Vertical deflection - Sanyo DS25390 TV

May not be an easy fix:

A single horizontal line means that you have lost vertical deflection. High voltage is most likely fine since there is something on the screen.

This could be due to:


Dirty service switch contacts. There is often a small switch located inside on the main board or perhaps accessible from the back. This is used during setup to set the color background levels. (On some sets, this is located on the CRT neck board and may be a jumper plug or other means of selecting service mode - not an actual switch.)
When moved to the 'service' position, it kills vertical deflection and video to the CRT. If the switch somehow changed position or got dirty or corroded contacts, you will have this symptom. Flip the switch back and forth a couple of times. If there is some change, then replace, clean, resolder, or even bypass it as appropriate.


Bad connection to deflection yoke or other parts in vertical output circuit. Bad connections are common in TVs and monitors. Check around the pins of large components like transformers, power transistors and resistors, or connectors for hairline cracks in the solder. Reseat internal connectors. Check particularly around the connector to the deflection yoke on the CRT.

Bad vertical deflection IC or transistor. You will probably need the service manual for this and the following. However, if the vertical deflection is done with an IC, the ECG Semiconductor Master Substitution guide may have its pinout which may be enough to test it with a scope.

Other bad parts in vertical deflection circuit though there are not that many parts that would kill the deflection entirely.

Loss of power to vertical deflection circuits. Check for blown fusable resistors/fuses and bad connections.

Loss of vertical oscillator or vertical drive signals.
The most likely possibilities are in the deflection output stage or bad connections to the yoke

Hello,

Most probably the vertical deflection amplifier is failing. The most common part that fails is the vertical output transistor.
The set is too old to find documentation on part numbers and descriptions. Probably the part is no longer available and you will need the assistance of someone who can help you find an equivalent transistor that will do the job.
Of course, without testing we cannot be certain the failure is the output transistor. It could be from something else such as the voltage regulator that feeds the dc line to the vertical section. Could be the vertical synchronous level that goes too low to trigger the vertical sweep generator.

Other bad parts in vertical deflection circuit though there are not that many parts that would kill the deflection entirely.

Loss of power to vertical deflection circuits. Check for blown fusable resistors/fuses and bad connections.

Loss of vertical oscillator or vertical drive signals
Good luck.

Hello,
you can do this yourself by opening the back cover of the television
CAUTION: To prevent damage to the CRT phosphors, immediately turn down the brightness so the line is just barely visible. If the user controls do not have enough range, you will have to locate and adjust the master brightness or screen/G2 pots.

A single horizontal line means that you have lost vertical deflection. High voltage is most likely fine since there is something on the screen.

This could be due to:

Dirty service switch contacts. There is often a small switch located inside on the main board or perhaps accessible from the back. This is used during setup to set the color background levels. (On some sets, this is located on the CRT neck board and may be a jumper plug or other means of selecting service mode - not an actual switch.)

When moved to the 'service' position, it kills vertical deflection and video to the CRT. If the switch somehow changed position or got dirty or corroded contacts, you will have this symptom. Flip the switch back and forth a couple of times. If there is some change, then replace, clean, resolder, or even bypass it as appropriate.

Bad connection to deflection yoke or other parts in vertical output circuit. Bad connections are common in TVs and monitors. Check around the pins of large components like transformers, power transistors and resistors, or connectors for hairline cracks in the solder. Reseat internal connectors. Check particularly around the connector to the deflection yoke on the CRT.

Bad vertical deflection IC or transistor. You will probably need the service manual for this and the following. However, if the vertical deflection is done with an IC, the ECG Semiconductor Master Substitution guide may have its pinout which may be enough to test it with a scope.

Other bad parts in vertical deflection circuit though there are not that many parts that would kill the deflection entirely.

Loss of power to vertical deflection circuits. Check for blown fusable resistors/fuses and bad connections.

Loss of vertical oscillator or vertical drive signals.

The most likely possibilities are in the deflection output stage or bad connections to the yoke.

Hello,


CAUTION: To prevent damage to the CRT phosphors, immediately turn down the brightness so the line is just barely visible. If the user controls do not have enough range, you will have to locate and adjust the master brightness or screen/G2 pots.

A single horizontal line means that you have lost vertical deflection. High voltage is most likely fine since there is something on the screen.

This could be due to:

Dirty service switch contacts. There is often a small switch located inside on the main board or perhaps accessible from the back. This is used during setup to set the color background levels. (On some sets, this is located on the CRT neck board and may be a jumper plug or other means of selecting service mode - not an actual switch.)

When moved to the 'service' position, it kills vertical deflection and video to the CRT. If the switch somehow changed position or got dirty or corroded contacts, you will have this symptom. Flip the switch back and forth a couple of times. If there is some change, then replace, clean, resolder, or even bypass it as appropriate.

Bad connection to deflection yoke or other parts in vertical output circuit. Bad connections are common in TVs and monitors. Check around the pins of large components like transformers, power transistors and resistors, or connectors for hairline cracks in the solder. Reseat internal connectors. Check particularly around the connector to the deflection yoke on the CRT.

Bad vertical deflection IC or transistor. You will probably need the service manual for this and the following. However, if the vertical deflection is done with an IC, the ECG Semiconductor Master Substitution guide may have its pinout which may be enough to test it with a scope.

Other bad parts in vertical deflection circuit though there are not that many parts that would kill the deflection entirely.

Loss of power to vertical deflection circuits. Check for blown fusable resistors/fuses and bad connections.

Loss of vertical oscillator or vertical drive signals.

The most likely possibilities are in the deflection output stage or bad connections to the yoke.

Hello,

CAUTION: To prevent damage to the CRT phosphors, immediately turn down the brightness so the line is just barely visible. If the user controls do not have enough range, you will have to locate and adjust the master brightness or screen/G2 pots.

A single horizontal line means that you have lost vertical deflection. High voltage is most likely fine since there is something on the screen.

This could be due to:

Dirty service switch contacts. There is often a small switch located inside on the main board or perhaps accessible from the back. This is used during setup to set the color background levels. (On some sets, this is located on the CRT neck board and may be a jumper plug or other means of selecting service mode - not an actual switch.)

When moved to the 'service' position, it kills vertical deflection and video to the CRT. If the switch somehow changed position or got dirty or corroded contacts, you will have this symptom. Flip the switch back and forth a couple of times. If there is some change, then replace, clean, resolder, or even bypass it as appropriate.

Bad connection to deflection yoke or other parts in vertical output circuit. Bad connections are common in TVs and monitors. Check around the pins of large components like transformers, power transistors and resistors, or connectors for hairline cracks in the solder. Reseat internal connectors. Check particularly around the connector to the deflection yoke on the CRT.

Bad vertical deflection IC or transistor. You will probably need the service manual for this and the following. However, if the vertical deflection is done with an IC, the ECG Semiconductor Master Substitution guide may have its pinout which may be enough to test it with a scope.

Other bad parts in vertical deflection circuit though there are not that many parts that would kill the deflection entirely.

Loss of power to vertical deflection circuits. Check for blown fusable resistors/fuses and bad connections.

Loss of vertical oscillator or vertical drive signals.

The most likely possibilities are in the deflection output stage or bad connections to the yoke.
Good luck..

There is a failure in the vertical deflection circuit. Typically there is a vertical output i.c. that provides the deflection vertically. The i.c. itself is a fairly common component to fail. There are some lower power circuits that feed this output device that also could be the problem. When the electron beam in the tube is not deflected vertically it "writes" only horizontally across the center of the screen thus resulting in a single trace. Be careful not to leave this at high brightness for any extended time as it can "burn in" that area of the screen. Unless you are a "techi" this is a job for a qualified technician. Troubleshooting would be in the vertical deflection section of the set. Most of the parts are not expensive in themselves, except for the deflection yoke which sits around the neck of the tube. The cost to repair would typically be the shop labor.

Look up for faulty Elkos in the vertical Stage near the powersuply abd then find the Vertical IC with are fit near by the highvoltagetransitor

Hi,
Get service manual / schematics from HERE and find why vertical uotput IC is blown in your TV.
Service Manual will also give you info how to perform vertical adjustments.
Hope this info will help you to resolve problem.

No vertical is always an affordable fix.
- failed (dried out) electrolytic caps in the vertical circuit
- failed vertical IC
- failed power to the vertical circuit.
Hope Ya Fix It

You have a bad vertical output IC, or the sweep power supply that drives the IC is bad. Your going to need the service schematic diagram and the know how to fix solid state electronics.