Pioneer hfe pioneer solid state main amplifier troubleshoot free download

File name hfe_pioneer_solid_state_main_amplifier_troubleshoot.pdf

TICI.II{ICAL OIJIDI FOR $IRI|ICI TROUBLE SHOOTING METHODS IN SOLID STATE MAIN AMPLIFIER g- i I j* PIONEER' \/ SERVICE DEPARTMENT INTERNATIONAL DIVISION ! 3. WE ARE GOING TO STUDY HOW TO CHECK THE COMPLEMENTARY MAIN AMPLIFIER CIRCUITS WITH THE AID OF THIS SLIDE. 4. THIS IS THE MOST BASIC AND COMMONLY USED COMPLEMENTARY CIRCUIT. 5. ON THIS BASIC DIAGRAM, TRANSISTOR 1 IS FOR THE PRIMARY. STAGE AMPLIFICATION. TRANSISTOR 2IS FOR THE PRE-DRIVING PURPOSE, TRANSISTORS 3 AND 4 ARE FOR THE DRIVE-STAGE, AND TRANSISTORS 5 AND 6 ARE FOR THE POWER STAGE. 6. HERE, WE WILL OMIT FROM OUR STUDIES THE PRIMARY.STAGE AMPLIFIER SECTION OF TRANSISTOR 1, SINCE IT IS A VERY COMMON CI RCU IT OF CAPACI TOR-COUPL ED, EM ITTER.GROUND ED TYP E. 7. TRANSISTORS 3 AND 5 AS WELL AS TRANSISTORS 4 AND 6 ARE OF DARLINGTON.CONNECTION, SO THAT THEY MAY BE CONSIDERED AS N.P-N AND P-N-P TRANSISTORS, RESPECTIVELY. 8. SINCE THERE IS NO DIFFERENCE, AT LEAST THE DC FUNCTION IS CONCERNED, WHETHER TRANSISTORS 5 AND 6 ARE CONNECTED OR NOT,LET'S PROCEED WITH OUR SLIDE STUDIES WITH TRANSIS- TORS 5 AND 6 DISCONNECTED. 9. NOW LET'S CONSIDER THE DIRECT CURRENT FUNCTION OF THIS clRcUlT. lF Vcc lS APPLIED, A BlAs VOLTAGE tS GTVEN To TRANSIS- ToR 3 BY MEANS oF THE RESlsroRS R6 AND Rlo. THEN THE col- LECTOR CURRENT OF TRANSTSTOR 3, OR tg3, FLOWS, AND A VOLT_ AGE ARISES AT THE CENTER POINT. 10_ A BIAS VOLTAGE IS GIVEN TO TRANSISTOR 2 FROM THE CENTER POINT THROUGH vRr wHtcH ts FoR REGULATTNG THE CENTER VOLTAGE. THEN THE COLLECTOR CURRENT FOR TRANSISTOR 2. oR tcz, STARTS TO FLOW, AND THE COLLECTOR VOLTAGE, OR vc2, DROPS. 11. THE COLLECTOR OF TRANSISTOR 2 IS DIRECTLY CONNECTED TO THE BASE OF TRANSISTOR 4 SO THAT THE BASE VOLTAGE, OR vB4, oF TRANSTSTOR 4 ALSO DROPS, 12. SINCE TRANSISTOR 4 IS A P.N-P TYPE, A BIAS VOLTAGE IS IN FACT GIVEN TO TRANSISTOR 4, AND CURRENT THUS FLOWS TO TRANSIS- TOR 4. 13. THE lNsrANT vcc ls APPL|ED, THE VOLTAGE AT THE GENTER porNT BEcoMES ALMosr AS HlcH As vcc trsELF,BECAUSE A BIAS voLTAGE IS GIVEN TO TRANSISTOR 3. 14. BUT AS TRANSISTOR 2 BEGINS TO FUNCTION, AND FURTHER, TRANSISTOR 4 FUNCTIONS, THE VOLTAGE OF THE CENTER POINT GRADUALLY DROPS FROM THE VALUE CLOSE TO Vcc. 15. NOW, LET'S CONSIDER THE CASE WHERE THE CENTER VOLTAGE HAS DECREASED AND t{AS BECOME LOWER THAN ll2vcc. THE BIAS VOLTAGE FOR TRANSISTOR 2 BECOMES INSUFFICIENT, BECAUSE OF THE DIRECT.CURRENT FEEDBACK FROM THE CENTER POINT THROUGH vRl TO TRANSISTOR 2. THE COLLECTOR CURRENT, lc2, DECREASES AND THE COLLECTOR VOLTAGE Vcz GETS HIGHER. 16. FOR TH