Technical description and composition of the LG RZ-20LA66 TV, panel type and applicable modules. The composition of the modules.LG
Model: RZ-20LA66
Chassis / Version: ML-024D
Panel: 20 inch
Inverter (backlight): 6870VM0444C (3)
PWM Inverter: OZ960S,
MOSFET Inverter: 8958A (8)
Trans Inverter: 6170VH0002A KE0352
Power Supply (PSU): 6870VM0444C (3),
PWM Power: STR-W6853,
MainBoard: 6870VM0444C (3)
IC MainBoard: TPA3004D2, MP1583DN (8) DC-DC, VCT49xyF
Tuner: 6700PF0002A TAFH-S312D
Technical Specifications RZ-20LA66
LG RZ-20LA66
General recommendations for repairing TV LCD
Repair and diagnostics of any electronic device, in particular LG with the ML-024D chassis, it is advisable to start with a careful external examination of internal and external elements. According to some external signs of a change in the state of some elements, it is sometimes possible to make assumptions about the nature of the defect, as well as determine the further direction of the troubleshooting. In some cases, faulty elements can be seen with the naked eye, for example, charred resistors or swollen metal-ceramic capacitors, or electrolytic in rectifier filters. Ring cracks formed in the soldered terminals of transformers or heating elements of the circuit are also frequent sources of many malfunctions with a variety of external manifestations.
In cases where the LG RZ-20LA66 TV does not turn on, does not respond to the remote control and buttons, no indicators on the front panel light up or blink, and there are no sounds and no signs of operability when turning on, the power supply module 6870VM0444C is most likely faulty (3 ), or there is no processor power on the motherboard (a typical defect of some LG TVs). In the general case, first of all, it is necessary to check the electrolytic capacitors of the secondary rectifier filters and the fuse at the input of the network. If it is broken, then you should check for breakdown of the PN junctions of the rectifier bridge diodes and the key transistor of the converter, which can either be on a separate radiator or integrated with a PWM controller in a common chip. Possible options.
Power switches in switching power supplies (SMPS) fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The reason may be a malfunction of the PWM controller chip STR W6853, which can only be checked by replacing it with a new or obviously working one.
If the LG RZ-20LA66 TV does not have an image, but there is sound, the malfunction should be sought in the backlight lamp power converter (inverter). It is also necessary to check the serviceability of the electrolytic capacitors of the filter of the secondary rectifiers of the BP (power supply) for an overstated ESR. When disabling protection for diagnostic purposes, it must be remembered that in this case there is a risk of failure of the power elements of the inverter. Upon completion of the diagnosis, all regular protection circuits should be restored.
Repair of the 6870VM0444C motherboard (3) must begin with the diagnosis and verification of all linear stabilizers or power converters of its microcircuits. Sometimes it may be necessary to update the software (software) - flashing FLASH or EEPROM. In some cases, it is necessary to check or replace (if necessary) the elements of the MB board (SSB) - TPA3004D2, MP1583DN (8) DC-DC, VCT49xyF, tun 6700PF0002A TAFH-S312D. In cases where the BGA processor is used, its malfunction is usually detected by the local heating method.
Attention! For users and owners of RZ-20LA66 TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-serviceability of the device.
Service manual / schematic diagram -------------> LG RZ-20LA66 Chassis ML-024D
Service manual / schematic diagram -------------> LG RZ-20LA66 Chassis ML-041B
Installed matrix (LCD-panel) 20 inches.
To power the backlight, the inverter 6870VM0444C (3) is used, it is controlled by the PWM controller OZ960S,. The transformer 6170VH0002A KE0352 is installed in the inverter converter. Keys of type 8958A (8) are used as power elements of the inverter.
The necessary supply voltages for all nodes of the TV LG RZ-20LA66 are formed by the power supply module 6870VM0444C (3), or its analogs using microcircuits STR-W6853,.
MainBoard - the main board (motherboard) is a 6870VM0444C module (3), using TPA3004D2, MP1583DN (8) DC-DC, VCT49xyF, and others microcircuits.
Tuner 6700PF0002A TAFH-S312D provides the reception of television programs and tuning to channels.
