Technical description and composition of the PHILIPS 20PF7835 TV, type of panel and applicable modules. The composition of the modules.PHILIPS
Model: 20PF7835 / 58
Chassis / Version: LC13E AA
Panel: LC201V02-A3
Inverter (backlight): T501044.00 rev2
PWM Inverter: OZ960S (20H)
MOSFET Inverter: AO4600 (8)
Power Supply (PSU): adapter 24v 5a AD3591
PWM Power: MC34063
MainBoard: 3139-123-5712.2
IC MainBoard: TDA8885H, MSP3410G
Tuner: UR1316 / A I H-3
Control: RC19335015 / 01 3139 238 05701
Technical Specifications 20PF7835
PHILIPS 20PF7835
General recommendations for repairing TV LCD
Repair of the PHILIPS 20PF7835 / 58 TV is advisable to start with a careful external examination. In this case, both external and internal components of the device should be inspected. Many visible changes make it possible to determine the future direction of troubleshooting and localization of the defect. Experienced repairmen are often aware of the causes of the defect and the possible consequences, for example, from ring cracks in the soldering of the leads of the elements, as well as from swollen capacitors or resistors burnt to coal dust and other external indirect signs.
If the power adapter 24v 5a AD3591 fails, the external manifestations may be different, for example, PHILIPS 20PF7835 / 58 does not turn on at all and there is no indication of the indicator lights on the front panel. When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. When it is broken, the power switch and rectifier bridge diodes should be checked for avalanche (thermal) breakdown.
It should be borne in mind that in the repair practice it is extremely rare that key transistors of the N-FET type fail for no reason that should be looked for by checking other components, for example, a breakdown of the key can provoke faulty elements of the damper circuits, either dried electrolytic capacitors or dangling resistors of the primary circuit of the PSU, involved in the stabilization process. In this case, all semiconductor elements of the strapping of the ON 34063 PWM controller chip are subject to verification, which it is desirable to verify by replacement.
In cases using a power module with an active KKM, troubleshooting is sometimes somewhat more complicated.
If the PHILIPS 20PF7835 / 58 does not have an image, but there is sound and the TV is controlled by the remote control, a malfunction in the display backlight nodes is likely. The lamps or the power converter - inverter may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the inverter, and check the LCD lamps by connecting external and obviously serviceable for diagnosis to the connectors.
When repairing the T501044.00 rev2 inverter, often for diagnostics it is necessary 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.
It should be remembered that in such cases there is a risk of failure of the power elements of the inverter and to take special care. After carrying out repairs, the protection circuit must be restored for further safe operation of the TV.
Once again, remind users! Attempts to independently repair the PHILIPS 20PF7835 / 58 TV without the appropriate qualifications and experience can lead to its complete non-repairability!
Service manual and schematic diagram 20PF7835/58 Chassis LC13E AA
The appearance of MainBoard 3139-123-5712.2 is shown in the figure below:3139-123-5712.2
3139-123-5712.2 can be used in televisions:
PHILIPS 13PF7835/58 (Panel LC130V01-A2), PHILIPS 20PF7835/58 (Panel LC201V02-A3).
Main features of the PHILIPS 20PF7835 device:
Installed matrix (LCD panel) LC201V02-A3.
To power the backlight, the inverter T501044.00 is used, it is controlled by the OZ960S PWM controller (20n). As power elements of the inverter, keys of the AO4600 type are used (8).
To power all the internal components of the PHILIPS 20PF7835 TV, an external adapter type 24v 5a AD3591 is used using MC34063 chips.
MainBoard - the main board (motherboard) is a module 3139-123-5712.2, using TDA8885H, MSP3410G and others.
The tuner UR1316 / A I H-3 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: LG.Philips LCD
Model: LC201V02-A3N8
Type: a-Si TFT-LCD, Panel
Diagonal size: 20.1 inch
Resolution: 640x480, VGA
Display Mode: IPS, Normally Black, Transmissive
Active Area: 408x306 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 450 cd / m²
Contrast Ratio: 350: 1
Display Colors: 16.7M (8-bit)
Response Time: 12/13 (Tr / Td)
Frequency: 60Hz
Lamp Type: 6 pcs CCFL Without Driver
Signal Interface: Parallel RGB (1 ch, 8-bit), 41 pins
Voltage: 12.0V
