Second Hand Switch Charges on dock and TV recognises signal but doesn't display on TV (Solid Green Light)

Hi All,

I was wondering if this is a USB C port Issue on the switch or Video / Audio IC (PI3USB.)
Switch charges fine in docked and tablet mode, but when docked the TV picks up a signal but displays nothing, I have stripped the dock right down to the bare connector and if I flip the USB C Male 180 degrees it will then display on the TV.

I have tried 4 TVs / monitors, 3 HDMI cables and a different dock with the same results.

The only thing I haven’t tried is another PSU.


I also checked and either way I plug the USB C cable from my PC to my switch it does detect it.


So after a couple hours and getting no where, I thought lets look at the inside of the port. Looks fine no bent pins, to be on the safe side I thought I would just scrape against them with a plastic tool in case there was any stubborn grime on the pins as I couldn’t see any and there must of been as it now works in docked mode.

When I get home will crack out the IPA and give it a proper clean.

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Thank you for posting this solution. I’ve fixed a number of Switches just by cleaning the USB C port.

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Update -

Turns out I am out of IPA and this COVID-19 has driven prices up in the UK thanks to people making their own hand gel.

I gave it a clean with a stiff bristle brush and it now shows signal every time it is docked.

It is still a little iffy if it gets knocked it may stop showing an image, I think this may also need a new USB C port as I am assuming it is a little loose. Unfortunately I am not as confident in replacing it as I am with other SMD soldering, last time whilst I able to change out the port I tore up one trace and as I don’t have a magnifying scope set up I found it hard to run traces.

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Good information friend


I’m a bit confused. I have two Switches with problems displaying on a TV.

To verify that all USB C port pins on both Switches are proper soldered and make good contact, I made the same as PIXeL_92 and stripped a good working dock, plugged in in the switches and checked between the filters, testpoints and the end of the ribbon cabel.

The pin I miss from the USB C Specs is the CC2 signal.
Is this pin (CC2) present on a properly working Switch?

USB C Dock Kabel

Welcome Calvin.

You’re in the right place for help. The CC pins are critical for this to work properly as they help the M92 determine the orientation of the connector, and signals to the PIUSB to multiplex the video across the connector via the right pins. If one of the CC lines is compromised, then you get a situation where video will only work one way, and charging will only work one way. If both are dead, then you will get no video.

The CC lines are the most vulnerable in the USB Type-C standard as misplaced pins can zap all sorts of things. In my experience, I’ve seen an M92 largely working except that its CC detection circuits were screwed up. A quick replace of the chip and all was working again. The other thing I’d recommend you check is whether there is an ESD protection device fitted (on the underside of the board, near the USB Type-C connector). It’s close to two test points which will be your CC lines. I’ve seen these things get zapped and die resulting in orientation issues and an inability to display on the TV. Luckily it was not on subsequent revisions of the board, so it can be temporarily removed to test the theory.

Good luck!


I found the cause of the issue at the first Switch. It was a poor connection from the SBU1 signal at Pin 21 on the PI3USB IC. After adding a bit flux and a bit new solder to the pin, the SUB1 Signal shows the expected Diode measurring value (~.745 V) at the end of the ribbon cable. After reassembling, the first switch is working fine again. :slight_smile:

If I’m right: There is no CC2 line at the ribbon cabel to the dock. Which I expected earlier as missing.

Now I m trying to figure out what is causing the second Switch to show no signals on TV.

The second Switch is now also working fine. :smile:

I couldn t find a missing or poor connection at the PI3USB pins. All pins are shown the expected diode mode meassuring values and the lines to the USB C were all tested fine.

My plan was to replace the PI3USB. But before that I gave a reflow a try. And after reflowing the PI3USB IC the Switch is displaying on the TV again. Seems to have been also a poor solder connection at one of the pins.