5 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
75QN90F panel develops growing spots/blemishes; Samsung service calls it user error; speakers crackle
The buyer reports two small spots on the panel at purchase that grew over time and attracted dust; Samsung's service inspected, photographed, then declared it user error and refused to intervene. The same owner also reports intermittent speaker crackling.
What to check. Photograph any panel blemish immediately on delivery and register it before the return window closes. This owner's claim was refused as 'user error' despite the spots growing untouched, so early documentation is the only protection.
QE85QN90FATXTK repeatedly powers on and off due to screen fault, replacement unit shows the same fault
An owner of the 85" QE85QN90FATXTK reports the TV constantly powering on and off since July; the set was replaced under warranty but the replacement exhibited the same fault. Service later claimed no fault and advised using the TV with no HDMI cable connected.
What to check. If you buy a QN90F and it power-cycles, do not accept a single replacement as proof of resolution — this owner's replacement repeated the same fault. Keep the complaint record and push for a refund or different model.
QN90F panel found with dead/stuck pixels at install; Samsung service counts them as not a fault
A QN90F bought from Media Markt had a fixed image defect spotted at install (called 'çapaklanma', burring) plus three dead/stuck pixels found later. The authorized service acknowledged the pixels on its form but stated they are 'not evaluated as a fault', and the complaint record was closed with no report given to the owner.
What to check. Dead/stuck pixels are treated by Samsung service as not a fault, so a panel with a few bad pixels may not qualify for exchange. Check the panel for dead pixels within the first days and know your local consumer-law threshold before relying on warranty.
QN90F powers on but screen stays blank — suspected power-regulation or motherboard fault
An owner describes the set powering on with a completely blank screen and unusual startup behavior, and the repair guidance points to checking the main power input (~19 V) and nearby input MOSFETs on the main board. This is an owner/repairer report, not a manufacturer bulletin.
What to check. A blank screen with the set powered on points to the power-regulation stage or main board rather than the panel. If you see this, a repair shop can measure the main-board rails; decide whether to repair or claim warranty before spending on parts.
QN90F screen dims darker and brighter on its own and shows halo on subtitles/football; possible backlight fault
An owner reports the screen autonomously dimming darker and brighter despite disabling local dimming, contrast and power-saving settings, plus halo on football and subtitle text. Another member notes this could be a backlight fault if it also happens on SDR content.
What to check. If brightness fluctuates on its own even on SDR content with all power-saving and local-dimming settings off, treat it as a possible backlight fault and get it checked under warranty rather than assuming a setting issue.
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.
