Open and make visual check for internal dirt, corrosion, loose connections and excessive humidity (check desiccant), needed. Clean, repair and change desiccant as Battery check: Turn function switch to "A" ratemode, turn speaker on, reduce threshold to zero for maximum speaker noise and turn light on, then check for "error" legend ON and "Batt. OK" legend OFF; replace batteries if this condition exists. Check reset function. Check time base on one scaler mode preset time. Put function switch in high voltage (HV) position. varied, the HV reading should vary from 400 to 1400. 7. B. Il. As the HV potentiometer is Turn funetion switch to OFF and close PRS-1. Probe Operational Check 1. Make visual check of probe, probe cable and cable connector for dirt, corrosion, or damage, Clean and repair as needed, 2. Connect probe to PRS-1 and perform appropriate operational check procedure in the condensed instrument proceduresat the rear of this report. a. Calibration factor pots located on rate multiples board. b, "Hot," "Medium" and "Cool" check sources: 1) "Hot" 90sr-y: 10,000-20,000 cpm (2m). 2) "Hot" 2414m: 300,000-400,000 dpm. 3) "Med," 2414m: 20,000-40,000 dpm. 4) "Cool" 2414m: 3,000-5,000 dpm. 3. Cheek for noisy probe cable. Repair as needed. 4. Check for light leaks in AC-3, RASP-1 and SPA-1 probes, If necessary repair or replace mylar face and recalibrate probe. 5. Any probe that fails, during the operational check, to give the current reading (+ 20%), or whose efficiency is not within 20% of the efficiency listed on the calibration sticker, must be recalibrated or repaired. CALIBRATION PROCEDURE Instrument should be calibrated at three-month intervals using the procedures which follow: Each probe should have a calibration sticker affixed showing: (1) the name of the technician who calibrated the probe, (2) date of last calibration, (3) the calibration due date (three months after the last calibration), and (4) other data as specified in the calibration procedure for each probe type. In these procedures "Hot" and "Medium" sources mean the following: "Hot" 90sr-y: 10,000-20,000 epm (2m) "Hot" 241m or 239py; 300,000-400,000 dpm "Med." 241m or 239pu; 20,000-40,000 dpm A-29-2