Mac USB

[Sheha]

Hi.
I’m using a 2015 mac 27.

I’ve tried recently to reinstall catalina after erasing the disk. Now all of the USB ports don’t work.

I’ve tried plugging my phone to see if power comes out. When the machines switches on power from USB appears for a second and no more after that.

There’s no way for me to connect the keyboard and mouse to do so called SMC reset.

Your help is much appropriated

 

[TonyAguila]

Hi.
I’m using a 2015 mac 27.

I’ve tried recently to reinstall catalina after erasing the disk. Now all of the USB ports don’t work.

I’ve tried plugging my phone to see if power comes out. When the machines switches on power from USB appears for a second and no more after that.

There’s no way for me to connect the keyboard and mouse to do so called SMC reset.

Your help is much appropriated

You don’t need the keyboard or mouse to reset SMC. With the iMac powered down, press and hold the power button for about 10 seconds. Release and wait a few seconds, then press again to start the computer. If this does not fix the problem, shut down again. Unplug the power cord from the back of the iMac. Wait about 15 seconds to plug it back in and press the power button to restart.

If this does not fix the problem, you may have to bring it in for service since you won’t be able to do any more diagnostics without the keyboard, unless you have a Bluetooth keyboard, in which case you may be able to run the hardware test (assuming the BT keyboard successfully connects on startup) by holding down the “D” key. And if the Bluetooth keyboard truly works, you can even do a parameter RAM (PRAM) reset (⌘-⌥-P-R).

If the above was a success, you can then test your USB ports.