 Posted: Mon Mar 02, 2009 6:46 pm Post subject: |
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| Replace the pump up cap. Usually 100uf@25 vdc near the vertical IC. | |
| Posted: Mon Mar 02, 2009 7:59 am Post subject: |
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| Another common cause for vertical overscan (which in turn can cause clipping in the output stage and then retrace lines) is that the feedback shunt at the "cold" end of the vertical coils is off correct value. Usually, this is a resistor of for example 1 ohm or 2,2 ohm, in some cases it is built up of two parallel resistors and if one of those gets open circuit, you will have this symptom.
If the problem has evolved gradually over a long period of time, then it is probably due to electrolytics, but if the tv worked well and then suddenly got the fault, then it is more probable that it is a resistor that has went open circuit, a bad solder joint or something like that. |
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| Posted: Mon Mar 02, 2009 12:06 am Post subject: |
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| That sounds like "foldover."
Check electrolytics in Vertical output circuit and its power supply(ies). |
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| Posted: Sun Mar 01, 2009 9:27 pm Post subject: Vertical overscan ?? |
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| My parents have a 27PT9015D/37 Philips flat screen crt tv that has what looks like vertical overscan , there are retrace lines about 2 inches down from the top . Please if any one has seen this before or has a schematic any help would be greatly appreciated . Thank you for your time . | |