Samsung 75" QLED - Complete Power Supply Rebuild (October 2025)

Samsung QN75Q90C came in with power supply failure. This is a premium QLED TV, so the customer wanted it repaired instead of replaced.

Premium QLED TVs have more complex power supplies, but the repair process is the same: replace the failed capacitors.

Initial Diagnosis

Opened it up. Power supply board had several visibly bulging capacitors. The tops were domed instead of flat.

This is classic capacitor failure.

Planning the Repair

Rather than replace capacitors one at a time, I decided to do a complete power supply rebuild. This ensures maximum reliability.

The Repair

Replaced ALL electrolytic capacitors on the power supply board: - 8x 1000µF 10V (replaced with 1000µF 16V 105°C) - 6x 470µF 25V (replaced with 470µF 35V 105°C) - 4x 220µF 25V (replaced with 220µF 35V 105°C)

Used premium Nichicon capacitors for all replacements. They're more expensive but last much longer.

Testing and Verification

Powered it up. All voltage rails came up correctly. Let it run for 48 hours under load. Rock solid.

Checked the picture quality. Perfect. QLED brightness and color accuracy were excellent.

Why This Matters

Premium QLED TVs are expensive. Repairing them instead of replacing them makes financial sense.

A complete power supply rebuild costs $150-200. A new TV costs $2000+.

Cost Analysis

Complete power supply rebuild: $180 Labor: 2 hours Total: $280

New Samsung 75" QLED TV: $2000+

The customer saved $1720+ by repairing instead of replacing.

Prevention Strategy

Use a surge protector. Power surges can damage capacitors. A good surge protector costs $30 and can save you thousands.

Also, consider preventive maintenance. Replace capacitors every 5-7 years to avoid sudden failure.