LeCroy 9354AM broken knob repair

[exit_failure]

A couple of days ago, I bought a LeCroy 9354AM in good working condition. The only things that was wrong with it, were some broken off knobs, including volts/div and time/div:




Dave Jones' has a video about how to disassemble the larger parts of a 9384C. It's exactly the same for a 9354AM except that mine doesn't have a floppy drive but a built in printer with a much shorter cable under the top cover.





After undoing two screws at both sides of the case, continue by unplugging the two ribbon cables connecting the CRT driver with the main processor board. Now you can pull the whole front panel including the CRT away from the main chassis (see Dave's video.)



Undo the four screws securing the control panel to the front cover.


         
Lift the keypad out of the font panel and guide the ribbon cable gently though its cut out. (Here, the replacement knobs are already in place since I forgot to take pictures of those steps before the repair.)



Pull the key pad's flat flex connector out of its socket.



Undo the screw holding the front cover and the PCB together.



One of the broken knobs. My first plan was to buy replacement part and just solder them in. The parts I would have needed were three Bourns ECW1D-Y32-BC0024 and one Bourns ECW0D-Y32-BC0024. These exact parts weren't really available in Germany but I found compatible ones with different axes on Mouser and Digikey. German electronics shops didn't have them unfortunately. The 20€ for the parts would have been ok but the 20€ postage pushed it over the limit on what I wanted to spend on the repair and since the rotary encoders that were already in the scope still worked, I looked for another solution:


         
I searched a couple of local euro-shops and found these 7mm knitting needles and some epoxy totalling 4€


Since 7mm where too thick (doh!) I had to sand them down a millimetre

         
I cut them to size and used my dremel to cut a tongue on one end and the respective groove into the axes of the encoders.



I glued the knitting needle pieces in place with the epoxy, let it set and cut them to length using a little circular saw blade for my dremel.



Reattaching the front cover



I had some knobs that fit quite well lying around from another project.



Works like a treat. 

The only thing left to do is replace the incredibly loud fan in the back of the 'scope. I already ordered a replacement fan and will put it in next weekend.


/edit
spelling

[precaud]

Nice work! I look forward to hearing about the replacement fan's noise compared to the original. I have a 9430 that I'd like to quiet down a little in that department...