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TROUBLESHOOTING & REPAIR | ||
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MOUNTING OF STUD TYPE DIODES TO ALUMINUM HEAT SINKS (CONT’D)
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PROCEDURE
1.Loosen the appropriate diode nut and remove the diode that is to be replaced.
2.Clean the area on the heat sink around the diode mounting surface using a putty knife, or similar tool, DO NOT SCRATCH THE DIODE MOUNTING SURFACE.
3.Polish each heat sink's mounting surface using NO. 000 fine steel wool. Wipe surface clean with
alint free cloth or paper towel.
4.Inspect the mounting surfaces of each new diode. Remove all burrs and wipe clean. Do not use steel wool or any abrasive cleanser on the diode mounting surface.
5.Apply a thin (0.0003" to 0.0007") uniform layer of E1868 (Dow Corning 340) heat sink compound to the heat sink mounting surface.
a.Do not apply compound to diode stud or mounting threads.
b.The diode threads must be clean and free of defects so that the nut can be finger tightened before applying torque. A "slip" type torque wrench must be used to tighten the diode nut.
6.Tighten the diode nuts to the specifications in the following table.
a.The nuts for diodes with steel studs are to be started by hand and then torqued as per the following table.
b.The nuts for diodes with copper studs are to run on all the way by hand then torqued as per the following table.
| DIODE STUD |
| FOOT- |
| INCH- |
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| SIZE |
| POUNDS |
| POUNDS |
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| 3/4 - 16 |
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| 3/8 - 24 |
| 10±.5 |
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| 1/4 - 28 |
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c.Turn a minimum of 1/2 turn more while torquing per the table.
