Help: Hickok Western Electric KS-15750 Calibration

HP8903B

Member
2010-06-06 8:17 pm
I am trying to calibrate a Hickok KS-15750.

I attached the calibration procedures.

Could someone clarifies section 5. Micromhos step "d" and "e" ?

After step "c", I went to step "g" and the readings are correct except "Low 6000" and "Low 600"

Also, the location of R15 - R18, R28, R29, and R42. Particularly R15 and R42 ?
 

Attachments

  • Hickok KS-15750-L1 Manual.pdf
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The "shunt pot" referenced in 5d is the one controlled by the Shunt dial. It is a special dual resistor (R4-R5) pot made by Mallory, identified by Item No. 26 on your parts list. When Hickok initially installed this part, the individual pot cases (front and rear) were free to turn independently. Following the attached calibration procedure, the Hickok production team would: ensure the function switch was set to "3000 High", set the Shunt dial on 73, press the locking P4 button to set the tester to the Dynamic Transconductance test function, and then would rotate the rear section of the pot until the main meter read 1000. This properly calibrates the two circuits on either side of the 150 ohm sections of the pot. Checking to be sure the Shunt dial is still set on 73, and the main meter is still reading 1000, they would lock the rear section of the shunt pot to the front section by placing a dab of solder on the seam between the two pot halves (5e). If you find that as you follow this procedure, set the Shunt dial to 73, punch in P4, and your main meter reads 1000 (plus or minus two divisions, or in other words, between 900 and 1100) you should be good to go. If not, you are going to have to get out the soldering iron and the solder sucker to free the rear half of the pot and re-calibrate it. Does that clear things up?