 Posted: Wed May 14, 2008 2:03 pm Post subject: |
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| I resoldered the whole board last night and retested - just to make sure. on IC801 i now have 13.4v on pin7(VCC) still only 0.8v on pin 6(schematic shows 4V) I dont have a scope, or know anyone that has one so I think I will have to call it a day. It is a shame because it is a nice TV, but it is now just taking up too much room so it will have to go. Thanks again for all your guidance, I really appreciate it. Cheers Steve |
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| Posted: Wed May 14, 2008 1:42 pm Post subject: |
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| check the drive waveform from the ic to the fet, unfortunately you will need an oscilloscope to do this, if the drive is not continous before the set goes into standby the set may be shutting down due to a feedback problem via the optocoupler and/or over current protection. | |
| Posted: Wed May 14, 2008 10:57 am Post subject: |
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| Any other suggestions before it goes to landfill? Cheers Steve  |
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| Posted: Thu May 08, 2008 5:51 pm Post subject: |
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| Thanks again Gary. I have checked q803/4 seem ok, no shorts. All resistors seem to be within tolerance. I dropped the circuit board when putting the tv back together so thought i had better check for any damage. Now the time it takes to go back into standby has increased from 2 to 5 seconds. I rechecked the voltages on the new IC801 pin1 1.5v pin2 .49v pin3 .41v pin4 .2v pin5 .17v pin6 .81v pin7 13.35v pin8 2.67v pin9 4.73v Also, should I expect any voltage from S1 and S2 of T802? I tested at Q849 but got no voltage at all. Should I give up or is there still hope? Cheers Steve |
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| Posted: Thu May 08, 2008 3:45 pm Post subject: |
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| q804 and q803 have been known to cause problems, check all resistors in psu, especially the high value ones | |
| Posted: Thu May 08, 2008 1:06 pm Post subject: |
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| I have just replaced IC801. No Change Steve |
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| Posted: Wed May 07, 2008 3:20 pm Post subject: |
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| replace the ic | |
| Posted: Wed May 07, 2008 2:38 pm Post subject: |
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| also Q801 S 0v G 0.8v D 335v |
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| Posted: Wed May 07, 2008 1:33 pm Post subject: |
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| OOPS!! Ok this time for real. IC801 pin1 1.8v pin2 0.6v pin3 0.4v pin4 0.3v pin5 0.25v pin6 1.1v pin7 11.3v pin8 1.1v pin9 5.5v T802 P1 335v P2 335v V1 0v V2 0v I am presuming i need a scope to test waveform on pin6 of IC801? Cheers Steve Damn this electrickery! |
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| Posted: Wed May 07, 2008 8:28 am Post subject: |
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| when testing on the primary side of the psu DO NOT use the chassis earth, you should use the the negative pin of the bridge rectifier, this is because the set uses an isolated chassis design with the psu transformer t801 acting as the isolator. | |