{"id":1006,"date":"2016-04-03T18:23:22","date_gmt":"2016-04-03T23:23:22","guid":{"rendered":"http:\/\/paulcarbone.com\/blog\/?p=1006"},"modified":"2016-04-04T13:29:43","modified_gmt":"2016-04-04T18:29:43","slug":"tektronix-tm-503-repair","status":"publish","type":"post","link":"https:\/\/paulcarbone.com\/blog\/tektronix-tm-503-repair\/","title":{"rendered":"Tektronix TM-503 repair"},"content":{"rendered":"

The third bay of my recently acquired TM-503 mainframe ate two plug-ins, releasing their magic smoke.\u00a0 The it didn’t do this to the module that came originally installed in the 3rd bay, and here’s why:<\/p>\n

The mainframe has two power transistors for each bay that are wired to the edge connectors.\u00a0 They’re meant to be used by the plugin’s power supply.\u00a0 The DM-502 that was originally in the 3rd bay didn’t actually use these transistors, but the DC504 and FG501 did.\u00a0 The photo below shows 3 of these transistors.\u00a0 The one on the far right is for the center bay, and it has a mica disc insulating it from the chassis.\u00a0 The two on the left did not have those mica insulators.\u00a0 Some knucklehead that replaced the left-most transistor (center one removed by me), forgot to re-install the mica disc, and I found one floating around the inside when I opened it up.\u00a0 This meant that one of the pins was shorting to ground, and he was only lucky not to get bit because of the plug-in he was using.<\/p>\n

You’ll also see a 5v regulator bodged onto the unit, it’s output has been snipped.<\/p>\n

\"IMG_5775.JPG\"<\/a><\/p>\n

Here’s the damage caused by the error:<\/p>\n

A blown trace on the DC504\"IMG_5776.JPG\"<\/a><\/p>\n

And one of two blown resistors on the FG501.\u00a0 I’ll have to order replacements, they’re .27\u03a9, of some reasonable wattage.\u00a0 \"IMG_5777.JPG\"<\/a><\/p>\n

The trace repaired:
\n\"IMG_5781.JPG\"<\/a><\/p>\n

And the mica replaced:
\n\"IMG_5780.JPG\"<\/a><\/p>\n

DC504 is back to life. It’s not the greatest counter, but it claims it’ll go up to 80Mhz.
\n\"IMG_5782.JPG\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

The third bay of my recently acquired TM-503 mainframe ate two plug-ins, releasing their magic smoke.\u00a0 The it didn’t do this to the module that came originally installed in the 3rd bay, and here’s why: The mainframe has two power … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[26],"tags":[52,53,51,27],"table_tags":[],"_links":{"self":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/1006"}],"collection":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/comments?post=1006"}],"version-history":[{"count":1,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/1006\/revisions"}],"predecessor-version":[{"id":1007,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/1006\/revisions\/1007"}],"wp:attachment":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/media?parent=1006"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/categories?post=1006"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/tags?post=1006"},{"taxonomy":"table_tags","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/table_tags?post=1006"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}