3 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
XR-55A80CJ main board failure: no screen, 8 red flashes error code
Owner's repair thread on iFixit for the exact XR-55A80CJ model: TV shows no screen, random power behavior, diagnosed as faulty main board; after a replacement main board the standby LED still flashes the 8-red-flashes error code. This is a hardware failure that leaves the TV unusable and requires main-board replacement or repair (~£187/$190 repair service on the seller listing).
What to check. If an A80C shows no picture with a flashing red standby LED (8 blinks), suspect the main board, not the panel. A main-board repair/replacement is the likely fix and is a significant cost; check warranty coverage before paying.
XR-55A80CJ mainboard repair service symptom list: boot loop, white standby light no picture, HDMI dead, 8-blink
A repair seller's listing for the exact XR-55A80CJ mainboard (A-5026-264-A) lists the failures its service covers: boot-loop cycling, white standby light with no picture, dead/no power, non-working HDMI ports, the 8-blink error code, and pink/green bars. This corroborates the iFixit main-board failure, but as a seller page it is a weaker source.
What to check. The seller's symptom list matches the owner-reported main-board failure, reinforcing that a dead/boot-looping A80C is most likely a main-board problem rather than a panel problem.
XR65A80CJ OLED panel: rectangular dark spots classified as burn-in, warranty denied
Owner thread on Sony's own community for the XR65A80CJ reports two rectangular darker spots visible on grayscale (5-40%), which Sony told the owner were burn-in and not covered by warranty; the owner argues it is a uniformity/panel defect. If the panel is judged burn-in, replacement is out-of-pocket and costly.
What to check. Check the panel for dark rectangular patches on low grayscale early, and confirm what the warranty covers, because Sony may classify the defect as burn-in and decline coverage.
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.
