{"id":448,"date":"2025-12-07T16:33:52","date_gmt":"2025-12-07T16:33:52","guid":{"rendered":"https:\/\/darylwhite.net\/?p=448"},"modified":"2025-12-07T16:33:52","modified_gmt":"2025-12-07T16:33:52","slug":"1989-jaguar-xjs-v12-odometer-repair","status":"publish","type":"post","link":"https:\/\/darylwhite.net\/index.php\/2025\/12\/07\/1989-jaguar-xjs-v12-odometer-repair\/","title":{"rendered":"1989 Jaguar XJS V12 Odometer Repair"},"content":{"rendered":"
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The odometer stopped working in my XJS so I took apart the instrument cluster to investigate futher. It’s an electromechanical system that starts with a VR sensor mounted to the rear differential before being signal proccessed into something that can turn a motor and the odometer gears.<\/p>\n\n\n

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Using a bench top power supply and signal generator I managed to revive the driving motor but it was intermittent and jerky in operation. I’m not sure what type of motor it is but I flushed it with electrical switch cleaner and this improved things. <\/p>\n\n\n

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The circuit board has been discussed on other forums as it’s a similar design to the rev counter. Its a metal\/ceramic substrate with thick film resistors and a mixture of surface mount and through hole mount components which I thought impressive for 1989.
The IC’s are a HEF4024B 7-stage binary counter and a TI MIC2\/2 which is a custom part equivalent to a SAK215 pulse shaper IC. Other components on the board are various smt transistors including 4 of them arranged in a H-bridge configuration for driving the motor.<\/p>\n\n\n\n

Here are some interesting links that discuss the speedo\/odometer circuit and the similarities with the rev counter.<\/p>\n\n\n\n

https:\/\/forums.jag-lovers.com\/t\/tachometer-rebuild\/386257\/12<\/a>
https:\/\/forums.jag-lovers.com\/t\/newcomer-xjs-v12-1988-and-some-problems-start-but-no-crank\/395748\/73<\/a><\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

The odometer stopped working in my XJS so I took apart the instrument cluster to investigate futher. It’s an electromechanical system that starts with a VR sensor mounted to the rear differential before being signal proccessed into something that can turn a motor and the odometer gears. Using a bench top power supply and signal […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-448","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/posts\/448","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/comments?post=448"}],"version-history":[{"count":4,"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/posts\/448\/revisions"}],"predecessor-version":[{"id":459,"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/posts\/448\/revisions\/459"}],"wp:attachment":[{"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/media?parent=448"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/categories?post=448"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/darylwhite.net\/index.php\/wp-json\/wp\/v2\/tags?post=448"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}