I replace most of the components at the horizontal output, when I put out the LC circuit at collector of the output transistor, the high current disapear, but have small HT, if I put out the C asociates at colletor the HT are increased, but not good.
The Fly-back was replaced, the transistor was replaced, etc,etc,...
I have this projector working without all this components, but have problems in the left side of the screen, distorsions.
IGBTs do not work well at high frequencies. They are not very linear, either. Even if it works, you'll likely wind up with a compressed and distorted picture.
Just put in an equivalent output transistor and call it a day.
Many times, the only problem is hte transistor itself. There is really no way to determine whether or not additiona parts are required until the known defective one is replaced. If there are other symptoms once the transistor is replaced, post them here and we'll guide you to the defective parts.
Check for these power supplies on the Sub deflection board first on the right side of the board there are two Connectors one is a 12 Pin connector CN803 From the top of the connector the wires should read;
30V
Gnd
Gnd
-30V
8.5 V
8.5 V
Gnd
Gnd
-8.5 V
Gnd
Gnd
13.5V
Next is the connector below that one which is a 10 pin connector CN802 they should read
11.7V
11.7V
N.C
Gnd
CTL
Gnd
34V
34V
Gnd
Gnd
Next is a 14 pin connector on the top left side of the board CN801 those should read
34V
34V
Gnd
Gnd
-8.5V
Gnd
8,5V
8.5V
Gnd
13.5
NC
12.5
12.5
Check those supplies and see if they are correct or if any are missing
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Check and replace damaged component/s at its horizontal scan output section circuit. Check the LOT (Line Output Transformer) too for damage. Replace the horizontal scan output transistor. Check the input voltage to LOT. If the voltage is absent check the feeder resistor; if any. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/
Desolder out the horizontal output transistor, and now power on the set. If the set now powers ON, replace the horizontal output transistor. It is faulty. [Collector to emitter or collector to base leak]
Check and replace damaged component/s at its horizontal scan output section circuit. Check the LOT (Line Output Transformer) too for damage. Replace the horizontal scan output transistor. Check the input voltage to LOT. If the voltage is absent check the feeder resistor; if any. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/
Check the horizontal output transistor for collector to emitter leak.
Short circuited component at its main board. Check and replace damaged component/s at its horizontal scan output section circuit. Check the LOT (Line Output Transformer) too for damage. Replace the horizontal scan output transistor. Check the input voltage to LOT. If absent check the feeder resistor; if any. If you wish to get some details; check the site linked here. Viewing it in "Mosaic" will make surf easy. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/ Give a special attention to its horizontal output transistor. Replace it, and check. Check this device for collector to base, or collector to emitter leak. Even a slightest leak, will cause sivere problem.
Check the frequency of oscillation at the base of horizontal output transistor. It should be around 15.6KHz. If there is no frequency, the horizontal osciallator jungle IC should be suspected.
Hello Check the supply rail to LOT. If LOT [Line Output Transformer] is fauty, it will take tremendous current from the SMPS power supply output, and the overload sensor circuit will be energiised and the supply to the whole system will sut OFF. That is happening eith your TV now. Just desolder out the horizontal output transistor, the transistor that drives the LOT, and switch the set ON, and see whether it stays on or not. If stays on, check the collector to emitor resistoance of the horizontal output transistor. If there is any short with it, replace it and switch ON the set for a short time, say 5 seconds or so, and check whther the replaced transistor gets overheated. If it overheats, make sure that the LOT said above has damaged, and must be replaced with same type and number. If the fault is with the horizontal out put transistor, the set will work normally after replacing it. The components can be bought from local electronic spare part shops at your town. OK.
A protection circuit has cut in - possibly due to a fault in the line output stage (flyback transformer could be short-circuit and horizontal output transistor could also be shorted).
Assuming the power supply/HT rail is all OK, replace the above parts, touch up any suspect solder joints, check and replace any capacitors (electrolytic and the tuning caps in the collector of the horizontal transistor - always replace these caps (rated at around 2kV - 6kV) whenever you replace the flyback)
Shrinking picture is a voltage regulation problem in the switch mode power supply, Possibly a cap used in the feedback circuit. Or an over current condition on the B+. This is a very tech intense repair because there is no magic bullet. If it is shrinking on bright scenes then you can bet it is a regulation problem, bright scenes draw more current from the power supply causing this effect. I would not suspect the horiz output because the regulation for this circuit usually comes from the main switch mode power supply. One diagnostic is to monitor the B+ going to the horizontal output and see if it fluctuates. If so you can bet it is a cap or optical coupler in the switch mode circuit.
Are you talking about the LV power supply or the HV power supply? The terminology your using is related to the horiz drive circuit. Have you checked the B+ off the regulator which should be about 120v or, it will on the pc bd for the correct voltage. Do you have sound? If you do then you will have to use use your scope to see if you have proper drive at the base of the Horizontal Output Transistor. Then we can go from there. Oh, by the way I can tell by the voltage readings you stated both of those transistors of turned off.
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