An electronic device not switching on can be the result of many things. Most commonly there is a fault with the mainboard or the battery. We can diagnose a range of issues and replace only what's needed to be.
Many touchscreens won't work if the device has been a victim to a heavy fall or if the device has previously been 'repaired' and a genuine screen wasn't used in the replacement.
That was a bit silly, wasn't it? Some believe putting the device in a bag of rice will solve all your problems. But this isn't true and sometimes the damage has already been done.
Most repairs are done within 15 to 45 minutes. Logic-board repair may take longer time depending on the issue.