Friday, 21 August 2020

REPAIRING / SERVICING TV ROLSEN RCL-900

Technical description and composition of the ROLSEN RCL-900 TV, panel type and modules used. The composition of the modules.
ROLSEN
Model: RCL-900
Panel: HN CMI-9D
T-CON: KSD951S-S202KD-MAIN-V1.0
Inverter (backlight): 8202KD-9D.PCB
PWM Inverter: OB3HT (2)
Power Supply (PSU): adaptop 10v
MainBoard: MAIN_PCB
IC MainBoard: 25Q16BS1G, 2952A, E13c1, MC6019,5218 (ES348314), KSD951S-8202KD-V1.0, SPHE8202K
Appearance
ROLSEN RCL-900
General recommendations for TV LCD repair
Repair and diagnostics of any electronic device, in particular ROLSEN with a chassis, it is advisable to begin with a careful external examination of the internal and external elements. Specific external damage to some elements can sometimes indicate further actions to determine the malfunction of the TV and localize the defect before starting the necessary measurements. Electrolytic capacitors of filters with a swollen case, as well as ring cracks formed in the soldering of the leads of heating elements or a layer of coal on burned out resistors sometimes prompt the repairman about the causes of the malfunction and the possible consequences.
In the absence of any signs of operability, when the ROLSEN RCL-900 does not turn on and does not signal anything with the control lamps on the panel, there is a possibility of malfunction of the adaptop 10v power supply module of the TV. With the same manifestations, the power regulator of the control processor on the motherboard may be faulty. Diagnostics and repair of the common power supply should always begin with checking the mains fuse and the condition of the electrolytic capacitors of the secondary rectifier filters. Defective and swollen capacitors should be replaced with new ones. If the fuse breaks, it is advisable to check for breakdown, first of all, all the power semiconductor elements of the converter and the diode bridge of the mains rectifier, as well as the large electrolytic capacitor of the mains rectifier filter.
As a rule, switches in switching power supplies (SMPS) are quite reliable and rarely fail without reasons that should be looked for by checking other components of the circuit - electrolytic capacitors, resistors and semiconductor elements of the primary circuit. The PWM microcircuit is checked by replacing it with a known good one.
If, when you turn on the TV, the image appears and immediately disappears, or is absent initially when turned on, but there is sound and other functions work, there is a high probability of a malfunction of the inverter (backlight power converter). In such cases, the lamps, the inverter and the common power supply module must be checked, in which the electrolytic capacitors of the rectifier filter supplying the inverter must be checked. It should be remembered that when the protection is turned off in order to diagnose a malfunction, there is always a risk of failure of the power elements of the inverter. After repair, it is imperative to restore all standard converter protection circuits.
Complicated repair of MB (SSB) board is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace elements 25Q16BS1G, 2952A, E13c1, MC6019.5218 (ES348314), KSD951S-8202KD-V1.0, SPHE8202K. Malfunctions in BGA chips are usually easy to detect by warm-up.

Remember! Attempts to repair the ROLSEN RCL-900 TV, 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!
The main features of the ROLSEN RCL-900 device:
Installed matrix (LCD-panel) HN CMI-9D.
Matrix control uses the Timing Controller (T-CON) KSD951S-S202KD-MAIN-V1.0.
To power the backlight lamps, the 8202KD-9D.PCB inverter is used, controlled by the OB3HT PWM controller (2).
The formation of the necessary supply voltages for all nodes of the ROLSEN RCL-900 TV is carried out by the adaptop power supply module, or its analogs.
MainBoard - the main board (motherboard) is a MAIN_PCB module, using chips 25Q16BS1G, 2952A, E13c1, MC6019,5218 (ES348314), KSD951S-8202KD-V1.0, SPHE8202K and others.