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标题:
联机上电有显示画面,但存在枕形失真
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作者:
兴宁528
时间:
2012/1/18 18:01
标题:
联机上电有显示画面,但存在枕形失真
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<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN>分析:从故障现象看,故障出在枕形校正电路。</SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN>处理:首先R701、VR702,但调整无效,检查VR701和VR702电位器本身正常,C701和C702两电容电压,Q701也正常。在排除外围电路故障的情况下,估计故障出在U701(LM358)上,在线测量U701芯片如下表:</SPAN></P>
<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN>U701在线测量数据:</SPAN></P>
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<P class=MsoNormal> <SPAN lang=EN-US><?XML:NAMESPACE PREFIX = O /><O:P> </O:P></SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: windowtext 0.5pt solid; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal>故障值(<SPAN lang=EN-US>V)</SPAN></P></TD>
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<P class=MsoNormal>正常值(<SPAN lang=EN-US>V)</SPAN></P></TD></TR>
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<P class=MsoNormal><SPAN lang=EN-US>1</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>7.5</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>7.5</SPAN></P></TD></TR>
<TR style="HEIGHT: 15.75pt">
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 108pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=144>
<P class=MsoNormal><SPAN lang=EN-US>2</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>7.5</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>7.5</SPAN></P></TD></TR>
<TR style="HEIGHT: 15.75pt">
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 108pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=144>
<P class=MsoNormal><SPAN lang=EN-US>3</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>1.6</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>7.5</SPAN></P></TD></TR>
<TR style="HEIGHT: 15.75pt">
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 108pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=144>
<P class=MsoNormal><SPAN lang=EN-US>4</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>0</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>0</SPAN></P></TD></TR>
<TR style="HEIGHT: 15.75pt">
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 108pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=144>
<P class=MsoNormal><SPAN lang=EN-US>5</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>7.0</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>7.0</SPAN></P></TD></TR>
<TR style="HEIGHT: 15.75pt">
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 108pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=144>
<P class=MsoNormal><SPAN lang=EN-US>6</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>0</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>0</SPAN></P></TD></TR>
<TR style="HEIGHT: 15.75pt">
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 108pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=144>
<P class=MsoNormal><SPAN lang=EN-US>7</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>9.4</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>9.4</SPAN></P></TD></TR>
<TR style="HEIGHT: 15.75pt">
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 0.5pt solid; WIDTH: 108pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=144>
<P class=MsoNormal><SPAN lang=EN-US>8</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 155.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=207>
<P class=MsoNormal><SPAN lang=EN-US>22</SPAN></P></TD>
<TD style="BORDER-RIGHT: windowtext 0.5pt solid; PADDING-RIGHT: 5.4pt; BORDER-TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: medium none; WIDTH: 152.25pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 0.5pt solid; HEIGHT: 15.75pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt" vAlign=top width=203>
<P class=MsoNormal><SPAN lang=EN-US>22</SPAN></P></TD></TR></TBODY></TABLE>
<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN>从表中数据看,U<SUB>701</SUB>第3脚电压偏离正常值,更换U701后,联机上电,调用测试图显示画面,微调VR<SUB>701</SUB>、VR<SUB>702</SUB>,画面显示正常,故障排除。</SPAN></P>
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<P class=MsoNormal><SPAN lang=EN-US> <O:P> </O:P></SPAN></P>
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