Boards and faults guide: standby, power supply and mainboard repairs

Most TV repairs begin with the same question: where in the chain from the mains socket to the panel does it stop? These guides cover the board-level side of the work, from a dead set with no standby light to faults that repeat on a particular mainboard family.

The articles are written for repair technicians. They stick to checks that are common practice or that come from the FW Tool reference data, and anything we could not confirm is marked UNVERIFIED. The mains side of a TV is dangerous, so read the safety notes before you open a set.

• Checking electrolytic capacitors by ESR: why and how to read the result
  Why capacitance alone does not show a bad capacitor and how to use ESR in repairs.
• TV does not turn on: no standby light, step-by-step checks
  A safe, ordered way to diagnose a TV with no standby LED and no reaction: mains, fuse, bulk capacitor, standby rail, feedback loop.
• Typical faults by mainboard family: how to use the faults database
  How to read the FW Tool faults-by-mainboard database, what confirmed and single-source mean, and examples from the sample data.

Where to start

If the set shows no sign of life, begin with TV does not turn on: no standby light and work through the power supply in order. Suspicious capacitors found along the way can be judged properly with checking electrolytic capacitors by ESR. When the set starts but misbehaves (boot loop, no picture, no backlight), read typical faults by mainboard family to see whether your board is already described. For the rest of the program, see the features page.