Question about Standard (CRT) Televisions

1 Answer

2 hi-voltage resistors r2709 r4704 burnup when turn on power switch

Resistor r4704 82k hooks to pin 4 of flyback @ to ground.r2709 27k hooks to pin 4 too. @feeds to ic u1001 pin 31 beam sense in .hope you can help me. thank you . ED

Posted by on

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that gotĀ 5 achievements.

    Champion:

    An expert who has answered 200 questions.

    Governor:

    An expert whose answer gotĀ voted for 20 times.

  • Expert
  • 252 Answers

The resistor you mention is from ABL? if so, then the plyback had a problem

Posted on Oct 11, 2008

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Why does this Sharp CRT TV turn on then click off a few seconds later?


TV with Black Blank Screen Repair How to Troubleshoot ...

? 3:16
www.youtube.com/watch?v=kFdVi2ejfzA
May 8, 2014 - Uploaded by ShopJimmy.com
TV Repair Help for a TV With a Black No Image on the Screen - Troubleshooting ... Click Here to BUY TV ...

Oct 31, 2015 | Sharp Standard (CRT) Televisions

1 Answer

I have a sony color rear projector model kdp-51ws550 seial 9710095 manufacture june 2004 it turns on and it goes off the stand by light keeps blinking


Hi there,

Well If you simply push the power button on the front, does the stand-by LED turn off or start flashing? Anyway the G Board is definitely suspect. Try measuring the 5 volt DC stand-by power supply. That is best done at connector CN605, between pin 10 and cold ground (any metal chassis part). 

If that voltage isn't there, carefully measure the voltage across resistor R607 ( not to any ground). You should get something very low, a couple of volts (if that much). If you get a couple hundred volts, that resistor is open, and that happened because transistor Q601 shorted.
Note. You need a ohms meter to check that all. please do not try this if you do not know how to do that.......
Please post comments for more help or information........

Good Luck!!

Thanks

Jan 05, 2010 | Standard (CRT) Televisions

1 Answer

No raster, no audio, CRT filaments lit, 20KV high voltage, B+ 136V.


most likely you are missing one of the scan derived power sources; most of these sets when HV is present produce some secondary voltages for other things---look at diodes and resistors around the flyback (HV) transformer--if you find an open resistor there--follow it back to the diode that supplies it---also try to check all the smaller voltages from the main power supply

Aug 07, 2009 | Disney DT1900-P 19" TV

1 Answer

Panasonic COLOR CT-27G14A


check Vertical IC out (LA78..) and resistor voltage supply from flyback transformer to this ic. Check the STR main power supply(and resistor near, change value), some times seems good out main board,but in operation not good

May 18, 2008 | Standard (CRT) Televisions

1 Answer

The set goes into a overvoltage mode


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 :)

Mar 11, 2008 | Sony KV-20FS12 20" TV

1 Answer

Tv wont come on


Hi sunny212
1) your tv have it problem in the power regulator you need check
the voltage
should will be 130v no more

2)also check the b+ voltage 180v in the seccion color output
may be is aussent voltage
or open resistor near to flyback transformer

Nov 25, 2007 | Sanyo DS20930 20" TV

6 Answers

Insignia NS-F27C 27" Flat Tube TV


I repaired it!
My Insignia TV set started showing the same problem reported here, after a static discharge sparked when my wife was cleaning the TV with a cloth.
The information provided by bill47 proved to be very useful. I tried to find the data sheet of the large 64 pin IC, TDA973, I found the TDA 9351, which may be from the same family. I measured the voltage at pin 6 and it was approx. 0.2V. I imagined that if I forced that voltage to a higher value the IC would believe that no button is deppressed and so return to normality. From bill47 comments and my measurements of resistance to ground with the TVset off I estimated that a voltage divider was formed with a 3.3K resistor from +3.3V to pin 6 and 180 ohm to pin 6 to ground. In those conditions, I calculated that if I add a 18 ohm resistor from 3.3V to pin 6 I should force the voltage at that pin to 3V. I first tried with a 120 ohm resistor between pin 61 (peripherial power supply in) (+3.3V) and pin 6. This moved the voltage to 1.7V, the failure persisted, but the effect was different, as if another button, located at the rigth of the Input button, was permanently depressed. This showed me that I was in the right trak. I refined my calculations and replaced the 120 ohm resistor to 15 ohm. That raised the voltage at pin 6 to 2.5 V, and solved the problem. The front panel buttons were disabled (except for the Power button), but that is not a problem, I never use them, I always use the remote control. So I can continue enjoying my Insignia TV set! Thank you bill47 and all the other people who posted their comments.

Oct 18, 2007 | Insignia IS 20" TV040919 TV

4 Answers

Tv trouble shooting


whenever any fusible resistance fails means there is a short ckt in tv. failure is mainly due to main filter cap or rectifire diode os switching ckt failure(here as you cleared str.) remember while servicing power supply isolate hor. section for safety purpose.& connect it only after power supply output is ok &after checking parts in hor. ouyput section. if this seems to be ok then go for hor.output ckt failure like hor output,flyback transformer & cap& diodes connected with it.

Oct 02, 2007 | Standard (CRT) Televisions

1 Answer

No power.


Usually, in those Sony sets, a crack developes on a small transformer in the horizontal drive circuit, which causes the horizontal output transistor to short. This immediately shorts out the switching transistors in the power supply and blows the Sony 0.1 ohm resistor fuse. A shorted flyback (high voltage) transformer will also have the same result. The power supply does NOT need to be replaced. The parts should be replaced, the flyback checked and the board resoldered by a qualified tech familiar with Sony sets.

Aug 23, 2007 | Sony KV-32V35 TV

1 Answer

Jvc tv


You need to check the horizontal output transistor first for a short,ift he transistor is good check the diodes and low value resistors of the secondary of the flyback(output trasformer),if all those are ok check the crt board,it has low value resistor for the g2 voltage,if ok you need to go back to power supply and check for a short from each one of the diodes to ground for a posiblwe short.Be careful when measuring voltages and use the correct ground.

Oct 01, 2006 | JVC AV-36F702 36" TV

Not finding what you are looking for?
Standard (CRT) Televisions Logo

Related Topics:

54 people viewed this question

Ask a Question

Usually answered in minutes!

Top Standard (CRT) Televisions Experts

The Knight
The Knight

Level 3 Expert

68368 Answers

matt martin
matt martin

Level 3 Expert

1191 Answers

Donald DCruz
Donald DCruz

Level 3 Expert

17129 Answers

Are you a Standard (CRT) Television Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...