Samsung OLED S90C / S90D (2023-2024): quick sheet

Covers: Samsung 4K OLED S90C (2023, e.g. QN65S90CAFXZA) and S90D (2024, e.g. QN65S90DAFXZA; 42, 48, 55, 65, 77, 83 in). Panel source varies: the 83 in S90C and the 42/48/83 in S90D are reported to use LG Display WOLED; 55/65/77 in S90D may use either Samsung QD-OLED or LG WOLED ('panel lottery').

Single sourceBrands: Samsung7 components

Samsung's mid OLED line. There is no backlight: each pixel makes its own light, so the repair blocks are power board, main board, panel timing electronics and the OLED panel itself. Because two different panel types ship under one model name, compare the exact model suffix and panel label before ordering any panel-side part.

Safety first

Unplug and wait before opening.
OLED panels are thin and crack if flexed; support the whole surface and use two people.
Power-board live tests are caution work.

How it works

The power board makes standby and panel rails; the main board (Tizen, HDMI) sends video to the panel's timing electronics, which drive the OLED panel directly. A dead power board means no standby; a failed panel side gives lines, blocks or a dark screen with sound.

OLED sets run panel-care routines (Samsung Pixel Refresh) when switched off with the remote. Unplugging right after viewing can skip them.

Burn-in and image retention are panel wear, not board faults. Panel replacement normally costs close to a new set.

Components & tests

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Official manufacturer documentation

Always confirm values against the tech sheet for the exact model.

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work. © 2026 OnCall Tech. Original content; not a reproduction of any manufacturer document.Generic part photos (not of this brand): Main electrical panel beside a subpanel with its cover removed by Gvolk, CC BY-SA 3.0

Diagnostic guides for this appliance

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