{"id":3972,"date":"2024-01-08T14:39:52","date_gmt":"2024-01-08T22:39:52","guid":{"rendered":"https:\/\/www.rbdinstruments.com\/blog\/?p=3972"},"modified":"2024-01-08T14:39:54","modified_gmt":"2024-01-08T22:39:54","slug":"model-99-abs-current-preamplifier-no-signal-problem","status":"publish","type":"post","link":"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/","title":{"rendered":"Model 99 ABS Current Preamplifier no signal problem"},"content":{"rendered":"\n<p>The Model 99 Current Preamplifier is used on the older PHI (Physical Electronics) 660 scanning Auger electron spectrometers.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-style-default\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?ssl=1\"><img data-attachment-id=\"3973\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/20240108_134700_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_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=\"20240108_134700_resized\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=584%2C584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized-1024x1024.jpg\" alt=\"99 ABS preamp\" class=\"lazy wp-image-3973\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3973\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/20240108_134700_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_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=\"20240108_134700_resized\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=584%2C584&#038;ssl=1\" alt=\"99 ABS preamp\" class=\"wp-image-3973\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134700_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p>There is a fairly common problem with this design of preamplifier where the input JFET can get damaged from sample arcing which results in a total loss of ABS (absorbed current) image.<\/p>\n\n\n\n<p>The most common solution to this issue is to replace QN2 which is a 2N5546 dual JFET.  These parts are obsolete but readily available on Ebay. You can also find equivalent replacement JFETs such as the EXR461.<\/p>\n\n\n\n<p>To replace QN2, first remove the cover from the 99 ABS preamp.<\/p>\n\n\n\n<p>The picture below shows the location of QN2.  <\/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\/2024\/01\/location.jpg?ssl=1\"><img data-attachment-id=\"3974\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/location\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.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;1&quot;}\" data-image-title=\"location\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=584%2C584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location-1024x1024.jpg\" alt=\"\" class=\"lazy wp-image-3974\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3974\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/location\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.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;1&quot;}\" data-image-title=\"location\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3974\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/location.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p>Use a tweezers to pull up each leg of QN2 as you heat it with a soldering iron and then use a solder sucker or copper braid to remove all the solder from the holes on the circuit board.<\/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\/2024\/01\/20240108_134630_resized.jpg?ssl=1\"><img data-attachment-id=\"3975\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/20240108_134630_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_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=\"20240108_134630_resized\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=584%2C584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized-1024x1024.jpg\" alt=\"\" class=\"lazy wp-image-3975\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3975\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/20240108_134630_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_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=\"20240108_134630_resized\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3975\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p>Note the location of the tab that is on the circuit board and then bend the leads on the replacement 2N5546 so that the leads line up with the holes in the board. Press the 2N5546 down so that the pins are firmly in the holes, then remove the 2N5546 and cut the ends of the leads so that they are shorter.  You only want about 1\/8&#8243; of the leads going into to the holes as otherwise the leads might short to the chassis. <\/p>\n\n\n\n<p>Insert the 2N5546 into the holes and solder the lead wires to the board. <\/p>\n\n\n\n<p>Replacing QN2 will likely restore the ABS image.<\/p>\n\n\n\n<p>The schematic below shows that QN2 is the first thing that sees the input signal and so it makes sense that QN2 would likely be damaged from an arc.  Also, JFETs are susceptible to arc damage more than a lower impedance device such as an op amp.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?ssl=1\"><img data-attachment-id=\"3976\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/20240108_134845_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_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=\"20240108_134845_resized\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=584%2C584&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized-1024x1024.jpg\" alt=\"\" class=\"lazy wp-image-3976\" style=\"aspect-ratio:1;width:614px;height:auto\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3976\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/20240108_134845_resized\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_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=\"20240108_134845_resized\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?fit=584%2C584&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"584\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=584%2C584&#038;ssl=1\" alt=\"\" class=\"wp-image-3976\" style=\"aspect-ratio:1;width:614px;height:auto\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?w=1512&amp;ssl=1 1512w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134845_resized.jpg?w=1168&amp;ssl=1 1168w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p>For help with repairs or maintenance on your PHI 660 (or other older PHI surface analysis systems) please contact RBD Instruments here &#8211; <a href=\"https:\/\/rbdinstruments.com\/contact.html\">https:\/\/rbdinstruments.com\/contact.html<\/a><\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>How to repair a 99 ABS preamp <a href=\"https:\/\/www.rbdinstruments.com\/blog\/model-99-abs-current-preamplifier-no-signal-problem\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":3975,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","footnotes":"","jetpack_publicize_message":"How to repair a 99 ABS preamp that is not giving an image. ","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[162],"tags":[441,438,439,440],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/01\/20240108_134630_resized.jpg?fit=1512%2C1512&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p2DEXo-124","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":1228,"url":"https:\/\/www.rbdinstruments.com\/blog\/test-procedure-phi-vf-preamplifiers\/","url_meta":{"origin":3972,"position":0},"title":"Test procedure for PHI V\/F preamplifiers","author":"Randy","date":"October 20, 2014","format":false,"excerpt":"Overview: Most of the older PHI AES systems use a voltage to frequency converter (V\/F) to convert the electron multiplier auger signal output from a small current into a frequency so that the computer can count the signal. At the time these systems were designed, this was a more cost\u2026","rel":"","context":"In &quot;General Optics and Vacuum&quot;","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"preamp-96A-col-and-L2","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2014\/10\/preamp-96A-col-and-L2.png?fit=417%2C371&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]},{"id":860,"url":"https:\/\/www.rbdinstruments.com\/blog\/how-to-test-a-97-sed-preamplifier\/","url_meta":{"origin":3972,"position":1},"title":"How to test a 97 SED preamplifier","author":"Randy","date":"November 8, 2013","format":false,"excerpt":"Older PHI scanning auger systems use the model 97 SED preamplifier to obtain secondary electron images. Occasionally you will not be able to get a TV image on your scanning auger system but are not sure what the problem is. This post will explain how to test the 97 SED\u2026","rel":"","context":"In &quot;Operation and Calibration Procedures&quot;","block_context":{"text":"Operation and Calibration Procedures","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/operation-and-calibration-procedures\/"},"img":{"alt_text":"97-sed-col-tab","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2013\/11\/97-sed-col-tab.jpg?fit=401%2C266&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]},{"id":1779,"url":"https:\/\/www.rbdinstruments.com\/blog\/72-100-voltage\/","url_meta":{"origin":3972,"position":2},"title":"72-100 voltage","author":"Randy","date":"June 2, 2016","format":false,"excerpt":"I recently encountered an unusual problem on two different 660 scanning auger systems within a period of a few months where the 72-100 multiplier voltage would drop off after a period of time. On one system the 97 SED preamp would fail after a few minutes of warm up time,\u2026","rel":"","context":"In &quot;Operation and Calibration Procedures&quot;","block_context":{"text":"Operation and Calibration Procedures","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/operation-and-calibration-procedures\/"},"img":{"alt_text":"72-100 mother board","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2016\/06\/72-100-mother-board.jpg?fit=774%2C1032&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2016\/06\/72-100-mother-board.jpg?fit=774%2C1032&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2016\/06\/72-100-mother-board.jpg?fit=774%2C1032&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":1794,"url":"https:\/\/www.rbdinstruments.com\/blog\/obsolete-phi-units\/","url_meta":{"origin":3972,"position":3},"title":"Obsolete PHI units","author":"Randy","date":"July 25, 2016","format":false,"excerpt":"Obsolete PHI units As many of you may know, RBD Instruments has been providing repair services and parts for old Physical Electronics (PHI) surface analysis systems and components for over 26 years. In fact, some of the electronic and optic units that we work on are over 45 years old!\u2026","rel":"","context":"In &quot;Miscellaneous&quot;","block_context":{"text":"Miscellaneous","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/miscellaneous\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2016\/07\/surface-analysis.png?fit=225%2C225&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]},{"id":4064,"url":"https:\/\/www.rbdinstruments.com\/blog\/a-numbers-for-phi-units\/","url_meta":{"origin":3972,"position":4},"title":"&#8220;A&#8221; Numbers for PHI units","author":"Randy","date":"September 9, 2024","format":false,"excerpt":"A numbers for older PHI surface analysis systems control units.","rel":"","context":"In &quot;General Optics and Vacuum&quot;","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/09\/32-150-A116.jpg?fit=1200%2C540&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/09\/32-150-A116.jpg?fit=1200%2C540&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/09\/32-150-A116.jpg?fit=1200%2C540&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/09\/32-150-A116.jpg?fit=1200%2C540&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":231,"url":"https:\/\/www.rbdinstruments.com\/blog\/how-to-align-the-04-303-ion-gun\/","url_meta":{"origin":3972,"position":5},"title":"How to align the 04-303 ion gun","author":"Randy","date":"November 29, 2012","format":false,"excerpt":"This post explains how to align the Physical Electronics 04-303 ion gun typically found on PHI Auger electron spectroscopy and X-ray photoelectron spectroscopy systems. The alignment principles explained here will apply to just about any surface analysis ion source. First, here is a video that explains all of the alignment\u2026","rel":"","context":"In &quot;Ion Sources&quot;","block_context":{"text":"Ion Sources","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/ion-sources\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3972"}],"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=3972"}],"version-history":[{"count":1,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3972\/revisions"}],"predecessor-version":[{"id":3977,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3972\/revisions\/3977"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/media\/3975"}],"wp:attachment":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/media?parent=3972"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/categories?post=3972"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/tags?post=3972"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}