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test_equipment:repair_coils_on_hp_attenuators [2013/01/08 19:00] (current)
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 +====== Repair Coils on HP Attenuators ======
 +Just wanted to let you know I was able to repair and rewind the 4 damages bobbins.  ​
 +I first tried using the original #35 AWG magnet wire size, but due to the physical repair I had to do on the damaged plastic bobbins I was not able to wind the same number of turns as the original coil, so the resistance was too low (about 42 Ohms instead of the original 50 Ohms).  ​
 +The sink transistors in the 75468'​s are rated at 500mA maximum, so 42 Ohms at 24 VDC makes the current too high.  It may have worked, but I did not want to risk it.  I changed the wire size to #36 AWG and ended up with about 60 Ohms.  ​
 +After finishing the bobbin repair and rewind, the attenuator actuators work great and I now have a working generator.  ​
 +The rubber grommets that physically attach the plastic attenuator arm to the actuator are starting to dry out and will be a problem sometime in the future. ​ Any suggestions on replacements?​
 +Thank you again for all the information and your help with the project.
test_equipment/repair_coils_on_hp_attenuators.txt ยท Last modified: 2013/01/08 19:00 (external edit)
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