Tektronix TM-500 series latch repair - Page 1
Forum section: electronics / repair

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 23, 2016, 12:29:26 am
content: I have a couple of these TM-500 series modules with the latch tab broken off. I am sure others have encountered this, though a search of the forum didn't find anything on the topic. For the particular ones I am currently working the Tektonix part number is 366-1851-01, but that knowledge is next to useless as no one I found had any in stock. So I came up with a cheap and easy replacement. Might not be good for commercial work, but more than adequate for us hobby folk.The latch breaks because these modules require substantial force to remove, more than the release tab can support. The best technique is to gently pull the tab to release the catch, and while holding the tab out tug and pull on other parts of the module to back it out of the bay. It often requires three or more hands or some other fancy work. It helps if the frame is screwed to the bench. Not one of Tektronix finest designs in my opinion.The fix is simple.The first step is to get the module out of the bay. This is done by removing the screw under the latch knob. The latch is now loose and the module can be removed (easier since you don't have to hold the release knob out). Removing the aluminum cover on the side of the module will let you see the latch and latch retaining lever. Pay attention to how they are assembled as there are several wrong ways to put it back together. The second picture below will help with this.The latch knob (Tektronix nomenclature) is the little Tektronix logoed button with a rectangular extension which has notches cut into it to slot into the Latch Release Bar (again Tektronix nomenclature). This functionality can be replaced with the end of a nylon wire tie trimmed appropriately. The first picture shows the trimmed wire tie.I cut the tie to approximate size and shape with a sharp knife, and then test fit in the Latch Release Bar, trimming as required to get a good fit. Overall length is not critical, it merely needs to be long enough to reach out of the module. Too long will not be pretty, but it will be functional. The critical parts are the distance from the end of the wire tie to the near side of the notches and the width of the notches. The closeup in picture one shows that the edges don't have to be perfect.For re-assembly you insert the knob through the front of the module and attach the latch release bar. Then you insert the latch from the bottom of the module and slide it over the end of the latch release bar. After arranging the components in their operating position the latch is screwed to the front panel with the screw that was removed in the very first step.The last picture shows what the complete job looks like. People looking for more perfection could create an over mold for this part that would duplicate the original shape, but I just need the functionality.

author: Martin.M
author_rank: Frequent Contributor
timestamp: November 26, 2016, 06:23:01 pm
content: Plugins of the 500 Series (Classic Tek) have no latch, they are handled by the fixing screw.I Think you have there a 5000 Series - or 7000 series Tek scope.greetingsMartin

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 26, 2016, 06:31:48 pm
content: Different 500 series. These are plug ins for the TM-500 series power frames.The following link gives a summary of the various functions that could be assembled. As a young engineer I really lusted after these for my home lab, but they were priced out of my range.http://www.barrytech.com/tektronix/tektm500/tektm500pluginsumm.html

author: Chappy425
author_rank: Newbie
timestamp: November 27, 2022, 01:25:06 am
content: Resurrecting an old thread. Brilliant idea. I just completed the same repair on an RG501. I accidentally inserted it into my TM500 bay without realising that it had a broken pull tab. I was able to free it from the bay by removing the TM500 bay cover and then prying up the latch release bar mechanism from the side of the now exposed Plug-In. Easier than taking the front panel off of the Plug-In to access the screw that secures the release bar mechanism to the Plug-In frame. As well, after fabricating the part, I was able to insert it into the slot on the mechanism without having to take anything apart. Took me less than 30 min.Thanks for sharing your great idea CatalinaWOW.Sincerely,Steve