Saturday 21 December 2019

REPAIRING / SERVICING TV SAMSUNG LE22A454C1

Technical description and composition of the SAMSUNG LE22A454C1 TV, panel type and applicable modules. The composition of the modules.
SAMSUNG
Model: LE22A454C1
Panel: LTM220M1-L01
Inverter (backlight): integrated into PSU
PWM Inverter: SEM2005, STU3120
Trans Inverter: TM-0917
Power Supply (PSU): BN44-00232A IP-54135T
PWM Power: FAN7602B
MOSFET Power: 7N65C (FQPF7N65C)
MainBoard: BN41-01028B
IC MainBoard: SEMS01 0825B-L, K4D261638K-LC40, 25L1605AM2I (EM6A9160TSDA-5G)
Tuner: BN40-00116A
Technical Specifications LE22A454C1
SAMSUNG LE22A454C1
General repair guidelines for TV LCD
Any repair of electronic equipment begins with a careful external inspection of the device and troubleshooting. In this case, you should carefully examine all the elements of the SAMSUNG LE22A454C1 TV, both internal and external. Specific external damage can sometimes prompt further actions to determine the malfunction of the TV and localization of the defect before the necessary measurements and waveforms are taken. In some cases, faulty elements are visible to the naked eye, for example, charred resistors or swollen metal-ceramic capacitors, or electrolytic in rectifier filters. Ring cracks formed in the soldering of the terminals of transformers or heating elements of the circuit are also frequent sources of many malfunctions with a variety of external manifestations.
If the power supply module malfunctions, the external manifestations may be different, for example, SAMSUNG LE22A454C1 does not turn on at all and there is no indication of the indicator lights on the front panel. If the mains fuse is broken in the power supply, in most cases a breakdown of the power switch is detected, which can be integrated with the PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
If a breakdown of the power switch of the flyback converter of the power supply unit is detected, it should be remembered that it does not fail for no reason, which should be sought by checking other elements of the primary circuit - electrolytic capacitors, a PWM controller that can only be checked by replacement, as well as others semiconductor elements (diodes, transistors, zener diodes).
When using an active Power Factor Correction (CMC) circuit in the power module, the search for faulty elements is somewhat more complicated.
If, when you turn on the TV, the image appears and immediately disappears, or is initially absent when turned on, but there are sound and other functions work, there is a high probability of a malfunction of the inverter (power converter for the backlight). In such cases, the lamps, the inverter and the common power module are subject to verification, in which the electrolytic capacitors of the rectifier filter feeding the inverter should be checked.
When repairing the inverter, it is often necessary for diagnostics to turn off the protection, which, for the purpose of fire safety, turns it off in any emergency situation, for example, during a malfunction or uneven wear of the lamps, which makes it difficult to find a defect.
Turning off the 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.
It is advisable to start the repair of the BN41-01028B motherboard 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. When repairing an MB board, you need to check its components SEMS01 0825B-L, K4D261638K-LC40, 25L1605AM2I (EM6A9160TSDA-5G). Defective items should be replaced.
It should be remembered! Attempts to repair the TV SAMSUNG LE22A454C1, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!


Main features of the SAMSUNG LE22A454C1 device:
Installed matrix (LCD panel) LTM220M1-L01.
To power the backlight, a converter is used, combined with a power supply, controlled by a PWM controller SEM2005, STU3120. The transformer TM-0917 is installed in the inverter converter.
The necessary supply voltages for all nodes of the SAMSUNG LE22A454C1 TV are generated by the BN44-00232A power module or its analogs using FAN7602B microchips and 7N65C type power switches (FQPF7N65C).
MainBoard - the main board (motherboard) is a BN41-01028B module, using microchips SEMS01 0825B-L, K4D261638K-LC40, 25L1605AM2I (EM6A9160TSDA-5G) and others.
The tuner BN40-00116A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTM220M1-L01
Type: a-Si TFT-LCD, Panel
Diagonal size: 22.0 inch
Resolution: 1680x1050, WSXGA +
Display Mode: TN, Normally White, Transmissive
Active Area: 473.76x296.1 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 72%
Response Time: 1.3 / 3.7 (Tr / Td)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V