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Verticle scan has failed. Deflection yoke checks good. Suspect problem is in driver. High voltage is Ok and horizontal deflection is working. Video is seen on the horizntal line across the middle of the CRT. Some of the parts on the circuit board look as though they may custom. I could realy use a schmatic, board layout and parts list. Failing finding a custom part, it is posible to make an outboard module to replace it. I'm NOT going to pay out a large sum of money. I can put this TV in the re-cycle.

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Depending upon what make, model and age your set is. If the frame scan has stopped there may be either an IC that has failed or transistors. If it is an older Hitachi, then a frame module will be required, if a Sony, a frame IC.
There are four wires from the scan coils. two go the line and two to the frame. The line you say is OK, then the other two go to the frame output stage. Check the IC/Output Transistors/Module as required.
Hope this helps.

Posted on Nov 06, 2010

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Absence of horizontal scan signal to the deflection yoke. Check all the connection to the deflection yoke. If found OK, the deflection yoke winding [horizontal] is open. If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/

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sounds like a video board died..

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Absence of Horizontal sweep. Check the connections to deflection yoke for any loose. Unplug the the wire connection plug that connect the deflection yoke to main board and re-plug it back. Check the solder connections to this connection pin for any loose solder terminals.

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Failure of the horzontal linerity coil, possible dry soldering on the board of the components- resistors and capcitors- in the horizontal coil circuit . Also failure of the deflection coil- YOKE- in the crt. So check the coils and the circuit around this section as the rest of circuit seems OK.

Apr 06, 2011 | Televison & Video

1 Answer

No verticle deflection


NO VERTICAL DEFLECTION MEANS YOU HAVE A HORISONTAL BAR IN THE SCREEN?, Check the power supply for the correct voltage to the vertical circuit, check the vertical DRIVER circuit, check the conductivity of the YOKE (vertical winding) on the neck of the tube

if you have a VERTICAL bar in the screen (common mistake) check all of the above relating the HORISONTAL circuit

good luck!

Jan 13, 2011 | Sanyo DS27800 27" TV

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Dear sir i have samsung 21 inch flat television now horizontal drive transistor fails after few hours i replaced 3 times the same transistor(tt2222) but again geting fails so pls let me know what is...


Hello
You just replace the freewheeling capacitor, normally come up to a value of 5600pf 2000V or so, connected to the collector of the horizontal output transistor, fitted very close to the collector lead. Replace the yoke return capacitor, 0.33uf or so also. Usually samsung sets use no heatsink for the horizontal output transistor. You just put a small heatsink to it and check. If it doesn't overheat, you can remove it later.
You can suspect the deflection yoke also for shorted winding. To check this. pull out the CRT base board out of the neck of the picture tube, place it where it doesn't get short circuited, and unplug the deflection yoke connection from the main board, and switch on the set. See whether the transistor overheats now. If it doesn't overheat, suspect the deflection yoke for shorted turns of winding inside it. Till the transistor overheats, suspect the LOT.
NOTE: Never switch on the set while unpluging the deflection yoke connection plug from the circuit board, without dismandling the CRT base board. CRT may get damaged, with a black burned spot inside the center of the screen.
OK.

Dec 15, 2010 | Samsung CXJ1952 19 in. Combo

1 Answer

Horizontal driver too hot, no eht, power suply is ok.


Hello

If horizontal output transistor gets over heated, the either LOT or Deflection Yoke may have some short in it. You just pull out the picture tube base card from the picture tube neck, and place it somwhere. so that it never gets in contact with any other circuit parts of the TV. Pull out the deflection yoke plugin and put the tv ON, and see whether it overheats now or not. If it overheats no also, LOT is defective, and should be replaced with a same type and number. If it does't overheat now. put the unpluged yoke connection, and switch it ON. If it gets overheats, there is some short in between the horizontal winding section inside the deflection yoke. Caution:- Never place the picture tube base board connected to it, while deflection yoke is disconnected. OK.

Dec 06, 2010 | Televison & Video

1 Answer

Monitor no raster power has been ok


Hello,

The screen is blank with no raster at all. There are indications that the channel numbers are changing in the display. This indicates that some of the low voltages are present but these may be derived from the standby supply.
Assuming there is no deflection and no High Voltage, you either have a low voltage power supply problem, bad start up circuit, or bad horizontal output transistor (HOT) or other bad parts in the horizontal deflection.

Check for bad fuses.

(If you have High Voltage as indicated by static electricity on the front of the screen and you hear the high pitched whine of the horizontal deflection when it is turned on, then the following does not apply).

Use an ohmmeter to test the HOT for shorts. If it is bad, look for open fusable resistors or other fuses you did not catch.
Assuming it is good, measure the voltage on the collector-emitter of the HOT (this is safe if there is no deflection). You should see the B+ - probably between 100 and 150 V.
If there is no voltage, you have a low voltage power supply problem and/or you have not found all the bad/open parts.
If there is voltage and no deflection (no high pitched whine and no HIGH VOLTAGE), you probably have a start up problem - all TVs need some kind of circuit to kick start the horizontal deflection until the auxiliary power outputs of the flyback are available. Some Zeniths use a simple multivibrator for this - a couple of transistors. Others power the horizontal osc. IC from a special line-derived voltage. The multivibrator type are sometimes designed to fail if someone keeps turning the set on and off (like kids playing) since the power rating is inadequate.
Test the transistors if it is that type with an ohmmeter. If one is shorted, you have a problem. The usual way a TV service person would test for start up problems is to inject a signal to the base of the HOT of about 15.75 kHz. If the TV then starts and runs once this signal is removed, the diagnosis is confirmed. This is risky - you can blow things up if not careful (including yourself).

If you hear the high pitched whine of the deflection and/or feel some static on the scree, confirm that the horizontal deflection and high voltage are working by adjusting the SCREEN control (probably on the flyback). If you can get a raster then your problem is probably in the video or chroma circuits, not the deflection or high voltage.

hope this helps......

Aug 06, 2010 | SAMTRON 77V 17" CRT Monitor

1 Answer

Too dark and the red and green color too much..


Hello,
first to check waveforms going into the vertical output stage. The supply voltage is probably correct since that often determines the size. It almost sounds like the waveform rather than being mostly on (active video) and off for the short blanking period is somehow only on during the last part of the active video thus giving you just the bottom of the picture. If there is a vertical output IC, it may be defective or the blanking input to it may be corrupted. The problem may be as far back as the sync separator. Then again who knows, maybe wait for the schematics. 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.
Since you have high voltage, the horizontal deflection circuits are almost certainly working (unless there is a separate high voltage power supply - almost unheard of in modern TVs and very uncommon in all but the most expensive monitors).
Check for bad solder connections between the main board and the deflection yoke. Could also be a bad horizontal coil in the yoke, linearity coil, etc. There is not that much to go bad based on these symptoms assuming the high voltage and the horizontal deflection use the same flyback. It is almost certainly not an IC or transistor that is bad.

May 16, 2010 | Philips Magnavox 9P6034C 60" Rear...

1 Answer

Only getting vertical lines on screen..no picture


Tell me are they Verticle lines or verticle LINE. If it is one line, either yoke( a coil kept at the neck of the tube).A yoke has two coils for Vertical and Horizontal for deflections.When the Horizontal deflection coil is opened you get a vertical line which is a single bright line. There another small linear coil on the board connecting the horizontal coil of the yoke.This is a simple fault and tracing is very easy and not expenssive.Only if the yoke is open, it might be bit costly.And that is a rare case.

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