MCS1306F) - TROUBLESHOOTING



NO POWER
FUSE & BRIDGE DIODE
Check and replace F901, BD901, TH901, TH903 on SMPS board.
  • Check if the fuse F901 is open or short-circuit.
  • Check if the bridge diode DB901 is short-circuits by over current with a digital multi meter.
  • Check if the NTC thermistor TH901 and TH902 is normal or open.
  • Check the Anode-Cathode Voltage of D951 with a digital multi-meter, it is normally 0.2 ~ 0.3 V. => If it doesn’t have any voltage, it’s destroyed. Replace it with a new one.
  • Check if ZD951 is short-circuits. => If it is short-circuit, and then replace it with a new one.
WHEN POWER ON, SET DO NOT BOOT
  • Check the 3.7VA to CN102, CN103, and CN104 in standby mode. => If there is no 3.7 VA, check the SMPS.
  • Check 5.6 V, 12 VA, FL+, FL- and 32 V when power on the set.   If the set doesn’t work regardless of what the KEY1 changes high to low while pressing the power button. X100 and X101 work normally but, if you cannot power on the set, replace the IC101 with a new one on the main board.
VFD IS NOT DISPLAYS
  • Check if 32 V, FL+ and FL- are output from SMPS to VFD via the MAIN board.
  • Check if the IC101 outputs VFD_RST, VFD_CLK, VFD_STB, and VFD_STB to the FRONT board.
  • Check if the VFD grid current amplifier circuit (Q301, Q303, Q304) on the FRONT board. Check the drive signal to the transistor’s base.
  • If the control signals from VFD (TP302, TP303, TP304) aren’t output; replace VFD with a new one. If the transistor doesn’t work, replace it.
MD DO NOT WORK
  • When no sound output in the CD function, you cannot listen to music reading data from a CD disc if the servo-motors in MD don’t work. This step is for checking the SPINDLE MOTOR among them.
  • SPINDLE MOTOR: check and replace IC407, IC408 on MAIN board.
  • Check the SPDO signal from Pin16 of IC407. If no signal, check 3.3V(RF) and X402.
  • Check the SP- & SP+ from IC408 to CN405 for driving Spindle motor. It is about 3.6 Vp-p.  If no signal, check +1.8 V and +5 V for IC408.
  • Check if the FFC cable is solidly connected between CN405 and MD.
  • Check the MD.  If the spindle motor is sort-circuit or has any trouble, it cannot rotate CD discs.  Check the function after changing another MD.
Posted By: FRANK at 04:13
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