Vertical or horizontal lines on TV screen
Vertical or horizontal lines on a TV screen are one of the most common and also one of the trickiest faults in modern LCD and OLED televisions. A solid colour band usually points to a T-CON board failure; a rapidly shifting "rainbow" — to an LVDS connection issue; a permanent vertical line with a black band beside it — to COF tape delamination from the panel glass; a single isolated line — to a panel pixel-column failure, which in most cases is not economical to repair.
The root cause can be several different things: a faulty T-CON board, a loose or damaged LVDS ribbon cable between the mainboard and T-CON, a failed COF (chip-on-film) source driver bonded to the edge of the panel glass, degradation of the row driver ASIC on the panel, or genuine failure of the panel itself. One specific case worth flagging is the well-known FFC cable defect on 2018–2021 LG OLED sets — a serial issue where the T-CON FFC ribbon loses contact over time and produces characteristic vertical lines. We will be honest up front: T-CON board repair, LVDS ribbon replacement and LG OLED FFC ribbon restoration are genuinely repairable and often economically sensible. Row driver ASIC failures on the panel and COF delamination at the edge of the glass, on the other hand, are in most cases not economically viable — and you will be the first to hear an honest verdict rather than an expensive fantasy.
Likely causes
- Faulty T-CON board — The timing controller board loses sync or part of its outputs — regular vertical/horizontal lines, double images or evenly tinted fields appear. Often repairable by reworking a chip or replacing the whole T-CON.
- Loose or damaged LVDS ribbon cable — The ribbon between mainboard and T-CON oxidises or sits poorly in the connector — lines can shift or appear as a rapidly changing "rainbow". One of the cheapest fixes.
- LG OLED FFC ribbon defect (2018–2021 models) — A well-known serial issue on LG OLED B/C/E sets — the T-CON FFC ribbon connection loses contact over time and produces persistent vertical lines. In most cases repairable by reworking or replacing the ribbon, without swapping the whole T-CON module.
- COF (chip-on-film) source driver failure — The driver chip on a ribbon bonded directly to the edge of the panel glass loses contact or burns out — typically a permanent vertical line with a black band beside it appears. Proper COF rebonding needs factory equipment, and we do not take this on.
- Panel row driver ASIC degradation — Typical on 4–6 year old OLEDs and premium LCDs — individual rows or columns drop out, or a single isolated line appears. This is a panel defect, not an electronics one, and is not economical to repair.
- Panel bonding failure from heat and age — The bond between panel glass and its ribbons delaminates from thermal stress — a horizontal line can come and go when the chassis is gently flexed.
- Firmware corruption — Rare but possible — especially on some Samsung Tizen sets after a failed update. Solved by a proper firmware reflash.
Try this first
- Switch to a different input (HDMI1 → HDMI2, aerial, USB). If the lines remain across every input, the fault is in the panel or T-CON, not the source.
- Unplug the TV from the wall for 2–3 minutes and power it back on — a simple cold reset sometimes clears firmware glitches.
- Check whether the lines change when you gently touch the chassis next to the screen (NOT the screen itself) — if they do, a loose ribbon or bonding issue is likely.
- See whether the lines are visible in the TV menu (yes — hardware fault) or only on certain content (then it may be a source problem).
When to bring it in
Important: DO NOT press on the panel glass. A single fingertip push can turn a repairable fault into a non-repairable one — the internal LCD layers are extremely fragile. Also DO NOT open the TV yourself: the T-CON and mainboard carry high-voltage capacitors that stay charged for hours after unplugging. Bring the TV to us and we will tell you exactly whether it is a T-CON issue (repairable), an LVDS ribbon (cheap), an LG OLED FFC ribbon (repairable), a COF fault (new panel needed) or a panel ASIC failure (usually not economical). We agree the quote before any work begins.
Fast on-site diagnostics. Repair warranty: 3 months.
Brands we repair
FAQ
Why customers choose SATER
- TV repair — from CRT to the latest Smart TVs. We repair televisions of every generation in Riga — from tube sets to OLED and QLED.
- LED backlight diagnostics on a professional test rig. We pinpoint the faulty LED strip without replacing the entire panel.
- Samsung, LG, Sony parts in stock. Power boards, T-Con boards, LED drivers — key components always on the shelf.
- 30+ years of experience. The service centre has been operating since 1993.
- We serve all of Latvia. Electronics service centre in Riga — we accept devices from anywhere in the country.