3 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
Q60B main board failure quoted at €249 repair by Samsung service
An owner review on Samsung's Italian product page for the QE50Q60BAUXZT.
What to check. An owner was quoted €249 by Samsung service to replace the main board on a Q60B bought in 2022, a cost close to the price of a new budget TV. This shows the main board is a costly, common failure point that can make repair uneconomic.
Q60B series bootloop with black screen reported as serial panel/logic-board defect (QE50Q60BAU)
This is a consumer-association complaint board (Altroconsumo) with multiple independent QE50Q60BAU complaints describing the same failure.
What to check. Multiple owners report the TV suddenly entering an infinite reboot loop with a black screen, often just after the legal warranty ends (~2-3 years), and Samsung refusing free repair and quoting a fully owner-paid intervention. A buyer should treat this series as carrying a real risk of a catastrophic, out-of-warranty failure and should consider extended warranty or a different model.
Horizontal black lines appear on Q60B LCD panel after ~2 years
These are owner reviews on Samsung's own Italian product page for the QE50Q60BAUXZT.
What to check. Several owners report horizontal black lines appearing on the panel after roughly two years, after the warranty has lapsed, leaving the owner to pay for a panel that is usually uneconomic to replace. This is a display-panel defect specific to the series.
These reports come from the pages linked under each item: owner forums, repair guides and workshops. They are not a diagnosis of any one unit, and a careful check of the one you are buying still applies.
Text from the Kriko Televisions catalog, version 0.1.1, under the CC-BY-SA-4.0 license.