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Long story short, I want to run a TV off of 12v as cheaply as possible. I saw someone pop open a 32 inch TV and bypassed the AC power supply and powered the main board directly with a 12v connector. The TV I'm looking at here, appears to take the same connector from the video: https://www.walmart.com/ip/onn-32-Class-HD-720P-LED-Roku-Smart-Television-100012589/314022535

This is the main board: https://www.shopjimmy.com/onn-515c90111m07-m22058-mt-main-board-power-supply-for-100012589/#mz-expanded-view-852366679416

Now the 12V connection used was the JST 2 pin connector. The issue is, from what I'm learning about volts, amps, resistance, etc is that the provided 26AWG wire is not enough to support this 12v application safely. Am I missing something? Anyone think this is possible? What options do I have other than buying a real expensive 12v TV?

It's believed to be a JST 2 pin connector on the mid left section of the board, in the centre of the following picture: Zoomed in PCB picture centred on 2-pin 12 V connector

I basically want a TV for a van setup. My other comment explains that I would want sound to actually hear stuff vs the 12 V computer monitor I have laying around. The monitor takes 12 V 2 W, so my interpretation of the TV would be a bit more watts.

Video of it being done (allegedly): https://youtu.be/FnseanH8Amk?si=3m2fuj2z8EJenmqK

higher voltage: https://youtu.be/1AFbVR4eSXs?si=xvI59xf-KUWsbJZt

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  • \$\begingroup\$ How much power does it consume? \$\endgroup\$
    – winny
    Commented Apr 25 at 10:18
  • \$\begingroup\$ which video? Which connector?? \$\endgroup\$
    – Marcus Müller
    Commented Apr 25 at 10:21
  • \$\begingroup\$ As noted in a comment on an answer, the question is a bit-unclear about which "2 pin connector" is proposed to be used to supply 12 V. Consider an edit to the question to include an annotated picture of the PCB with which connector is being proposed to supply 12 V. \$\endgroup\$
    – Chester Gillon
    Commented Apr 25 at 18:01
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    \$\begingroup\$ The wire size has absolutely nothing to do with the voltage, and absolutely everything to do with the current. You've told us the voltage, but you didn't say a word about the current. \$\endgroup\$
    – Hearth
    Commented Apr 25 at 18:36
  • \$\begingroup\$ I’m genuinely curious to know the motivation for doing this, if you don’t mind sharing. Is it for running it in a automobile? \$\endgroup\$
    – Ste Kulov
    Commented Apr 25 at 23:05

2 Answers 2

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The rated power consumption of this device is 50W. So at 12V you should allow for a bit more than 4A. Something like AWG20 would be appropriate. There should be other points on the PCB where the 12V is available and wires could be attached. A 2mm pitch JST-style connector is unlikely to be good for 4A even if you could get an AWG20 wire to fit.

I have no opinion on whether this will work properly in this particular case, and it certainly runs a risk of destroying the TV (for example, if the input is not actually 12V, if the input voltage is momentarily connected backwards, or if the 12V is correct but it is connected correctly to an automotive power system where the 12V is actually more like 14V). In the latter case it could cause overheating that would cause a failure much later (perhaps on a hot day).

Personally, in this situation I would leave the TV intact (and under warranty) and use a small (200-300W) 12V-mains voltage inverter (maybe $30 USD equivalent) and switch the input to the inverter to avoid draining the battery from no-load current.

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    \$\begingroup\$ The connector to the far right on the linked PCB picture doesn't look like a 2mm JST, it's some >5mm through-hole connector similar to Molex "single wall" types and sitting next to the AC/DC conversion components. There are JST-like connectors on the board but they aren't for the main supply. \$\endgroup\$
    – Lundin
    Commented Apr 25 at 11:03
  • \$\begingroup\$ You (and @Analog) seem to be referring to the mains input connector. Connecting 12V there is not going to do anything useful, though I suppose it could be jumpered on the PCB to bypass the SMPS. You'd sure want to change the cord to something else lest some hapless person plug it into the mains in the future. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Apr 25 at 12:09
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    \$\begingroup\$ What other 2 pin connector is there? I think the question is perhaps too unclear. \$\endgroup\$
    – Lundin
    Commented Apr 25 at 12:31
  • \$\begingroup\$ Wow, I appreciate the detailed replies. People are selling that TV for 25-60$. I'm not too worried if I mess it up for the sake of this project. I figured 26awg wouldn't be enough, darn it. I'm not well versed on other connectors. I have a 12v monitor I could use the native connector and bypass the power supply. Downer is no sound, which is why I was looking into TV options. I could split the HDMI input with a splitter, that would require external headphones or speakers. That's the backup plan. I have a 1100w inverter, just was trying to keep conversions down \$\endgroup\$
    – Kam Hutchison
    Commented Apr 26 at 13:46
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Am I missing something?

The only thing you're missing is the correct wire. #26 is way too light. I would go with #18, such as "lamp cord", at a minimum. Speaker wire, such as the clear-insulation stuff with one wire tinned for polarity, also would work (only at low voltages, not for mains).

To me that connector looks like a variation of an AMP MTA with 0.156 pin spacing. In your case it is a 3-pin part with the center pin removed. This yields pin spacing wide enough for AC mains connections. Those are typically rated for around 8-10 amps per pin, so it also would work for a DC connection in this application.

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