Question about Sony KV-20FS12 20" TV

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The set goes into a overvoltage mode

The set goes into a over voltage mode it looks like.I work for a small shop and I don't have a manual yet, i've got one on order. When the customer brought it in she said that the tv and also another one had been hooked up to the same UPS and both went out with in two to three weeks I did not look at the first set. The sony when powered up the LED on the front blinks 3 times, then it shuts down and blinks 4 times as long as it stays powered up. I replaced the STR regulator and I have the same problem. May be someone can give me a heads up on what might be defective. I would think the power supply, the B+ on the horz out collector is 136vdc. Not sure if that's correct.

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A 20In set would probably be around 136v (give or take) while running and would go much higher if it was going into HVS (High Voltage Shutdown) 180v or so. The power supply is working (you have voltage).
Do you have a glow in the neck of the CRT? If not then it may be a bad resistor for the crt heater circuit. Most tubes use the top two pins on the neck socket for the heater, trace them back looking for a resistor, or simply test for voltage at the heater pins (AC), should be low 2-5 volts. If it is shutting down check the Horizontal Output Transistor (HOT) by using an ohm meter (with power disconnected :) ground the black lead and hold the red lead on the center pin of the HOT. Ideally you want an open circuit reading or very high resistance (MOhms), if you have low resistance it means either the HOT or the Flyback Xfmr is bad.
Hope this helps :)

Posted on Mar 11, 2008

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Tv is on an the picture blinks back and forth to black


Hello
This is due to over voltage. Not related to supply in overvoltage, but the overvoltage that goes to the main board to this TV. Most TVs works oan a range of 85 to 120VDC. This voltage is generated from the internal power regulator. If the power regulator have any fault, the supplied voltage to the main board may either high or low. In both cases, the main system control IC on board, will detect it and will give you this symptoms.
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No Picture and Lttle red light next to power buttons blinks for about 30 seconds


First thing to do is reset ( see link below) and see if it resets otherwise if problem continues it will need some work

Seven blinks - High voltage shutdown. The high voltage has exceeded 33k and the unit goes immediately into safety shutdown. Check power supply regulation and horizontal circuits. There are some common breakdowns in the High Voltage circuits in this set. One is the flyback transformer. Another is a small high voltage capacitor in the sweep corrction circuit. There is a cap that goes open in a high voltage circuit (C6532) which needs to be replaced.
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I've got an old philips TV that worked perfectly until last night. It now just shows a narrow band about 2 inches wide of picture horizontally across the screen no matter what I try. Is she dead? its...


No, you can't pin this on the kids. The trouble is in the TV's vertical output circuit. It may be just a matter of bad connections, and you can see if giving the set a whack has any effect. Sometimes the picture will pop back to full height if it's just a connection issue. More likely, some of the capacitors in the circuit or possibly the vertical output device itself need to be replaced. Over time, these parts can wear out (electrically, not mechanically) and lead to a variety of picture problems. The good news is that the parts themselves aren't expensive, but the labor to repair the TV is. I don't know what kind of labor prices shops are charging these days, but I'd give a ballpark figure of $75 to $100 for the repair. Most shops have a charge to check a TV and give an estimate; the charge is usually applied to the repair if you get the set fixed. I've been away from shop service now for a long while, so I could be way off.

You say the set is old, but not exactly how old. Picture tubes don't last forever, and sooner or later the one in this set will go. It may lose focus or develop color problems, or burn out like a light bulb, or have other internal problems. Bottom line is it's on borrowed time, and there's no way to know whan the end will come. This may be something to think about if you consider repairing this set. Rather than sink money into repairing an older set, this might be a good time to shop around for a replacement. If you don't want to go for a new flat-screen, check eyour local Craig's list or visit resale shops. Lots of TV sets become available as people buy new ones. I've seen many good sets in a Goodwill store near my home in the $20 to $50.

Jul 15, 2011 | Philips Televison & Video

1 Answer

My picture is all scrunched up in the middle of the screen,black on the top and bottom,otherwise the width of the screen is fine! Is this a picture tube going bad or just an adjustment?


There's trouble in the set's vertical output circuit. Often this is because of bad solder connection, but there could be parts that need to be replaced as well. It isn't the picture tube going bad, though, so the set could be fixed. (Actually, even a bad picture tube can be replaced, but when the tube goes it's cheaper to buy a new TV!) Often just resoldering the connections in the affected area brings the picture back to full height. It's not unusual for capacitors in that area to wear out with age, but they're inexpensive parts.

The trouble with TV repairs is the labor cost. If you don't know anyone who has the skills to check over a circuit board and do electronic soldering, and to check and replace parts, you'll need to have a professional do it. The total cost of repairing a small TV might make it worth spending a little more on a new flat-screen LCD. They've really come down in price.

Most shops charge a fee (applied to the repair if you go ahead) to check the set and give a repair estimate. If you don't mind the gamble, get the set checked. Otherwise, start looking for a good sale on something new.

Jun 29, 2011 | RCA F27442 27" TV

1 Answer

How can I get headphones to work with my Symphonic WF203 TV?


This set doesn't have a headphone jack, nor does it have RCA audio output jacks. Without one or the other, you're out of luck connecting headphones to this TV.

I remember a product some years ago that allowed adding headphones using a small microphone placed in front of the speaker. This was hooked to a little amplifier that ran the headphones so the volume could be independently controlled. It was marketed as a way to let "hearing-impaired" family members listen to TV shows without needing to make it uncomfortably loud for others. I haven't looked, but something similar might still be available. It's cumbersome, though, and needs power, plus maybe being costly if you find one.

It's possible to add a headphone jack, but you need to know how to do electronic soldering. Find a spot on the case where you can make a hole and mount a headphone jack, then wire it to the speakers. If you want the headphones to cut off the speakers when plugged in, you need a switching jack, and the speaker wires need to be cut and connected to the correct terminals. The switch built into the jack then disconnects the speakers when the headphone plug is in. If you don't need to turn off the speakers it's a little easier. You just need to wire from the jack to the speaker terminals. I've added jacks on quite a few sets. If you don't feel up to it and don't know anyone who is, you can see if a TV shop (if there are any left in your area!) would do it. (The shop I used to work for charged about $20, including the jack, but that was over 10 years ago now.)

Good luck, and thanks for using Fixya!

Jun 12, 2011 | Symphonic WF20D4 TV

1 Answer

Light blinks three times on my sony wega tv model #kv-32hs500 but will not come on .


Hello
Three times blinking denotes that there is some overvoltage in the secondary DC supply rail inside your TV. It is called Over Voltage Protection [OVP]. Due to this fault as soon as the set is switched on, it goes to standby state and the front LED blinks tree times, and won't come up again.

It may be due to power supply regulator section fault inside your TV. To find out you have to open the back cover of the TV. As high as 32KVDC [32,000 volts DC], points are there inside your TV, while it is working, all care should be taken before open it. Even though the TV is switched off, the final anode of the picture tube will have a charge upto this voltage for sometime and it is dangerous. So be care.

After opening the TV, locate the power regulator section. It can be easly located, that the AC input goes to that section, after the switch connection. You have to pull out the printed circuit board and should keep it upside down for repair work. During this time, sometimes you may have to unplug some plugin connections from the board, and keep it marked, so that you have to refit it there later. You must have some concept of soldering and more patience to do this work.

After the board has been pulled out, loate if there is any soldering loose contact to the regulator Ic or its nearby components. As they will heatup during working, continous heat up and cooling may make some of the solderings, and it is normal in practice. As it is very difficult to locate the loose solderings by naked eye, resolder all suspected points with applying a little bit of extra solder. Never make any short between them while soldering. Normally this will rectify the problem. If it does not help, replace the power regulator with same type and number; [ Normally in Sony sets they uses STR type regulators on power side], and it is a very stable and High Accurate device, and should be replaced with the same type and number.

Check if now the secondary DC voltage at the secondary voltage rail of your Tv. Now it will be zero due to overvotage shutoff. Locate the pin to which the DC power goes into the LOT [Line Output Transformer], and make a small break on its print that carries supply to it. Be sure to make a small break, as we have to rejoin it after the fault detection. Connect a 100W filament type bulb between the DC supply Rail and to the Negative. Switch on the set. The bulb will glow, and take the votage across its filament. It should be between 125 and 130VDC, for 32" Sony TVs. if it is found abnormal, you can make sure that power regulator section has some trouble in it. Three blinks shows that symptom in Sony TVs. Ok.

Oct 31, 2010 | Sony Televison & Video

1 Answer

My tv turns on color works, sound works, then about 45 seconds after it is on, it dims out and shuts off


Hello
Your TV has an internal voltage regulation trouble. Set switches on, finds some voltage troube, normally overvoltage and shuts down. Your TV has an internal voltage regulator. Check if its secondary voltage is more than 110VDC on load. It can be vary from 105V to 115VDC. If it higher than 115v or so, your TVs system control Ic will sense it and shuts the whole supply voltages to down. It is a protection done by the manufacturer. You just check it. In most televisions there will be a preset onboard control to adjust it. For that you need the proper measuring equipments and some skill and more patience.

Oct 17, 2010 | Symphonic Televison & Video

2 Answers

Tv keep going on standby when you turn it on


tv goes into standby all the time if a power supply is not fine, what happens is that a power supply produces two voltages, one small one powers a standby components and bigger voltage powers a line transformer which later produces more small voltages,
then later cancels the first small voltage.

chec your power supply semi conductors like, transistors, diodes and small value resistors, on your power supply. some power supply uses a IC to oscillate a ht. so check a supply at a w/shop.

Feb 07, 2009 | Goodmans 257NS 20" TV

1 Answer

Tv repair


You don't give much in the way of details... How long does it stay on? Long enough to give a picture and audio?? Or maybe 10- 30 minutes?

If it only comes on momentarily, not even long enough to give video, then it could be going into Hi-voltage shutdown, probably indicating an overvoltage condition. This could be caused by a voltage regulator failure. Troubleshooting this is best done by a qualified technician.

If it stays on for several minutes, maybe even 30 minutes or so, then goes off, bad solder connections might be the culprit. A modest whack or bump on the side or back of set might confirm this. Whack it... if set dies, you likely have a bad connection problem. If you have good eyes, a solder iron and solder, and know how to solder, then you might be able to find the bad connection(s) on the chassis. Common locations for this are in the horizontal deflection, power supply or vertical deflection portions of the circuit.

Jan 08, 2008 | Televison & Video

1 Answer

Set comes on with e.h.t for 4 sec,then goes off B=142v


Hello,

The problem you described is a case of the shutdown circuit being activated. This is either due to an overcurrent or overvoltage condition within the circuirty of the TV set. This could be an open or shorted component in the High Voltage section of the TV, or an open or shorted component in the low voltage power supply section of the TV. In any case If I were troubleshooting this TV I would check the Horizontal out put transistor to see if it had shorted or opened at one of its junctions. I would also check to see if any of the voltage regulators had shorted or opened. I would also suggest that you check to see if you see any signs of burnt components (note the section).

If you do not have a background in Electronics, I would suggest that you take the TV to a qualified TV shop for repairs. This is because the work that needs to be done is not sinmple, and serious harm can result if you are not careful.

I wish you well on the repair of your TV.

Thank you,
Shuttle83

Nov 26, 2007 | Televison & Video

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