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test_equipment:repair_coils_on_hp_attenuators [2013/01/08 19:00] |
test_equipment:repair_coils_on_hp_attenuators [2013/01/08 19:00] (current) |
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+ | ====== Repair Coils on HP Attenuators ====== | ||
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+ | Just wanted to let you know I was able to repair and rewind the 4 damages bobbins. | ||
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+ | 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). | ||
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+ | 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. | ||
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+ | After finishing the bobbin repair and rewind, the attenuator actuators work great and I now have a working generator. | ||
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+ | 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? | ||
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+ | Thank you again for all the information and your help with the project. | ||
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+ | Steve | ||