HP 3438A Operating And Service Manual

Also see for 3438A: OPERATING & SERVICE MANUAL

Model 3438ASECTION VADJUSTMENT PROCEDURESSection V5-1. INTRODUCTION. 5-7. PRE-ADJUSTMENT PROCEDURES.5-2. This section of the manual contains Pre-Adjustmentand Adjustment Procedures.5-3. EQUIPMENT REQUIRED.5-4. The Test Equipment required for these AdjustmentProcedures is listed in Table 5-1. Equipment that satisfiesthe critical specifications given in the table may besubstituted for a recommended model.5-5. ADJUSTMENT INTERVAL.5-6. Adjustment Procedures should be performed atleast once every year to ensure proper calibration of theMultimeter.piicwA,,,,,IIT i ~ e ~ eAdjcrsrtnenr Proc~rrlctresare,/br use hyqual~/iedpersotznel on!r.. To avoid elec,rric,alsl~uc,k,do nor pei-/:form anl, .rervic,ing orherr/lan rhar contained in [he operaringinsrruc.rions or Perfortnunc,e Tesrs unlc,.ss vouore qualj/i'ecl ro do so.Wear (,lean c,otron g1ove.s n7hen \corking otzthe c,irc,uirhoards or .swirche.s. Cunrat~~inarionq/~/i'nger,~~rinr.son i ~ i g hin~pedat~c.epoit~r.s\t,illdegracle rhe /~c,r/:fort~iunc~e( J / ' rhr insrrunlc,tzr..V.vlon glo1,e.s should nor he ~t.ornd ~ t rl o [hepo.ssihi/irj: (I,/' sraric c,harge hcrildup.The hj,hrid c,ircuirs in rile .Vulrirnerc,r maj. hepertnanenr!r damaged h!. sraric disc,harge,frotn a hand or roo1 u5he11rhe .Vtrlritnertv- isdisassernhled. The, proc,edure.s be lo^. tnusr he,/bllo~z~edro prevc,nr /~o.s.sihle ~latnage.I . Ground rhe hand ~ ) h i l edi.sassetnhlinga t ~ d14,orXingon the .V~tliinlt,rer.Conducri~st,wri.srhand.s (-/I[)- Purr No. 00970-67900) areavailable ,/or rhis p~rrpose.2. Arrac,h rile Mulritnerrr C O M rerrnit~alro earth ground. Touc,/i all tools ro cwrrhground ro ren~ovesraric, c.i~argc,.sht:fore u.singrht7tn on rhe .Ilulritnerer.3. Use a soldering iron with a groutldc,d rip.5-8. Disassembly Instructions:a . Disconnect the Multimeter Power Cord.b. Remove two top cover fastening screws (backpanel) and remove top cover.c. Remove five A3 shield mounting screws (backpanel). This will allow the A3 P C and shield assembly(HP-1B) to slide forward % of a n inch.d . Disconnect W5 from the A3 P C assembly. W5 is agreen, yellow. orange, red, brown cable connecting A3 to4 2 (display).e. Remove the .A3 P C and shield assembly by slidingthe assembly forward and upward. With the Multimeterfront panel facing you, place the A3 PC and shieldassembly to the right side of the Multimeter.f. Re-connect W5 to the A3 P C assemblyg. All adjustments can be made without removing theinternal A l shield.5-9. Test Point and Adjustment Locations.5-10. Fold out and refer t o Figure 5-4. AdjustmentLocator for the remainder of this procedure. 'TheAdjustment Locator shows Test Points. 'Test Jumpers,Adjustment and Connector locations.NOTEThe .Mulritnc,rer .shoctld Lvartn up ,for 15tninures hefbre per/urtning ihe Aclju.srt~~enrProcedure.5-11. ADJUSTMENT PROCEDURE.5-12. Adjustments should be made in the followingsequence:@ A + 7 V Power Supply Adjustment (R417).@ B U725 Back Gate Bias Adjustment (R603).@ 10 kHz Clock Frequency Adjustment (R9).@ A C Zero Adjustment (R203).@ 20 11 Range Zero Adjustment (R11 I).