Older Sony televisions using CRT (cathode ray tube) technology also employed a self-diagnostic blink system, though the codes and the components they refer to differ significantly from modern flat-screen models. These codes are relevant to Sony Trinitron and Wega CRT TVs.
- 2 Blinks — D Board Failure
What It Means
On legacy Sony CRT televisions, two blinks indicate a failure on the D Board, which serves as the main power supply and video processing board. The D Board is central to the TV’s operation, handling both power distribution and video signal processing.
Common Reasons
The D Board can fail due to blown fuses, failed capacitors, or damaged transistors. Power surges are a common trigger. Short circuits on connected components can also overload the D Board and cause it to fail.
How to Fix It
In most cases, D Board failure requires board-level repair or a complete replacement with a compatible unit. Check fuses on the board first, as these are the simplest component to replace. If capacitors appear swollen or leaking, a recapping job (replacing all electrolytic capacitors) can restore the board to working order. Given the age of most CRT TVs where this code applies, sourcing replacement boards may require specialist suppliers or online marketplaces.
- 3 Blinks — G Board Failure (IC501/IC5002)
What It Means
Three blinks on a Sony CRT TV point to a fault on the G Board, specifically involving integrated circuits IC501 and IC5002. The G Board manages deflection and scanning circuits. When these ICs fail, the TV enters standby mode and will not produce a picture.
Common Reasons
IC501 and IC5002 are susceptible to failure due to heat stress over long operating periods. Dry solder joints under these chips — a common issue in ageing circuit boards — can cause intermittent or permanent failures. A failed G Board is a known fault in several Sony CRT models from the late 1990s and early 2000s.
How to Fix It
Reflowing the solder joints on IC501 and IC5002 can sometimes restore function, particularly if the failure is intermittent. A more permanent fix involves replacing the ICs entirely. This is a specialist repair requiring surface-mount soldering skills. If a compatible replacement G Board can be sourced, board swapping is the most accessible fix for non-technicians.
- 4 Blinks — No Vertical Deflection (V STOP)
What It Means
Four blinks on a Sony CRT TV indicate a vertical deflection failure, also displayed as “V STOP” in the service menu. The vertical deflection circuit is responsible for scanning the electron beam from top to bottom of the screen. When it fails, the picture collapses to a single horizontal line across the middle of the screen, after which the TV mutes the video and displays the fault.
Common Reasons
The vertical deflection IC (commonly IC1509 in many Sony models) is the most frequent point of failure. Supporting components such as Q1505 and related transistors can also cause this fault. Overheating of the deflection circuitry, particularly in TVs without adequate ventilation, accelerates component wear.
How to Fix It
The vertical deflection IC is the first component to inspect and replace. Datasheets and replacement ICs are available for most Sony CRT deflection chips. Before replacing the IC, check for any obviously failed resistors or capacitors in the vertical output stage. This repair requires moderate soldering skill but is well-documented for many Sony Trinitron models.
- 5 Blinks — AKB Circuit Error
What It Means
Five blinks on a Sony CRT TV indicate a fault in the AKB (Automatic Kinescope Bias) circuit. The AKB circuit automatically adjusts the bias voltages to the CRT’s electron guns to maintain correct black levels and picture quality. The TV’s self-diagnostic system monitors this circuit, and if it detects an out-of-range condition, it triggers the 5-blink fault and may run the blink sequence for about 30 seconds before shutting down.
Common Reasons
Faults in the AKB circuit can stem from a failing CRT (particularly ageing electron guns), problems with video output transistors Q705, Q732, and Q761 on the C board, or issues with Q218, Q219, and Q220 on the A board. The TV may also enter IK blanking mode, which can look similar.
How to Fix It
Begin by checking the transistors and components listed above for shorts or open circuits using a multimeter. The CRT guns themselves can be tested with a CRT tester — a weak or shorted gun will throw the AKB circuit out of range. If the CRT is otherwise in good condition, replacing the faulty transistors on the C or A board is the most targeted fix.
- 6 Blinks — A/B Board Overvoltage (Picture Lost)
What It Means
Six blinks indicate that an overvoltage condition has been detected on the A or B board, causing the video to be shut down while audio may continue. The A and B boards in Sony CRT TVs handle audio amplification, power regulation, and various other functions depending on the model. An overvoltage event forces the TV into protective shutdown.
Common Reasons
Failed voltage regulator components on the A or B board are the most common cause. Damaged capacitors or transistors that allow voltage to rise beyond specified limits will trigger the overvoltage protection circuit. A fault on the power supply feeding these boards can also be responsible.
How to Fix It
Measure the supply voltages to the A and B boards using a multimeter to confirm the overvoltage condition. Identify and replace the faulty voltage regulation components. In many cases, this involves replacing a failed transistor or voltage regulator IC. The boards themselves can sometimes be sourced as replacements, though this is increasingly difficult for older Sony CRT models.
- 7 Blinks — High Voltage Shutdown
What It Means
Seven blinks on a Sony CRT TV indicate a high voltage shutdown. The flyback transformer in a CRT TV generates the extremely high voltages required to accelerate the electron beam toward the screen — typically 25,000 to 30,000 volts. When this voltage exceeds the safe threshold (approximately 33 kV), the TV shuts down immediately to prevent X-ray emission and component damage.
Common Reasons
A faulty flyback transformer, a failed high voltage regulation circuit, or problems with the deflection circuits can allow high voltage to exceed safe limits. Damaged focus or screen voltage dividers on the flyback can also contribute to uncontrolled HV rise.
How to Fix It
High voltage CRT work is extremely dangerous and must only be performed by qualified technicians. Even with the TV unplugged, the CRT anode can retain a lethal charge for hours or days. If you suspect a 7-blink high voltage fault, do not open the television. Take it to a certified repair technician. The flyback transformer and associated regulation components will be inspected and replaced as needed.
- 9 Blinks — A Board Audio Failure (Shorted)
What It Means
Nine blinks on a Sony CRT TV indicate that the A Board’s audio section has detected a short circuit and shut down. The A Board typically contains the audio amplifier stages, and a shorted output transistor or amplifier IC will trigger this protection response.
Common Reasons
Output transistors in the audio amplifier stage are the most common point of failure, particularly if external speakers with mismatched impedance were connected. Capacitor failures in the audio output stage can also cause shorts. In some cases, the speaker terminals on the TV become shorted by debris or physical damage.
How to Fix It
Disconnect all external speakers and test the TV again. If the 9-blink code clears, the fault is in the external audio setup. If it persists, open the TV and inspect the A Board’s audio output transistors for shorts using a multimeter in diode-test mode. Replace any shorted transistors with matching components. A complete recap of the A Board’s audio section is advisable if the board is old.