{"id":3643,"date":"2022-11-15T07:30:00","date_gmt":"2022-11-15T15:30:00","guid":{"rendered":"https:\/\/www.rbdinstruments.com\/blog\/?p=3643"},"modified":"2023-12-13T14:40:31","modified_gmt":"2023-12-13T22:40:31","slug":"transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components","status":"publish","type":"post","link":"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/","title":{"rendered":"Transistor Heat Sink Fatigue"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Some of the older PHI electronic units have a type of heat sink with a built-in spring tab (shown in the picture below) that forces the back of a transistor into the heat sink.&nbsp; Over time, the spring tab can lose tension (most likely due to heat induced metal fatigue) and then the transistor no longer connects to the heat sink, eventually resulting in the transistor failing due to overheating.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3644\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/spring-tab\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Spring-tab\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg\" alt=\"\" class=\"lazy wp-image-3644\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3644\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/spring-tab\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Spring-tab\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3644\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Spring-tab.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">For units such as the 32-100 Electron Multiplier Supply, overheated transistors are often the cause of multiplier voltage output problems.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For this blog post we will look at a 32-100 electron multiplier supply with no output on the CMA high voltage output.&nbsp;The problem was isolated to a bad TIP120 transistor which shorted out and melted because the back of the transistor separated from the heat sink over time.   <\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3645\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/tip-120-transistor-in-hv-circuit\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?fit=1094%2C714&amp;ssl=1\" data-orig-size=\"1094,714\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"TIP-120-transistor-in-HV-circuit\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?fit=584%2C381&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit-1024x668.jpg\" alt=\"\" class=\"lazy wp-image-3645\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"381\" data-attachment-id=\"3645\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/tip-120-transistor-in-hv-circuit\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?fit=1094%2C714&amp;ssl=1\" data-orig-size=\"1094,714\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"TIP-120-transistor-in-HV-circuit\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?fit=584%2C381&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?resize=584%2C381&#038;ssl=1\" alt=\"\" class=\"wp-image-3645\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?resize=1024%2C668&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?resize=300%2C196&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?resize=768%2C501&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?resize=460%2C300&amp;ssl=1 460w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/TIP-120-transistor-in-HV-circuit.jpg?w=1094&amp;ssl=1 1094w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">In addition to replacing the TIP120 transistor, we also modified the heat sink to ensure a good contact with the transistor.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To modify the heat sink, you need to first remove the defective transistor and then remove the heat sink.&nbsp; You will need a hot soldering iron as the heat sink has enough mass that it will drain away some of the heat from the soldering iron.&nbsp;&nbsp; You can use a solder sucker or some solder braid to remove the solder from the heat sink contacts.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3646\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/remove-heat-sink\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Remove-heat-sink\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg\" alt=\"\" class=\"lazy wp-image-3646\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3646\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/remove-heat-sink\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Remove-heat-sink\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3646\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Remove-heat-sink.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Once the heat sink as been removed, break off the spring tab.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3648\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/20221102_164629_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?fit=1512%2C1512&amp;ssl=1\" data-orig-size=\"1512,1512\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"20221102_164629_resized\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized-1024x1024.jpg\" alt=\"\" class=\"lazy wp-image-3648\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3648\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/20221102_164629_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?fit=1512%2C1512&amp;ssl=1\" data-orig-size=\"1512,1512\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"20221102_164629_resized\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3648\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164629_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3649\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/20221102_164636_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?fit=1512%2C1512&amp;ssl=1\" data-orig-size=\"1512,1512\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"20221102_164636_resized\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized-1024x1024.jpg\" alt=\"\" class=\"lazy wp-image-3649\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3649\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/20221102_164636_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?fit=1512%2C1512&amp;ssl=1\" data-orig-size=\"1512,1512\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"20221102_164636_resized\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3649\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/20221102_164636_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Next, drill a small hole in the back of the heat sink where the indent is located. We used a 9\/64&#8243; drill bit since we needed to clear a 6-32 screw and lock nut.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3647\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/drill-hole-here\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Drill-hole-here\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg\" alt=\"\" class=\"lazy wp-image-3647\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3647\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/drill-hole-here\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Drill-hole-here\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3647\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/Drill-hole-here.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"> Put some heat sink compound or conductive tape on the back of the replacement transistor.&nbsp; This is necessary to ensure good thermal transfer from the transistor to the heat sink.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3651\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/heat-sink-compound\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"heat-sink-compound\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg\" alt=\"\" class=\"lazy wp-image-3651\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3651\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/heat-sink-compound\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"heat-sink-compound\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3651\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/heat-sink-compound.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Use a screw and lock nut to attach the transistor to the heat sink.&nbsp; Make sure that the transistor is centered in the heat sink.&nbsp;&nbsp; In this case we also added another small heat sink to the back of the original heat sink to add some additional cooling for the transistor.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3652\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/centered-tip120\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"centered-TIP120\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg\" alt=\"\" class=\"lazy wp-image-3652\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3652\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/centered-tip120\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"centered-TIP120\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3652\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/centered-TIP120.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3653\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/extra-heat-sink\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"extra-heat-sink\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg\" alt=\"\" class=\"lazy wp-image-3653\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3653\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/extra-heat-sink\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"extra-heat-sink\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3653\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/extra-heat-sink.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Next, insert the transistor leads into the holes on the board and insert the heat sink into the larger holes in the board.&nbsp;&nbsp; Solder the heat sink and the transistor leads. &nbsp;Cut the excess leads from the transistor and remove any excess flux from the board.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3654\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/new-transistor-with-modified-heat-sink\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"new-transistor-with-modified-heat-sink\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg\" alt=\"\" class=\"lazy wp-image-3654\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3654\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/new-transistor-with-modified-heat-sink\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"new-transistor-with-modified-heat-sink\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3654\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Now that we have replaced the transistor and improved the transistor to heat sink contact, the 32-100 should perform well for many years.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Since we were replacing the one defective TIP120 transistor, we also replaced the one for the SED supply as well (and modified its heat sink) as a preventive measure. &nbsp;In this case we could not add the extra small heat sink due to a tight clearance to the nearby transformer. Even so, the improved contact to the heat sink will provide improved heat transfer from the transistor and result in improved reliability.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?ssl=1\"><img data-recalc-dims=\"1\" decoding=\"async\" data-attachment-id=\"3655\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/sed-tip120\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"SED-TIP120\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?w=584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg\" alt=\"\" class=\"lazy wp-image-3655\"\/><noscript><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"584\" height=\"584\" data-attachment-id=\"3655\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/sed-tip120\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?fit=756%2C756&amp;ssl=1\" data-orig-size=\"756,756\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"SED-TIP120\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?fit=584%2C584&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3655\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?w=756&amp;ssl=1 756w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/SED-TIP120.jpg?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 584px) 100vw, 584px\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Need help with your older PHI (Physical Electronics) surface analysis system electronics (or optics)?  <a href=\"https:\/\/rbdinstruments.com\/contact.html\" data-type=\"link\" data-id=\"https:\/\/rbdinstruments.com\/contact.html\" target=\"_blank\" rel=\"noreferrer noopener\">Contact us for more information<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Method to improve contact to transistor heat sink in older PHI electronic units <a href=\"https:\/\/www.rbdinstruments.com\/blog\/transistor-heat-sink-fatigue-on-older-phi-surface-analysis-electronic-components\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":3654,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[166],"tags":[402,400,401],"class_list":["post-3643","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-miscellaneous","tag-32-100-no-high-voltage","tag-transistor-failure","tag-transistor-heat-sink"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/11\/new-transistor-with-modified-heat-sink.jpg?fit=756%2C756&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p2DEXo-WL","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3643","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/comments?post=3643"}],"version-history":[{"count":1,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3643\/revisions"}],"predecessor-version":[{"id":3945,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3643\/revisions\/3945"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/media\/3654"}],"wp:attachment":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/media?parent=3643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/categories?post=3643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/tags?post=3643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}