Xbox Series X Console Won't Turn On - Broken Nexus Connector on Mainboard

[gabri2211]

Hello everyone,
Inside the console there is a small circuit board (see photo) that contains the main power switch, the one on the front.
This circuit board connects to a 10-pin flat cable called NEXUS that terminates on the motherboard.
This NEXUS connector broke.

Can anyone tell me, while waiting for a replacement, if it's possible to turn on the Xbox by disconnecting this circuit board and making some modifications (like adding a small power button) on the motherboard?

The Xbox has a power supply that provides 12 volts on all outputs, so the power supply is fine.

Without this circuit board connected, can you tell me if I should receive any visual or audible indications from the console?

Is it possible that without this board there's no alternative method to turn on the console?

Thanks to anyone who can help.

[Green Probe]

If you have a controller that is already paired to the xbox console, then holding the xbox button on the controller should power on the xbox console. Plugging in a controller with a USB cable and holding the Xbox button may work. The Xbox should make a chime sound when powered on. The fan should also spin.

You should be able to short pin 4 to ground to simulate a power button. There are also debug pads that would be handy for installing a button
This is a page that describes bypassing the Nexus board entirely, and should have just what you need.
https://www.retrosix.wiki/xbox-series-x-daughterboard#3XwIN

[gabri2211]

hello Green Probe. Thanks for your answer
I've already done all the tests you mentioned. The controller is already paired, and it's always worked with the Xbox. I've already checked the site you linked, but it provides incorrect information; it could even provide solutions that damage the Xbox. The instructions say that the 170 resistor is connected to pin 4, but that's not true. At least on my Xbox, there's no connection between pin 4 of the Nexus connector. I tried it with my digital tester! Connecting that point to ground could damage the console. If I test pin 6 on the motherboard, it's not connected to ground as they indicated. I'm not entirely sure they're saying anything useful, but I think they're misleading.
I connected pin 4 of the Nexus to ground, but the Xbox doesn't turn on or make any sound. If you've actually done these tests yourself, please confirm how you did it. Thanks.

[Unspun01]

If your nexus connector is damaged, remove the flex ribbon cable from the connector and try inserting a disc into the drive. The XBOX will turn on automatically. Then you can pair or use a USB connected controller as normal. If a disc is already in the drive, use an unfolded paper clip or other small diameter rigid wire/item to manually eject the disc through the small hole on the side of the disc drive and re-insert the disc and try again.

If the XBOX is otherwise working condition, this will turn on the XBOX.

I had an XBOX series X with a damaged nexus connector on mainboard, and XBOX would not do anything until the flex ribbon cable was removed. Not sure why, but maybe something inside the connector was shorting to ground. These are very delicate and easy to damage. A damaged connector will often make a console appear completely dead.

Also, if you have no luck, use good light and magnifying lens to see if any pins inside the damaged nexus connector are bent or touching each other or the grounded shell of the nexus connecter internally and see if you can bend away from the contact point.

[gabri2211]

Hello Unspun01
Thank you so much for your comment.
I think I'll check this out as soon as possible.
from what you're telling me, it should help me figure out if the Xbox died due to some other problem, or if the switch plate (or flat cable) is the culprit. In that regard, I just ordered the ribbon cable with the plate and connector.

Maybe I'll try to replace it myself, or better yet, have someone who repairs cell phones do it. Unfortunately, no one in my city repairs game consoles.

When I reassembled the Xbox, I forgot to connect that small 12V two-pole connector, and I finally turned on the console, thinking everything was fine. (The connector is the one that connects from the power supply to the motherboard, so it's not visible after inserting the aluminum casing.)

In your opinion, could turning on the Xbox without connecting that connector, have caused the console to malfunction?


Your suggestion comes like a ray of sunshine in the darkness. 🙂🙂🙂
Thanks again. 😊😊😊

[Unspun01]

@gabri2211:

If you did not connect the 12V two-pole connector between the power supply and the motherboard, then the XBOX would not turn on for sure. The power supply provided 12V, 5V, 3.3V as well as ps-on signals, etc. Other voltages are generated on the motherboard from the 12V, 5V or 3.3V.

Without the 2-pole connector attached, you won't really damage anything but If the 12V is missing, so are the lower voltages generated from that 12V power rail.

Many times, the flex ribbon cable is also damaged when the nexus connector is damaged and I do not recommend re-using it. Sometimes the ribbon pins are damaged or bent or broken and can cause other shorts.

Because the flex ribbon is secured to the case with adhesive, the separate power board with the power button is usually ok (doesn't really get pulled on). Usually, it is only the nexus connector on the mainboard which gets damaged.

When replacing a broken/damaged nexus connector, it is helpful to flood the solder pins of the old one with fresh flux and lead solder (lower melting point) and remove it slowly with the heat from a direct contact soldering iron.

When installing a new nexus connector, it is difficult to solder directly and even using a hot air re-work station I only ever re-install a new connector by heating from the bottom with hot air so I do not melt any nearby plastic connectors on the top side by the nexus connector.

[gabri2211]

Hello Unspun01
Thanks again for these tips!!!
I bought a cheap air soldering iron some time ago and have already used it with less than spectacular results, but... I got by.
I've had to put these Xbox tests on hold for family reasons, but I plan to start testing again soon.
In your opinion, it's definitely better to use the air soldering iron by pointing it at the connector's circuit board from underneath.
I'm not sure if I need to physically disconnect the motherboard containing it first, or if I can risk heating it directly from underneath.
I also have the "Koptan" tape. I had ordered it as "Kapton," but the Chinese guys sent me this. There's no point sending it back to pay for shipping to China... I hope it's at least as temperature-resistant as the "kapton" one, which looks very similar anyway, the yellow one made specifically for heat protection.
Do you think I could protect the surrounding areas with tape and solder from above, or is it better to place the air soldering iron from below?
What temperature would be best? 450 degrees or less?
my solder is 60 lead 40 tin, will it be okay?
However, before attempting this connector replacement, I will practice very well by doing it on other connectors present in the motherboards of old laptops that I have found elsewhere.
Thanks again if you'd like to reply.

[Unspun01]

Hi -
The nexus connector replacement needs the affected motherboard to be completely removed from the xbox. This required near complete disassembly of the xbox boards from each other and from the aluminum frrame(make note of where all the screws go since there are a few different kinds and lengths).

Kapton tape is useful in certain repairs, but will not be useful here. to protect nearby plastic connectors on topside near nexus connector, I recommend 2 layers of common aluminum foil. Cut and bend it to fit closely around the connectors but NOT TOUCHING the connectors. the two layers will help dissipate heat from one layer to the next and also prevent damage to the plastic. You can use kapton tape to secure the aluminum foil in place. Works well if you are careful. And be careful, because even though the foil is a good shield, it can knock small surface mount components around when hot if you are not careful.

But note that you still need to apply heat from the bottom of the board. Do not try to remove, or re-install the nexus connector with hot air applied from the top. Too much heat is needed and not even aluminum foil will protect the plastic parts from melting and getting damaged.

NEXUS REMOVAL:
Use direct heat soldering iron from top (and hot air from bottom).

As I stated before, use FLUX and good leaded solder to flood the pins of the damaged nexus connector with excess solder. Yes you will short all the pins, but this is ok for now. The excess leaded solder on all the pins will get fully molten with heat and stay molten during removal. Use only gentle pressure to wiggle during removal and do NOT pull anything too hard or you will risk pulling traces.

The nexus connector may come apart into pieces and this is fine since it is damaged anyway. Just be careful and take your time. Once it comes off, you can use more flux and leaded solder to add new solder onto all of the pins and the grounding pads that support the connector. The solder should look shiny and not dull. again use lots of flux. flux helps the solder flow nicely and is imperative to re-installing the new connector.

RE-INSTALL NEXUS:
Support the board in a way that it will not move and you can access the underside with hot air wand with plenty of room and not bump anything.

Add fresh flux to top side of nexus connector area (after wiping clean any old residues or dirt). With the fresh solder already in place, and plenty of fresh flux, heat applied consistently from bottom will re-melt the solder and surface tension of the liquid flux will pull the nexus connector into place. If successful, all of the pins will reflow and connections will be good. I only use a direct heat soldering iron to add a bit more solder to the ground pads on either side of the connector after the connector is re-soldered.

Set your hot air wand to med/max air flow. Set temperature to 400C. Any less temperature and it will take too long to heat and you will be there forever. If you use too much heat, you can damage the circuit board by de-laminating it and other nearby components will not tolerate such heat for long.

Sorry for long replies, but this is a delicate repair and I think more guidance is better than less guidance.

[gabri2211]

Hello Unspun01

Thanks again for continuing to give me advice. Don't worry about lengthy explanations, but rather, I welcome any explanations you can give, even better if they're long.
A few days ago, and I think for a long time to come, my wife broke her wrist.
With her arm in a cast, she won't be able to do any work around the house.
So the time I dedicate primarily to her and my son will prevent me from doing this repair.
Patience, I'll wait for better times to do it calmly.
What you explained makes me increasingly afraid to touch the Nexus, but I'll try to practice very well with other soldering jobs on scrapped devices. I don't have professional equipment; the soldering iron is very long and the tip isn't small. It's very good for discrete components, but it's very large for SMDs, even though I can often work miracles with them.
If you hadn't explained what you said, I would definitely have done things wrong.
A few months ago, I desoldered some LEDs with an air soldering iron from above, and I realized it was the wrong way to do it.
Unfortunately, I also have problems with my hands, which sometimes shake, especially when I can't work very steadily (a long soldering iron forces unstable positions).
Okay, I hope to let you know how it went soon.
Thanks again... as you can see, I also take a long time to write.