Change 85W magsafe broken cable with new one, but detected as 60W

The chip which communicates with the mac's SMC through the onewire circuit is responsible for storing the serial number (which your mac derives the AC adapter wattage from) is located in the head of the charger (the part with the orange/green LED). The mac doesn't transfer any information between itself and the AC adapter block, only power.

"The magsafe connector has a small chip inside which is programmed with the magsafe psu serial number and other data including the power rating. If you put a cable from a 60W supply on to an 85w supply it will report it as a 60W supply with the serial number from the old unit.

eBay/Ali express replacement cables carry the same problem and have all 0000 serial numbers. same as aftermarket chargers."

"anyone know’s a good source for 85W magsafe 1 cables?

The ones I got off ali and ebay, all identify as 60W.

Since there are knockoff chargers that report as being 85W, I guess that there are cables with the right chip inside the magsafe connector. And the people responding here that the cable has nothing to do with this, you don’t know what you are talking about. The chip where the smc communicates with is located on a small pcb (where the pin’s are on), inside the magsafe connector."

"Jo Lodewyckx You are absolutely correct and spot on!!! I have been going blue in the face trying to explain this very dilema to sellers of magsafe cord all telling me it is compatible as they dont even know themselves, there was one or two selling 85W magsafes on Ali who did know about the existance and would only ship them to you if you specfied that you want a 85W cable, but they have long gone and I have given up emailing aliexpress sellers, ebay sellers all selling 60W thinking its compatible.

I can confirm they do exist as I have purchased a lot of the them in the past for my refurbished macbook business, wish I got more if I had known how hard they are to find.

60W does work with macbooks that require 85W chargers, however, if your battery is dead or no battery, the macbook will not start up, if you have a battery, you would need to wait until it has charged up a little for the macbook to power on and then slowley continue charging with the 60W, if you have no battery or battery dies completely, your macbook will never start on a 60W detected charger even tho it may be a 85W unit with a 60W cable.

Hope thats cleared it up for a few folks!!! (has anyone found a good source?)"

"All the cables are the same. There is no cable that is specific to Wattage.

Are you sure it's an 85 Watt charger ?"

"Hi Dan, I was one of the first subscribers to L . Rossmann many years ago, I had a small workshop with all the mid to top spec gear including a InfraRed Bga machine, long gave up that business as UK costumers specially in east london do not want to pay a great deal for repairs of thier macbook, and no way near what Louis charges.

I do not repair knock off chargers as they are dangerous and I have found many genuine looking chargers that are fake inside.

I can tell you that the cords genuine apple or not, they still work correctly with Genuine macbook chargers if you know how to replace them well as I do. I do not cut open the chargers, only prise them with a special tool which keeps a Lip intact around the edges which allows you to be able to glue them back together with very strong Glue. I have 3 chargers in my home all in use, one from 10 years ago, another from around 7 years and another which is mag 2 few years ago, all working perfectly as they should.

Few volts are passed through to the macbook logic board with no green light, which enables the one wire circuit to then coms back to charger that all is well and allow 18v to pass (green light).

I test all the cables I get via my bench supply & logic board that I purposfully disabled one wire to emitate a fault, not yet found a cable that has not worked correclty apart from sellers stating its 85W when its 60W in which case I only use it for 60W chargers. (use my bench supply and a working macbook to check what it detects before soldering it into a charger)"