Lenovo Yoga 710 15ISK, 80U00002US battery cable wire broken.

[emeskay]

We have an Lenovo Yoga 710 15ISK that we use as a secondary laptop. To cut a long story short, around May 2023, while traveling, I connected the laptop into an electrical outlet that was already switched on. Something made a "pfft" sound and the laptop refused to turn on after that. After getting back home, I gave the the laptop for repair to an informal repair person. He replaced the adapter and an internal motherboard part, but after he returned it I noticed that the LCD did not look normal. Essentially, every alternate horizontal line on the screen had gone missing. The laptop was still usable but text was a little difficult to read.

Since I wasn't sure if it was the LCD screen itself, I initially replaced the display cable connector (not an easy job since the screen had to be removed, but luckily there are a number of YouTube videos that really helped). However that did not change anything. Now before changing the display connector, I had to disconnect the battery. This turned out to be fiendishly difficult since the connector was impossibly tight. As a result, I managed to break one of the wires - the black one (which for some reason, the repair person had soldered to the battery connector). See the photo attachment to see the broken wire.

The laptop still works without the black wire but it needs to be plugged in all the time. I also managed (after much difficulty) to find the correct LCD screen for this 1080P touch screen model and replace that. So now the laptop is fine except for the battery connection.

My questions:
1. Is there an easy way to replace the cable?
2. Do I have to give it to a technician (as I have no soldering skills at all)
3. Would it be best to buy a new battery (Note: Battery was replaced once in 2021 after the old battery swelled up). I assume that the black wire has something to do with charging the battery and it has now not been charged since May 2023.

It is a perfectly good laptop and since I have already spent some money on it, I would rather be able to simply replace the cable.

[mcplslg123]

Do you have a multimeter and soldering iron/flux?
The black wire is for Ground and current wont flow unless Ground is connected.
You can easily solder that black wire to any point which is GND on the motherboard.

[emeskay]

I could get an inexpensive soldering kit from Amazon. I would also have to invest in a multi-meter. Should be interesting since I have never touched a soldering iron before😀. Lenovo has a few authorized service centers in Bangalore. If they too are going to essentially do the same thing (that is solder it rather than replace the cable or the plug), then I might as well give it a try myself. Any thoughts? Thank You.

[piernov]

I'm not sure it makes a lot of sense for somebody to spend time fixing the existing battery. You can see that the data line wires are coming out of the plug and that one red wire (carrying the current from the battery) is pinched. So a proper repair goes beyond just a dodgy fix of soldering the ground wire.
It would involve either fixing the existing cable (if it's long enough, by cutting and recrimping wires and replacing the housing) or replacing the entire cable (desoldering from the BMS board and soldering one from another dead battery for example). It's not that much work if you have the materials and experience, but still if you can find a good battery I think it makes more sense to just replace it. You can always ask a third-party repair shop what they can do for you. Lenovo will just replace the battery.

[emeskay]

I contacted an authorized Lenovo repair center here and they have asked to see the laptop to check if the connector repair is feasible. I'll be taking it to them tomorrow and I'll post an update here. Thank you.

[mcplslg123]

Replacing the battery will be perhaps cheaper then the bill provided by so called Authorised Service centre. Moreover,even if you decline the repair,they will charge you inspection charges.

[emeskay]

I have got the laptop back from the service center. They were able to successfully repair the cable. I have attached a photo of the repaired cable. Note that they seem to have grounded the black wire in a different way.

Nevertheless, the battery is charging now and the laptop is pretty much normal. While the service charges were higher than what I had expected, it was about 50% of what I would have paid for an new battery. So not all that bad. Also they gave the hardware a general checkup and according to them there are no serious problems but the mic is not working. I'll have to check that out as the mic hasn't been used for a long time. Also for sometime the bluetooth audio has been having a stutter. I resolved that by uninstalling some spurious bluetooth drivers. That more or less solved the problem but there is still a very slight stutter which is noticeable when listening to music. I'm attributing this to latency problems due to software/OS issues. Hopefully that will go away if I do a clean install of Windows 10.

In any case, thank you very much mcplslg123 and piernov for your help.