Manta 32LHN28L TV
Cheap 32" TV from 2018. Not supporting H.265, but still useful as a monitor for a PC or gaming console. Specification:
- DVB-T2+C (but no H.265)
- LED backglight, 3.8 kg
- 1366x768
- 180cd/m2
- power consumption < 48W
- 2xHDMI, VGA, composite, component inputs
- 200x100 mounting on the back using M6 screws
- PVR (recording) function (USB)
- SPDIF coaxial audio output
After connecting the power LED on the front was turning red, but its state was not changing when trying to turn on TV.
https://www.elektroda.pl/rtvforum/topic3879975.html describes similar symptoms. In my case output voltage of 3.3V regulator was equal to ~2.6V when measuring. Replacing 1117-3.3 (original: AS1117L-3.3, new one: MT1117-3.3 that I got from broken monitor) regulator fixed the issue.
Is this issue systemic? Assuming that voltage regulator might degraded due to temperature, I've added very small radiator to it to prolong its life.
Board: CV3663AH-Q42. I have not found schematic, only block service manual CV3663BH which seems to be different in many ways (e.g. using AD52060 audio amplifier).
Apparently there are two variants with different panels, this one has HV320WHB-N85.
Speaker connector on the right.
MSD3663 MStar SoC.
SRC65R600E high voltage N-channel MOSFET.
25Q64 SPI Flash.
BIT3267 current mode LED driver.
RDA3118E28 class-D audio amplifier.
This PCB can be also used with two USB ports (double socket) instead of a single one.
MBR10100BCT Schottky diode.
Two 1117 regulators: 3.3V and 1.5V.
Faulty voltage regulator.
New voltage regulator with improvised radiator.
Speakers are basically hanging in the air, not touching anything except for rubber pads.
It won't win any audio quality contest.
AT6861AAQ DC-DC converter on T-con board.
HX8872.
IML7991 - I2C interfaced digitally programmable gamma buffer and digitial VR with integrated VCOM buffer and embedded programmable non volatile memory.
ICN7211 - it looks like some sort of fast and high power operational amplifier.
MDD1051 MOSFET, 150V/28A.
After the repair.
Testing with PC
This TV seems to have problems when connected to PC. When using HDMI it seems to support only 1080p resolution, forcing content scaling which in turn resulted in poor font quality. VGA input works better, but still it is not the best quality - probably worse than any dedicated monitor. It might be fine for watching movie or playing some game, but I'm not sure if it would be suitable for longer work with text.
Connecting to other PC showed more weird issues: VGA resolution was detected as 1360x768, auto adjustment (size/position) function also did not work correctly.
Manufacturer has a page with firmware, but the only one for this model seems to be intended for a variant with other panel (LSC320AN).
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