Harris Platinum HT EL 2000LS Technical Manual

Harris Platinum HT EL 2000LS Technical Manual Manual pdf 48 page image

Additional filters may be ordered from HARRIS to assist inmaintenance. Harris filter part number is 448-0974-000. Thisfilter is a standard filter size 14in. x30in. x1in. The filter mediais a coated fiberglass mat.The power supply filter Harris part number is 943-5285-126.5.3.2 MOV’SPeriodically visually inspect all MOV’s to ensure proper tran-sient protection. In addition to regular inspection, check afterthunder storms. Replace any suspect units exhibiting physicaldamage.5.3.3 SemiconductorsRoutine checking of semiconductors used in the Transmitter isnot required.The best check of semiconductor performance is actual operationin the transmitter. When semiconductors are replaced, checkcircuitry operation which may be affected. Replacement semi-conductors should be of the original type or a recommendeddirect replacement. Preventive maintenance of transistors is ac-complished by performing the following steps:a. Inspect the semiconductors and surrounding area as accu-mulations of dirt or dust could form leakage paths. Dirt onheat sink surfaces can reduce air flow and be a thermalbarrier.b. Examine all semiconductors for loose connections or cor-rosion. RF and other power transistors have specific fas-tener torque requirements that must be followed.5.3.3.1 CapacitorsPreventive maintenance of capacitors is accomplished as fol-lows:a. Examine all capacitor terminals for loose connections orcorrosion.b. Ensure that component mountings are tight.c. Examine the body of each capacitor for swelling, discol-oration, or other evidence of breakdown.d. Inspect electrolytic capacitors for leakage signs.e. Use standard practices to repair poor solder connectionswith proper soldering tools.5.3.3.2 Fixed ResistorsPreventive maintenance of fixed resistors is accomplished by thefollowing steps:a. When inspecting a chassis, printed-circuit board, or dis-crete component assembly, examine resistors for dirt orsigns of overheating. Discolored, cracked, or chipped com-ponents indicate a possible overload.b. When replacing a resistor ensure the replacement valuecorresponds to the component designated by the schematicdiagram.c. Clean dirty resistors with a small brush.5.3.3.3 TransformersPreventative maintenance of transformers is accomplished byperforming the following:a. Feel each transformer soon after power removal for signsof overheating.b. Inspect each transformer for dirt, loose mounting bracketsand rivets, loose terminal connections, and insecure con-necting lugs. Dust, dirt, or moisture between terminals maycause flashovers.c. Tighten loose mounting lugs, terminals, or rivets.d. Clean with a dry lint-free cloth. Use an approved cleaningsolvent if required.e. Clean corroded contacts or connections with crocus cloth.f. Replace defective transformers.5.3.3.4 RelaysReplace hermetically sealed relays if defective. Check otherrelays for:a. The relay is mounted securely.b. Connecting leads are not frayed and the insulation is notdamaged.c. Terminal connections are tight and clean.d. Moving parts travel freely.e. Spring tension is correct.f. Contacts are clean, adjusted properly and make good con-tact.g. The coil shows no signs of overheating.h. Clean any dirty or corroded terminal connection.5.4 Performance ChecksPerformance checks of multiburst response, linearity and ICPMwill indicate if adjustments are needed. Checks of control circuitoperation and metering calibration are recommended annually.5.5 AdjustmentsThe following are adjustment and alignment procedures. It isstrongly suggested that each procedure be read completely be-fore attempting any adjustments. The abbreviation CW is clock-wise and CCW is counter-clockwise.5.6 RF Power Measurements5.6.1 Through-Line MetersThrough-line wattmeters of known accuracy are acceptable forpower measurements. However, once factory calibrated as a set,the line section, sampling element and meter must be usedtogether. The metering will be more accurate if the measurementis in the upper third of the meter scale .Platinum™ Series5-2 888-2457-001WARNING: Disconnect primary power prior to servicing.