Sony televisions — particularly CRT-era and early Bravia models — include a hidden service diagnostic mode that displays abbreviated fault codes on-screen. These abbreviations correspond to the blink codes described above and allow a technician to see a log of faults with a count of how many times each has occurred.
To access this mode on many Sony models, press: Display → Channel 5 → Volume Down → Power in sequence. The screen will display a list of fault abbreviations and occurrence counts.
- OCP — Overcurrent Protection
What It Means
OCP stands for Overcurrent Protection. This code appears in the service menu when the TV’s protection circuitry has detected an excessive current draw — meaning more electrical current was flowing through a circuit than is safe — and has shut the TV down to prevent damage.
Common Reasons
A short circuit in one of the TV’s output stages is the most common trigger. Failed transistors or a shorted deflection yoke (in CRT TVs) can cause a sudden spike in current. On LCD models, a shorted LED strip or a failed backlight driver can cause overcurrent conditions in the power supply.
How to Fix It
OCP events require identifying the specific circuit drawing excess current. Use a multimeter to check for short circuits on the most likely boards — the power board, main board, and any output stage boards. In CRT TVs, disconnect the deflection yoke and test whether the OCP clears, which would isolate the fault. On LCD TVs, disconnect the backlight strips one at a time to identify a shorted strip. Replace the faulty component once identified.
- OVP — Overvoltage Protection
What It Means
OVP stands for Overvoltage Protection. This code is logged when the TV’s protection circuits have detected that a voltage rail has exceeded its specified limit, prompting an automatic shutdown to protect components from being damaged by excess voltage.
Common Reasons
A failed voltage regulator that allows a rail to rise uncontrolled is the primary cause. On CRT TVs, a failure in the high voltage regulation circuit — allowing the flyback-generated voltage to exceed limits — is a critical OVP event. On modern TVs, a faulty switch-mode power supply component can allow secondary voltages to drift out of specification.
How to Fix It
Measure the voltage rails on the power board with a multimeter to identify which rail is over-voltage. The service manual for the specific model will list the correct voltage specifications for each rail. Identify and replace the failed voltage regulator, transistor, or feedback component responsible for the uncontrolled voltage rise. Given the risk of component damage from overvoltage, inspect nearby components for collateral damage after the primary fault is repaired.
- V STOP — Vertical Stop / No Vertical Deflection
What It Means
V STOP is the service mode abbreviation for the vertical deflection stop fault, corresponding to the 4-blink code on CRT-era Sony televisions. It indicates that the vertical scanning circuit has failed, causing the picture to collapse to a single horizontal line across the centre of the screen, after which the TV mutes the video.
Common Reasons
The vertical output IC — IC1509 in many Sony models — is the most common point of failure. Supporting components Q1505 and related passive components in the vertical output stage also fail over time. Overheating of the deflection board or heat damage to solder joints can cause intermittent V STOP faults that become permanent.
How to Fix It
Replace the vertical output IC as the first step. Check the datasheet for IC1509 or the equivalent part number for your model to source a compatible replacement. Inspect and test Q1505 and surrounding resistors and capacitors. Reflow or replace cold solder joints on the deflection board. After replacement, verify the vertical size and linearity settings in the service menu are within specification.
- AKB — Automatic Kinescope Bias Circuit Error
What It Means
AKB in the service menu refers to a fault in the Automatic Kinescope Bias circuit, corresponding to the 5-blink code on CRT Sony televisions. The AKB circuit continuously measures the black level output of each electron gun and adjusts bias voltages to maintain consistent, accurate black levels across the picture.
Common Reasons
Ageing CRT electron guns that no longer produce consistent emissions can throw the AKB circuit out of its operating range. Faulty components in the video output stage — particularly transistors Q705, Q732, Q761, Q218, Q219, and Q220 — can corrupt the AKB feedback signal. IK (Inverse Kinescope) blanking conditions can also mask or mimic AKB faults.
How to Fix It
Test the CRT with a CRT analyser to evaluate the condition of the electron guns. If gun emissions are within tolerance, focus the investigation on the listed video output transistors. Replace any transistors that test as shorted or out of specification. After repair, recalibrate the screen (G2) voltage and white balance settings in the service menu to restore correct picture performance.
- PROTECT MODE — General Protection Shutdown
What It Means
PROTECT MODE is a general fault designation that appears when the TV’s protection circuits have intervened but the specific fault cannot be narrowed to a single abbreviation. It indicates that some aspect of the TV’s operation — voltage, current, temperature, or a specific circuit — has gone outside safe limits and the TV has shut down as a precaution.
Common Reasons
PROTECT MODE can be triggered by any of the conditions described in the specific fault codes above: overvoltage, overcurrent, overtemperature, audio amplifier faults, or deflection circuit failures. It is also triggered when the TV detects a more general hardware anomaly that does not map to a specific named fault. On newer Bravia models, software faults can occasionally cause the TV to enter a software-based protect mode.
How to Fix It
Begin with a full power reset. Access the service menu (using the key combination described above) to check whether a more specific fault code — OCP, OVP, V STOP, AKB, or other — has been logged alongside the PROTECT MODE entry. Use the specific code to guide your troubleshooting. If no specific code accompanies the PROTECT MODE entry, systematic testing of all boards and voltage rails will be required to identify the root cause. A service technician with access to the TV’s service manual is best placed to diagnose a non-specific PROTECT MODE fault.
This guide covers the full range of Sony television error codes across all major platforms and model generations. For model-specific service manuals and the most current firmware downloads, visit sony.com/support. When in doubt, always consult a qualified repair technician — particularly for faults involving high voltage circuits.