|
|
<p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(112, 48, 160); box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">1.电阻损坏的特点</strong></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"> </span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">电阻是电器设备中数量最多的元件，但不是损坏率最高的元件。电阻损坏以开路最常见，阻值变大较少见，阻值变小十分少见。常见的有碳膜电阻、金属膜电阻、线绕电阻和保险电阻几种。前两种电阻应用最广，其损坏的特点一是低阻值(100Ω以下)和高阻值(100kΩ以上)的损坏率较高，中间阻值(如几百欧到几十千欧)的极少损坏;二是低阻值电阻损坏时往往是烧焦发黑，很容易发现，而高阻值电阻损坏时很少有痕迹。线绕电阻一般用作大电流限流，阻值不大。圆柱形线绕电阻烧坏时有的会发黑或表面爆皮、裂纹，有的没有痕迹。水泥电阻是线绕电阻的一种，烧坏时可能会断裂，否则也没有可见痕迹。保险电阻烧坏时有的表面会炸掉一块皮，有的也没有什么痕迹，但绝不会烧焦发黑。根据以上特点，在检查电阻时可有所侧重，快速找出损坏的电阻。</span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><img src="http://mmbiz.qpic.cn/mmbiz/n9BCHWJuRJdzyh5Fp34xlCVWbiaUmtrN1yiceibLDdtNOVKXATXs54cHQU8qmuiaYKmddeRdECbALhP8UbNDBvhL8A/0?wx_fmt=png?wx_fmt=png" data-ratio="0.05740181268882175" data-w="331" width="330.9895935058594px" width="330.9895935058594px" src="http://mmbiz.qpic.cn/mmbiz/n9BCHWJuRJdzyh5Fp34xlCVWbiaUmtrN1yiceibLDdtNOVKXATXs54cHQU8qmuiaYKmddeRdECbALhP8UbNDBvhL8A/0?wx_fmt=png?wx_fmt=png?tp=webp&wxfrom=5" style="margin: 0px; padding: 0px; color: rgb(68, 68, 68); font-family: 微软雅黑; font-size: 13.043478965759277px; line-height: 23.98097801208496px; border: 0px; box-sizing: border-box !important; word-wrap: break-word !important; width: 330.9895935058594px !important; visibility: visible !important;" /></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(112, 48, 160); box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">2.电解电容损坏的特点</strong></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"> </span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">电解电容在电器设备中的用量很大，故障率很高。电解电容损坏有以下几种表现：一是完全失去容量或容量变小;二是轻微或严重漏电;三是失去容量或容量变小兼有漏电。查找损坏的电解电容方法有：</span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"> </span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">(1)看：有的电容损坏时会漏液，电容下面的电路板表面甚至电容外表都会有一层油渍，这种电容绝对不能再用;有的电容损坏后会鼓起，这种电容也不能继续使用;</span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"> </span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">(2)摸：开机后有些漏电严重的电解电容会发热，用手指触摸时甚至会烫手，这种电容必须更换;</span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"> </span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">(3)电解电容内部有电解液，长时间烘烤会使电解液变干，导致电容量减小，所以要重点检查散热片及大功率元器件附近的电容，离其越近，损坏的可能性就越大。</span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(112, 48, 160); box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">3.二、三极管等半导体器件损坏的特点</strong></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"> </span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">二、三极管的损坏一般是PN结击穿或开路，其中以击穿短路居多。此外还有两种损坏表现：一是热稳定性变差，表现为开机时正常，工作一段时间后，发生软击穿;另一种是PN结的特性变差，用万用表R×1k测，各PN结均正常，但上机后不能正常工作，如果用R×10或R×1低量程档测，就会发现其PN结正向阻值比正常值大。测量二、三极管可以用指针万用表在路测量，较准确的方法是：将万用表置R×10或R×1档(一般用R×10档，不明显时再用R×1档)在路测二、三极管的PN结正、反向电阻，如果正向电阻不太大(相对正常值)，反向电阻足够大(相对正向值)，表明该PN结正常，反之就值得怀疑，需焊下后再测。这是因为一般电路的二、三极管外围电阻大多在几百、几千欧以上，用万用表低阻值档在路测量，可以基本忽略外围电阻对PN结电阻的影响。</span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"></span></p><p style="margin-top: 0px; margin-bottom: 0px; padding: 0px; max-width: 100%; word-wrap: normal; min-height: 1em; white-space: normal; border: 0px; color: rgb(68, 68, 68); font-family: 微软雅黑; font-size: 13.333333969116211px; line-height: 1.5em; text-align: center; background-color: rgb(255, 255, 255); box-sizing: border-box !important;"><img src="http://mmbiz.qpic.cn/mmbiz/n9BCHWJuRJdzyh5Fp34xlCVWbiaUmtrN1yiceibLDdtNOVKXATXs54cHQU8qmuiaYKmddeRdECbALhP8UbNDBvhL8A/0?wx_fmt=png?wx_fmt=png" data-ratio="0.05740181268882175" data-w="331" width="330.9895935058594px" width="330.9895935058594px" src="http://mmbiz.qpic.cn/mmbiz/n9BCHWJuRJdzyh5Fp34xlCVWbiaUmtrN1yiceibLDdtNOVKXATXs54cHQU8qmuiaYKmddeRdECbALhP8UbNDBvhL8A/0?wx_fmt=png?wx_fmt=png?tp=webp&wxfrom=5" style="margin: 0px; padding: 0px; border: 0px; box-sizing: border-box !important; word-wrap: break-word !important; width: 330.9895935058594px !important; visibility: visible !important;" /></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(112, 48, 160); box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">4.集成电路损坏的特点</strong></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"> </span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;">集成电路内部结构复杂，功能很多，任何一部分损坏都无法正常工作。集成电路的损坏也有两种：彻底损坏、热稳定性不良。彻底损坏时，可将其拆下，与正常同型号集成电路对比测其每一引脚对地的正、反向电阻，总能找到其中一只或几只引脚阻值异常。对热稳定性差的，可以在设备工作时，用无水酒精冷却被怀疑的集成电路，如果故障发生时间推迟或不再发生故障，即可判定。通常只能更换新集成电路来排除。</span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><br /></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="white-space: pre-wrap; color: rgb(0, 176, 240); font-size: 18px; font-family: 微软雅黑; line-height: 26px; margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><span style="margin: 0px; padding: 0px; max-width: 100%; font-size: 14px; box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><span style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(227, 108, 9); box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(255, 0, 0); font-size: 18px; box-sizing: border-box !important; word-wrap: break-word !important;">点击阅读原文</strong></span></strong></span></strong></span></p><p style=""><span style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="white-space: pre-wrap; color: rgb(0, 176, 240); font-size: 18px; font-family: 微软雅黑; line-height: 26px; margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><span style="margin: 0px; padding: 0px; max-width: 100%; font-size: 14px; box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><span style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(227, 108, 9); box-sizing: border-box !important; word-wrap: break-word !important;"><strong style="margin: 0px; padding: 0px; max-width: 100%; color: rgb(255, 0, 0); font-size: 18px; box-sizing: border-box !important; word-wrap: break-word !important;"><br /></strong></span></strong></span></strong></span></p><p><span style="background-color: rgb(255, 255, 255); color: rgb(0, 112, 192);"><strong><span style="background-color: rgb(255, 255, 255); text-decoration: underline;"></span></strong></span></p><p style="white-space: normal;"><strong><span style="color: rgb(0, 112, 192);">关于成立中国总公司 通知</span></strong></p><p style="white-space: normal;"><strong style="font-size: 16px;"><span style="color: rgb(0, 112, 192);">《我的足迹，我的路》--记医疗器械售后服务工程师的一天</span></strong><br /></p><h4 style="white-space: normal;"><strong>透析机维修你必知的!</strong></h4><h4 style="white-space: normal;"><strong style="color: rgb(0, 112, 192);">Linux常用命令大全</strong></h4><hr /><p><br /></p><p style="white-space: normal; text-align: center; line-height: 1.75em;"><strong style="font-size: 14px; line-height: 21px; color: rgb(255, 255, 255); font-family: arial, helvetica, sans-serif; margin: 0px; padding: 0px; max-width: 100%; box-sizing: border-box !important; word-wrap: break-word !important;"><span class="bkcolor" style="margin: 0px 8px 0px 0px; padding: 4px 10px; max-width: 100%; border-top-left-radius: 5px; border-top-right-radius: 5px; border-bottom-left-radius: 5px; border-bottom-right-radius: 5px; background-color: rgb(191, 0, 0); box-sizing: border-box !important; word-wrap: break-word !important;"></span></strong><br /></p><p style="white-space: normal; text-align: center; line-height: 1.75em;"><strong><span style="line-height: 2em; color: rgb(255, 0, 0);">ID: </span></strong></p><p style="white-space: normal; text-align: center; line-height: 1.75em;"><span style="font-size: 14px;">最具人气的医疗器械维修新媒体平台</span></p><p style="white-space: normal; text-align: center; line-height: 1.75em;"><span style="font-size: 11px;"><span style="font-size: 14px;">分享医疗器械前沿动态、医疗器械维修经验</span> </span></p><p style="white-space: normal; text-align: center; line-height: 1.75em;"><span style="font-size: 14px;">医疗器械维修人自己的交流平台</span></p><p style="white-space: normal; text-align: center; line-height: 1.75em;"><strong><span style="color: rgb(127, 127, 127); font-size: 11px;">加群主微信 </span></strong><strong><span style="color: rgb(149, 55, 52); font-size: 11px;">shanying916</span></strong><strong><span style="color: rgb(127, 127, 127);"><span style="font-size: 11px;"><span style="color: rgb(149, 55, 52); font-size: 11px;"></span> </span><span style="font-size: 12px;">与更多行业从业人员互动交流</span></span></strong><strong style="line-height: 1.75em; font-size: 16px;"><span style="color: rgb(127, 127, 127); font-size: 12px;"> </span></strong></p><p style="white-space: normal; line-height: 1.75em; text-align: center;"><strong><span style="color: rgb(127, 127, 127);"><span style="font-size: 12px;"><img data-s="300,640" data-type="jpeg" src="http://mmbiz.qpic.cn/mmbiz/A1DicCH9Vl6MoypciaNOibiaxmVLk8eA6ibKL14uWjKsZwrWboQYKTfXqPicXycwL1icfia1pAG0VzlTX3MRR4FPV0ZtZA/0?wx_fmt=jpeg" data-ratio="1.0136054421768708" data-w="147" /></span></span></strong></p>
|
|
发表于 2020-10-21 13:23:30