Getting your Samsung phone's broken screen repaired at an unauthorized third-party shop unfortunately can void your device's warranty. Samsung's warranty terms state that repairs must be done at authorized Samsung service centers to maintain warranty coverage.

However, there are a few things to keep in mind:

• If there is no physical damage and just the display is cracked, some repair shops may be able to replace just the screen without voiding the warranty. Check with the shop beforehand.
• For more complex repairs involving multiple components, the warranty is more likely to be voided.
• Using genuine OEM parts instead of third-party replacements has a lower chance of voiding the warranty. Again, check with the repair shop first.
• Warranty coverage varies by region, so check Samsung's policy for your country. There may be exceptions.
• Repairing at a Samsung authorized service center is the safest option to avoid voiding your warranty. However, it's often more expensive.

So in summary, non-Samsung repairs do carry a risk of voiding the warranty, but your specific situation may differ. Check regional policies and repair scope to minimize that risk if retaining the warranty is important to you. Official Samsung repairs are recommended to fully keep warranty intact. For Samsung phone screen repair service in Sydney, Mobile Repair Doctor is better option.