Tip & How-To about Televison & Video

Diagnosing and repair of TV High Voltage problems.

Your TV is dead or perhaps the turn on relay clicks and immediately clicks again, followed by your standby light blinking a specific code. For each TV the code is different. To find out your code google "(your brand name) error codes". This should return the listing of codes for your unit. Check the code to see if it is the high voltage section with the problem.

The hardest working section of any TV is the high voltage section. This does not apply to flat screens and DLPs only CRT projection units and conventional direct view units. The flyback get hot and is made of many windings of very thin wire which is only shellaced to insulate it. Over time the windings coating breaks down and the windings short together. This can happen in as little as several years. Once shorted there is less resistance and the current being pushed through the flyback increases. This overloads the Horizontal Output Transistor which gets hot and fails. This in turn causes the low voltage power supply to detect the overload and not allow the unit to start up, giving you the error code blinks.

The flyback is generally near the rear of the unit and is cylindrical with large rubber wire or wires if projection coming out of it and going to a rubber cup on the CRT or CRTs. Near the flyback will be a large heat sink with a large transistor mounted to it. With the set unplugged check the HOT with a DMM on diode scale for resistance. The leads of the HOT should be marked on the circuit board (C= collector, B=base,E=emittter). If the HOT has 0 resistance between all the leads it is shorted and you need to replace both it and the flyback.

You should be able to obtain both parts at http://www.encompass.com or http://www.shopjimmy.com . Unsolder both parts and remove from the board. When installing the new HOT be sure to clean off the heat sink and apply new heat sink compound available from the parts supplier. The flyback also will have two additional wires to remove and replace. One goes to the CRT board and may plug into a plastic box on the CRT jack or be soldered into the board depending on the model. This process should be self explanatory if you study it a while.

Depending on whether you have a projection TV or a Direct View TV the procedure is a little different. I will describe the procedure for a direct view TV first.

The 2nd anode lead (large red rubber wire going to the CRT) is plugged into the CRT and may have 48 kilo volts on it! Discharge the potential to the ground strap (bare wire going around the CRT) using an insulated screwdriver and a wire with gator clips on each end. If the CRT was storing power there will be a spark and loud snap when you make contact. Once discharged the tube is safe. Pull back the rubber boot and remove the wire from the hole in the tube. Install the new flyback wire. Solder the new flyback to the board reassemble everything and turn on. If you were successful the unit will start. You will need to set the focus and screen drive using the two potentiometers on the back of the flyback. Top is focus, bottom screen drive. Turn up the screen drive to get a picture. Tune to a channel with text. Turn focus to get the sharpest image. Tune to a channel which has both black and white in large amounts. Turn up screen drive until the black just begins to light up or starts looking gray then back it off slightly and you should be done with the unit. Be careful while adjusting the flyback as the set will have lethal voltages in it.

Now for the flyback on a projection TV. It will have 4 large rubber wires coming out of it. If the new one came with wires they should be removed at the HV divider block (located at the front of the set normally, just follow the wires to their end) if not they should be removed at the flyback. To remove at the flyback, which is the most common hookup, slide the rubber boot off the post and using needle nose pliers pry the cable out. It should have a bare end which connects to a clip at the bottom of the new unit. Do them one at a time to avoid getting them wrong. When done you may have to adjust the focus and screen drive but it will be on a separate box called the HV divider block usually near the front of the unit behind the grill. Same process as listed above for the direct view set. If your unit still does not run you may also have to replace the HV divider block. All safety rules apply here also.

That should conclude the repair and if successful your set will work. If the unit still does not work go to my tip on troubleshooting at http://www.fixya.com/support/r4425277-basic_direct_view_tv_troubleshooting which explains the basic troubleshooting method to find any problems in standard televisions.

Thanks for using FixYa.

hardrocko

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1 Answer

The stand by light keeps blinking, this has happened before but then the TV came on. What to do as it has been blinking for a long time now.


The self-diagnostic function of the projection TV will cause the STANDBY light to blink or flash when the television detects an issue. The number of times the STANDBY light flashes corresponds to a specific issue. As per the two examples below, some of the issues may be resolved without the need for service.
  • If the STANDBY light flashes three times in sequence, the lamp cover is not securely attached. Reattach the lamp cover to resolve this issue.
  • If the STANDBY light flashes four times in sequence, the TV may be overheating. To resolve this issue, ensure that the back of the TV is well ventilated.
If the flash sequence is not listed above or the light continues to flash, follow the steps below to perform a power reset:
  1. Turn off the television. IMPORTANT: For a projection TV that uses an internal lamp, wait 5 minutes after turning off the TV to allow the lamp to cool before continuing with the following steps.
  2. Unplug the TV power cord from the electrical outlet.
  3. Let the TV remain without power for 60 seconds.
  4. Plug the power cord back into the electrical outlet. NOTE: If the TV is plugged into a power strip or surge protector, remove it from the power strip or surge protector and plug it directly into the wall outlet. If the issue is resolved, the problem is with the power strip or surge protector and not the TV.
  5. Turn on the television. NOTE: If the TV does not turn on immediately, the fan may need to finish its cycle. This is part of the cooling process for some projection TVs and is normal operation. After the fan turns off, attempt to turn the TV on again.
If the issue is still unresolved after following all of the troubleshooting steps,service may be required. Please note the number of times the STANDBY light flashes and relay that information to the service center.

Nov 15, 2010 | Sony Televison & Video

1 Answer

KP57WV600 SCREEN TURNS GREEN THEN BLANK


The self-diagnostic function of the projection TV will cause the STANDBY light to blink or flash when the television detects an issue. The number of times the STANDBY light flashes corresponds to a specific issue. As per the two examples below, some of the issues may be resolved without the need for service.
  • If the STANDBY light flashes three times in sequence, the lamp cover is not securely attached. Reattach the lamp cover to resolve this issue.
  • If the STANDBY light flashes four times in sequence, the TV may be overheating. To resolve this issue, ensure that the back of the TV is well ventilated.
If the flash sequence is not listed above or the light continues to flash, follow the steps below to perform a power reset:
  1. Turn off the television. IMPORTANT: For a projection TV that uses an internal lamp, wait 5 minutes after turning off the TV to allow the lamp to cool before continuing with the following steps.
  2. Unplug the TV power cord from the electrical outlet.
  3. Let the TV remain without power for 60 seconds.
  4. Plug the power cord back into the electrical outlet. NOTE: If the TV is plugged into a power strip or surge protector, remove it from the power strip or surge protector and plug it directly into the wall outlet. If the issue is resolved, the problem is with the power strip or surge protector and not the TV.
  5. Turn on the television. NOTE: If the TV does not turn on immediately, the fan may need to finish its cycle. This is part of the cooling process for some projection TVs and is normal operation. After the fan turns off, attempt to turn the TV on again.
If the issue is still unresolved after following all of the troubleshooting steps, service may be required . Please note the number of times the STANDBY light flashes and relay that information to the service center.

Sep 22, 2009 | Sony KP-57WV600 57" Rear Projection...

1 Answer

sony kv-27s42 no picture no sound can here relay click


I will look up your specific model to be sure, but teh 3 blinks usually mean a power supply problem. Stay tuned for more...

Dan

Aug 23, 2008 | Sony KV-27S42 27" TV

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