Cheap Fix On Completely Dead 24 Inch Salora 24LCF-5000TDW TV-DVD Player
Recently I examined a 24 inch Salora 24CFL-5000TDW TV with integrated DVD player that didn’t work anymore. Before it completely refused to operate my brother already had noticed that the TV started to behave erratic by suddenly switching off, or it simply refused to switch on.
I previously had examined this TV in the past because my niece heard a high frequency tone coming out of this TV. A high frequency my brother and I at our age are incapable to hear. Often these high pitch tones are generated by HF transformers or coils, so therefore I glued hotmelt over the powerboard transformers and coils. But that apparently hardly made any difference. And that was at least about 3 years ago until the Salora now no longer worked.
Next photo shows the still perfectly working powerboard that converts the 230V AC into 12VDC. From which all other voltages including the 3.3V , the 1.85V and the 5V needed for CPU, BIOS chip, and Audio Amplifier are derived. That board also supports feeding the Salora TV from 12V from a Car battery or other 12V power supply. And the ON-switch and all fuses were still fine!
This power board is the second board in the middle of 3 boards in total. The board on its left is the DVD player. And the 3th board on the right is the Video/Amplifier board.
After further investigation we only measured the 12VDC powering the Videoboard with Audio amplifier circuit. But the 2 LM1117 smd regulator IC’s and the BIOS chip were completely powerless.
And we know from computers that without any voltage (mostly 3.3V on pin 8) on the here 25L3205 sop8 smd IC the Videoprocessor can’t work at bootup. Because the processor is deprived from any bootup data and doesn’t know how to startup the TV. Which also happens when the firmware in this flashable serial eeprom BIOS is corrupted somehow. And the here unknown video processor likely is fed from a lower voltage which is usual in computers. And is probably why there are here two LM1117 IC’s used. Following photo shows the mounted Video board before removing. The Powerboard left from it is here already removed.
Next is the componentside of this Videoboard shown. With Bios and Video CPU below the Scart.
And on the right below the Scart port both above mentioned LM1117 regulators. The top one normally feeds the Bios with 3.3V DC, and the second one regulates the 1.85V DC voltage. But as mentioned none of them worked (yet). We first had to examine why.
Pay special attention to the jumper on the right from the LCD cable above. The 3 pin jumper switches in the given down position to 5V.
And in the not used here upper position to 3V. The 2 pins right from it are just GND and +12V DC. In next photo these connectors are right from both e-caps shown again.
And all next shown IC’s are all powerless/inactive. Only 12V DC coming in was measured.
First above on the left shown the BIOS, and unknown sop8 AAU0FA and AAW0BA (?) IC’s that probably are somekind of step-down converters because the 12V goes in but no voltages come out (in this case at least 5V is needed) , and shown next are both LM1117 regulators. Also next IC’s and their function couldn’t be determined in the online available SMD code databases. Although the CU0FA in next photo may be a SY8009A or B step down regulator chip this would not make sense if its max input voltage is only 6V DC in this TV.
So testing or replacing any of the chips in the not working TV board circuit is hard if not impossible without knowing the functions and the pinsetting of these chips. Especially since no service manual or schematic is available for this TV anywhere online. Next photo shows a closer view on the 3 pin 5V voltage jumper selector (of which 3V is not selected), and the 2 pin 12V and GND connector below it.
It also clearer shows both dead likely 12V step-down converters sop8 IC’s right under both coils, as earlier mentioned the marked AAU0FA and AAW0BA chips. Maybe both unknown sop8 chips are with the coils used for the Left and or Right Audio channels if they are not step-down converters. We are however sure that the square chip with marking R2A15120 is here the Audio processor. See next photo.
And the audio output connector close to it also uses 4 coils that obviously are for the audio output lines.
Nevertheless against all odds with a rather genious trick, we are proud to say, we got this completely dead Salora Television and DVD player set ready working again!
How we did this you may ask?
By simply feeding-in the 5V power externally on the TV board where the mentioned 3 pin voltage selector selects the 5V position!
And by testing this by using our WanPtek adjustable, stabilised and short circuitproof upto about 30V adjustable (my brothers WanPtek NPS306W goes up to 6A, mine goes a bit further up to 10A. And my new 120V WanPtek limits to about 3A which is also about 360 Watt!). My brother’s WanPtek also shows the Power consumption, besides the standard Voltage and the Amperage on its front display. It showed the Salora finally worked again splendidly the moment we fed in the 5V externally feeding a current of 1.66A into the TV. Of course we also still powered the TV at the same time from the 230V AC Power to keep also the 12VDC voltage working. Because also the backlight and other circuits need the 12V power.
After that also the Bios got its 3.3V on pin 8, and the LM1117 marked U39 worked giving a lower voltage derived out of the 3.3V voltage coming from LM1117/U5. The Video board worked again, including the LCD and its backlight.
And to make this TV complete again we have several cheap options. Like this DC/DC converter from comopez store. That easily fits inside the TV and only costs about four dollars free shipping.
We simply feed this converter from our second Powerboard that supplies the necessary 12V DC. And if 5V 2.5A is not enough we can select one from seller AOKIN DivMaker store that goes upto max 10A:
Albert van Bemmelen, Weert, The Nethelands.
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Note: You can read his previous article on Samsung TV With Flickering Backlight Repaired