《Alto_L-12,_16,_20_(Ver.2)_Mixer_Service_Manual电路图.pdf》由会员分享,可在线阅读,更多相关《Alto_L-12,_16,_20_(Ver.2)_Mixer_Service_Manual电路图.pdf(91页珍藏版)》请在收音机爱好者资料库上搜索。
1、Service MODEL: L-12/16/20 Version 2.0 RadioFans.CN 收音机爱 好者资料库 CONTENTS 1. Introduction.2 2. Specification.3 3. Black Diagram5 4. Schematic Diagram.6 5. PCB Layout25 6. Wiring Diagram.41 7. Test Procedure.42 8. Exploded Views b. Input the signal at 2.5kHz, Turn EQ MID knob of the relating channel clo
2、ckwise to the max (+12), the output is +12dBu( 2dB), then turn EQ MID knob of the relating channel counter-clockwise to the min. (-12), the output is 12dBu( 2dB); c. Input the signal at 15kHz, Turn EQ HIGN knob of the relating channel clockwise to the max (+15), the output is +15dBu( 3dB), then turn
3、 EQ HIGH knob of the relating channel counter-clockwise to the min. (-15), the output is 15dBu( 3dB); 4. test DSP a. Input the signal from MIC1, output the signal from MAIN MIX OUTPUT, turn AUX RTN2(DFX)clockwise to the MAX, turn PRESETS and VARATIONS knobs, the signal will be processed by DSP, if t
4、he level of the signal is over-high, PEAK LED will be illuminated to red, press DFX MUTE button, Bypass the signal, press the footswitch, which is connected to DFX FOOSWITCH, the signal will get out of BYPASS. b. Input the signal from MIC 1 to MIC 4, output the signal from AUX SEND S1, turn AUX 2 /D
5、FX TO AUX 1 counter-clockwise to the MAX., turn PRESET and VARATIONS knobs, the signal will be processed by DSP. (do not need to test L6 with this step) 5. Sampling test Connecting L 6 to a power amplifier and speakers, listening to the sound, no noise is OK. Company preset: turn all volume knobs to
6、 the MIN. other control knobs to the middle, all switches to the position of OFF. DONE 45 8. Exploded Views 30F-CVR1 136HK03983PC boardP-L12PU1-SMD 137HB00955PCBL12PU1_VER050316 138CI00075SMD ceramic capacitor 06030.1uF/50V Y5V +80,-20%C5,C6 139RD00007SMD fixed resistor 1/8W120 5% 0805 R1,R2,R3,R4,R
7、5,R6,R7,R8,R9,R10,R11,R12 ,R13,R14,R15,R16,R17,R18,R19,R20,R21, R22,R23,R24,R25,R26,R27,R28,R29,R30, R31,R32,R33,R34,R35,R36,R37,R38,R39, R40,R41,R42,R43,R44,R45,R46,R47,R48, R56,R57 140CI00051SMD ceramic capacitor 060322PF/50V C0G5%(C1608C0G1H220JT)/TDKC4 141RD00107SMD fixed resistor 1/10W30K 5% 06
8、03R55 142RD00353SMD fixed resistor 1/10W36K 5% 0603R50 143RD00352SMD fixed resistor 1/10W3.6K 5% 0603R49 144SG00122SMD integrated circuitNJM4580M-TE3U1 145RD00440SMD fixed resistor 1/8W5.1K 5% 0805R51,R52,R53,R54 146AE00221tin soldering pasteSJ-617 147AC00002solder wire63/37% 148HK03984PC boardP-L12
9、PU2-DIP 149CB00003electrolytic capacitor0.22uF/50V 5*11mm C16,C16-1,C16-2,C17,C17-1,C17-2,C17-3, C16-3,C18,C18-1,C18-2,C18-3,C50,C50-1, C51,C51-1,C52,C52-1 150CB00074electrolytic capacitor1000uF/10V 8*11mmC19,C19-1,C19-2,C19-3,C53,C53-1 151HC00321connector(male)14P 2.0mm 180CN1,CN2,CN4 152HC00524con
10、nector(male)15P 2.0mm 180CN3 153CB00029electrolytic capacitor22uF/35V 5*11mm C9,C9-1,C9-2,C9-3,C10-1,C10,C10-2,C10-3 154CB00175electrolytic capacitor47uF/25V SLL 5*11mm C107,C108,C109,C110,C7,C7-1,C7-2,C7-3, C8,C8-1,C8-2,C8-3,C54,C54-1,C55,C55-1, C56,C56-1,C57,C57-1 155CB00042electrolytic capacitor4
11、7uF/63V 105 LZ 8*11mm C12,C12-1,C12-2,C12-3,C13,C13-1,C13-2, C13-3,C36,C36-1,C37,C37-1 156RA00505precise resistor 1/4W6.81K M type R1,R1-1,R1-2,R1-3,R2,R2-1,R2-2,R2-3, R38,R38-1,R39,R39-1 157SB00175transistor2SA970-BL(TE2;T) TR1,TR1-1,TR1-2,TR1-3,TR2,TR2-1,TR2-2, TR2-3,TR6,TR6-1,TR7,TR7-1 158HC00126
12、balance MIC jackJY-5042-030G female plug 180X3,X3-1,X3-2,X3-3,X6,X6-1 159HC00125MIC jackJY-6351G-02-250 X1,X1-1,X1-2,X1-3,X2,X2-1,X2-2,X2-3,X4, X4-1,X5,X5-1,X7,X8,X9,X10,X11,X12 160SD00007integrated circuitBA15218N (M5218L substitute)U8,U9,U10,U11 161HC00403RCA jackSCP6873NS3232T2 4PX13 162HK03985PC
13、 boardP-L12PU2-SMD 163HB00956PCBL12PU2_VER030530 164CI00059SMD ceramic capacitor 0603100PF/50V NPO 5% C58,C58-1,C59,C59-1,C60,C60-1,C61, C61-1,C91,C92,C93,C94,C95,C96,C97,98 165CI00075SMD ceramic capacitor 06030.1uF/50V Y5V +80,-20% C24,C25,C26,C27,C28,C29,C30,C31,C32, C33,C34,C35,C63,C64,C65,C66,C6
14、7,C68, C69,C70,C71,C72,C73,C74,C75,C76,C77, C78,C79,C80,C81,C82,C83,C84,C85,C86, C87,C89,C90,C88 53 No. Part No. DescriptionSpecificationRemark 166RD00101SMD fixed resistor 1/10W10K 5% 0603 R70,R70-1,R71,R71-1,R76,R76,R77,R78, R79,R80,R81,R82,R83,R84,R85,R86,R87, R92,R93,R94,R95 167RD00214SMD precis
15、e resistor 1/10W10.0K 1% 0603 R26,R26-1,R26-2,R26-3,R27,R27-1,R27-2, R27-3,R61,R61-1,R62,R62-1 168CI00071SMD ceramic capacitor 06030.01uF/50V X7R 10% C1,C1-1,C1-2,C1-3,C2,C2-1,C2-2,C2-3, C38,C38-1,C39,C39-1 169RD00069SMD fixed resistor 1/10W120 5% 0603R104,R104-1,R104-2,R104-3 170RD00007SMD fixed re
16、sistor 1/8W120 5% 0805 R96,R97,R98,R99,R100,R101,R102,R103 171RD00104SMD fixed resistor 1/10W18K 5% 0603 R66,R66-1,R67,R67-1,R68,R68-1,R69, R69-1 172RD00083SMD fixed resistor 1/10W1.0K 5% 0603R31,R32 173RD00351SMD fixed resistor 1/10W1.3K 5% 0603R28,R28-1,R28-2,R28-3,R64,R64-1 174RD00201SMD precise
17、resistor 1/10W1.50K 1% 0603 R15,R15-1,R15-2,R15-3,R16,R16-1,R16-2, R16-3,R40,R40-1,R41,R41-1 175CI00065SMD ceramic capacitor 06030.001uF/50V X7R 10% C14,C14-1,C14-2,C14-3,C15,C15-1,C15-2, C15-3,C40,C40-1,C41,C41-1 176RD00306SMD fixed resistor 1/10W20K 5% 0603 R17,R17-1,R17-2,R17-3,R18,R18-1,R18-2, R
18、18-3,R19,R19-1,R19-2,R19-3,R42,R42-1, R43,R43-1,R44,R44-1,R45-1,R45,R46, R46-1,R47,R47-1,R73,R73-1,R75,R75-1, R88,R89,R90,R91 177CI00051SMD ceramic capacitor 060322PF/50V C0G5%(C1608C0G1H220JT)/TDK C3,C3-1,C3-2,C3-3,C4,C4-1,C4-2,C4-3, C5,C5-1,C5-2,C5-3,C6,C6-1,C6-2,C6-3, C42,C42-1,C43,C43-1,C44,C44-
19、1,C45, C45-1,C46,C46-1,C47,C47-1,C48,C48-1, C49,C49-1, C99, C100, C101, C102, C103, C104,C105,C106,C111,C112,C113,C114 178RD00204SMD precise resistor 1/10W2.49K 1% 0603 R3,R3-1,R3-2,R3-3,R4,R4-1,R4-2,R4-3, R5,R5-1,R5-2,R5-3,R6,R6-1,R6-2,R6-3, R7,R7-1,R7-2,R7-3,R8,R8-1,R8-2,R8-3, R9,R9-1,R9-2,R9-3,R4
20、8,R48-1,R49,R49-1, R50,R50-1,R51,R51-1,R52,R52-1, R53, R53-1,R54,R54-1 179CI00062SMD ceramic capacitor 0603330PF/50V NPO 5C11,C11-1,C11-2,C11-3,C62,C62-1 180RD00105SMD fixed resistor 1/10W22K 5% 0603R72,R72-1,R74,R74-1 181SG00122SMD integrated circuitNJM4580M-TE3 U1,U1-1,U1-2,U1-3,U2,U2-1,U2-2,U2-3,
21、 U3,U3-1,U4,U4-1,U5,U5-1,U6,U7 182RD00078SMD fixed resistor 1/10W470 5% 0603 R20,R20-1,R20-2,R20-3,R21,R21-1,R21-2, R21-3,R55,R55-1,R56,R56-1 183RD00355SMD fixed resistor 1/10W4.7 5% 0603 R10,R10-1,R10-2,R10-3,R11,R11-1,R11-2, R11-3,R12,R12-1,R12-2,R12-3,R35,R35-1, R36,R36-1,R37,37-1 184RD00210SMD p
22、recise resistor 1/10W5.11K 1% 0603 R22,R22-1,R22-2,R22-3,R23,R23-1,R23-2, R23-3,R24,R24-1,R24-2,R24-3,R25,R25-1, R25-2,R25-3,R57,R57-1,R58,R58-1,R59, R59-1,R60,R60-1 185RD00365SMD precise resistor 1/10W5.62K 1% 0603 R13,R13-1,R13-2,R13-3,R14,R14-1,R14-2, R14-3 186RD00113SMD fixed resistor 1/10W62K 5
23、% 0603R30,R30-1,R30-2,R30-3,R63,R63-1 187RD00097SMD fixed resistor 1/10W6.8K 5% 0603R29,R29-1,R29-2,R29-3,R65,R65-1 188SE00028SMD rectifier diodeBAS316,115D1,D1-1,D1-2,D1-3,D2,D2-1 189SF00053transistorMMBT3906(SOT-23)/(PHI) TR8,TR8-1,TR9,TR9-1,TR10-1,TR3,TR3-1, TR3-2,TR3-3,TR4,TR4-1,TR4-2,TR4-3, TR5
24、,TR5-1,TR5-2,TR5-3,TR10 190AE00221tin soldering pasteSJ-617 191AC00002solder wire63/37% 192HK03991PC boardP-L12MN2-DIP 193RA00174fixed resistor 1/4W47 M typeR52,R53 194CB00009electrolytic capacitor1uF/50V 4*7mm C21,C21-1,C21-2,C21-3,C22,C22-1,C22-2, C22-3 195CB00175electrolytic capacitor47uF/25V SLL
25、 5*11mm C2,C2-1,C2-2,C2-3,C3,C3-1,C3-2,C3-3, C4,C4-1,C4-2,C4-3,C28,C28-1,C28-2,C28-3, C24,C25,C26,C27 54 No. Part No. DescriptionSpecificationRemark 196CF00023metal-film capacitor MSC0.033uF/63V 5% CASE01 C11,C11-1,C11-2,C11-3,C12,C12-1,C12-2, C12-3 197CF00003metal-film capacitor MSC0.0015uF/100V 5%
26、 CASE01C10,C10-1,C10-2,C10-3 198CF00012metal-film capacitor MSC0.0068uF/100V 5% CASE01 C7,C7-1,C7-2,C7-3,C8,C8-1,C8-2,C8-3, C1,C1-1,C1-2,C1-3 199HI00236push-button switch-RS2-stage 6P PS-9226A(SELF-LOCK) SW3,SW3-1,SW3-2,SW3-3,SW5,SW5-1, SW5-2,SW5-3,SW6,SW6-1,SW6-2,SW6-3, SW7,SW7-1,SW7-2,SW7-3,SW2,SW
27、2-1, SW2-2,SW2-3,SW1,SW1-1,SW1-2,SW1-3 200HI00237push-button switch-RS2stage 12P PS-13422R(SELF-LOCK)SW4,SW4-1,SW4-2,SW4-3 201RC00284slide potentiometerD10K RF6011YP600F-10KD(SAS1)VR5,VR5-1,VR5-2,VR5-3 202RC00356potentiometerZ10K RD09F1130042-10KZ(SAS1);30FVR11,VR11-1,VR11-2,VR11-3 203RC00358potenti
28、ometer B50K-RD09F113A223-50K2BT(SAS1);30F-C VR1,VR1-1,VR1-2,VR1-3,VR2,VR2-1, VR2-2,VR2-3,VR4,VR4-1,VR4-2,VR4-3 204RC00359potentiometer W50K RD09F113A224-50K4BT(SAS1);30F-C VR6,VR6-1,VR6-2,VR6-3,VR7,VR7-1,VR7-2, VR7-3,VR8,VR8-1,VR8-2,VR8-3,VR9,VR9-1, VR9-2,VR9-3,VR10,VR10-1,VR10-2,VR10-3 205RC00366po
29、tentiometer C500KRD12L123A43D-500K15C*2(SAS1)30F-C VR3,VR3-1,VR3-2,VR3-3 206SA00054L.E.D3m/m round(yellow)long foot 26LD1,LD1-1,LD1-2,LD1-3 207SA00053L.E.D3 round(red)long foot 26mmLD2,LD2-1,LD2-2,LD2-3 208SA00051L.E.D3 orange, green BOG303bLD3,LD3-1,LD3-2,LD3-3 209NI01782LED spacer supportLEDS-11 1
30、1mm LD1,LD1-1,LD1-2,LD1-3,LD2,LD2-1,LD2-2, LD2-3 210NI02588LED spacer supportLED3*11 11mmLD3,LD3-1,LD3-2,LD3-3 211HA02446wire14P(male)-14P(female) 60mm UL1007 28AWGCN1,CN2 212HA01564row-wire connector wiring5P(male)-5P(female) 180CN3 213HC00154connector2.54 180 2*10P(gold-plated) 6/11.6mmCN4 214HK03
31、999PC boardP-L12MN2-SMD 215HB00959PCBL12MN2_VER030530 216RD00083SMD fixed resistor 1/10W1.0K 5% 0603R51,R51-1,R51-2,R51-3 217RD00088SMD fixed resistor 1/10W2.2K 5% 0603R23,R23-1,R23-2,R23-3 218RD00090SMD fixed resistor 1/10W3.0K 5% 0603R1,R1-1,R1-2,R1-3 219RD00091SMD fixed resistor 1/10W3.3K 5% 0603
32、R26,R26-1,R26-2,R26-3 220RD00092SMD fixed resistor 1/10W3.9K 5% 0603R18,R18-1,R18-2,R18-3 221RD00093SMD fixed resistor 1/10W4.7K 5% 0603 R29,R29-1,R29-2,R29-3,R30,R30-1,R30-2, R30-3,R49,R49-1,R49-2,R49-3 222RD00094SMD fixed resistor 1/10W5.1K 5% 0603 R6,R6-1,R6-2,R6-3,R7,R7-1,R7-2,R7-3, R8,R8-1,R8-2
33、,R8-3,R9,R9-1,R9-2,R9-3,R10, R10-1,R10-2,R10-3,R11,R11-1,R11-2,R11-3 R12,R12-1,R12-2,R12-3,R13,R13-1,R13-2, R13-3 223RD00095SMD fixed resistor 1/10W5.6K 5% 0603 R24,R24-1,R24-2,R25,R25-1,R25-2,R25-3, R24-3 224RD00096SMD fixed resistor 1/10W6.2K 5% 0603 R21,R21-1,R21-2,R21-3,R22,R22-1,R22-2, R22-3 22
34、5RD00097SMD fixed resistor 1/10W6.8K 5% 0603 R14,R14-1,R14-3,R15,R15-3,R16,R16-3, R15-1,R16-1,R17,R17-1,R17-3,R27,R27-1, R27-3,R28,R28-1,R28-3,R14-2,R15-2,R16-2, R17-2,R27-2,R28-2 226RD00099SMD fixed resistor 1/10W8.2K 5% 0603R43,R43-1,R43-2,R43-3 227RD00101SMD fixed resistor 1/10W10K 5% 0603 R2,R2-
35、1,R2-2,R2-3,R3,R3-1,R3-2,R3-3,R4, R4-1,R4-2,R4-3,R5,R5-1,R5-2,R5-3,R45, R45-1,R45-2,R45-3,R47,R47-1,R47-2,R47-3, R48,R48-1,R48-2,R48-3,R46,R46-1,R46-2, R46-3 228RD00102SMD fixed resistor 1/10W12K 5% 0603R20,R20-1,R20-2,R20-3 229RD00103SMD fixed resistor 1/10W15K 5% 0603R40,R40-1,R40-2,R40-3 230RD001
36、06SMD fixed resistor 1/10W27K 5% 0603R50,R50-1,R50-2,R50-3 55 No. Part No. DescriptionSpecificationRemark 231RD00116SMD fixed resistor 1/10W100K 5% 0603 R42,R42-1,R42-2,R42-3,R41,R41-1,R41-2, R41-3 232RD00125SMD fixed resistor 1/10W1.0M 5% 0603R19,R19-1,R19-2,R19-3 233CI00051SMD ceramic capacitor 06
37、03 22PF/50V C0G5%(C1608C0G1H220JT)/TDK C5,C5-1,C5-2,C5-3,C6,C6-1,C6-2,C6-3,C9, C9-1,C9-3,C9-2 234CI00063SMD ceramic capacitor 0603470PF/50V NPO 5C23,C23-1,C23-2,C23-3 235CI00075SMD ceramic capacitor 06030.1uF/50V Y5V +80,-20% C14,C14-1,C14-2,C14-3,C15,C15-2,C16, C16-2,C17,C17-1,C17-2,C17-3,C18,C18-1
38、, C18-2,C18-3,C19,C19-1,C19-2,C19-3,C20, C20-1,C20-2,C20-3 236SG00306SMD integrated circuitLM393DR(TI)/(MEXICO)U4,U4-1,U4-2,U4-3 237SE00011SMD rectifier diodeRLS4148 0.5A (LL-34) D2,D2-1,D2-2,D2-3,D3,D3-1,D3-2,D3-3,D4, D4-1,D4-2,D4-3 238SG00122SMD integrated circuitNJM4580M-TE3 U1,U1-1,U1-2,U1-3,U2,
39、U2-1,U2-2,U2-3,U3, U3-2 239SF00038transistorRK7002(ROHM)TR2,TR2-1,TR2-2,TR2-3 240SE00028SMD rectifier diodeBAS316,115D1,D1-1,D1-2,D1-3 241SF00053transistorMMBT3906(SOT-23)/(PHI)TR1,TR1-1,TR1-2,TR1-3 242AE00221tin soldering pasteSJ-617 243RD00074SMD fixed resistor 1/10W270 5% 0603R44,R44-1,R44-2,R44-
40、3 244AC00002solder wire63/37% 245HK04012PC boardP-L12MN1-DIP 246CF00003metal-film capacitor MSC0.0015uF/100V 5% CASE01C440,C441,C442 247RC00285slide potentiometer-dual unitD10K RF60112P600G-10KD*2(SAS1)VR5,VR16,VR38,VR39,VR56 248RC00284slide potentiometerD10K RF6011YP600F-10KD(SAS1)VR53,VR54,VR55,VR
41、66 249CB00024electrolytic capacitor10uF/16V 4*7mmC443,C444 250RA00185fixed resistor 1/4W120 M typeR597,R598 251CF00054metal-film capacitor MSC0.012uF/63V 5% CASE01 C13,C14,C15,C16,C17,C18,C19,C20,C76, C77,C85,C86,C107,C108,C115,C116 252CF00001metal-film capacitor MSC0.001uF/63V 5% CASE01 C21,C22,C23
42、,C24,C75,C84,106,C114 253CF00038metal-film capacitor MSC0.22uF/63V 5% CASE02 C295,C296,C303,C304,C305,C306,C313, C314,C321,C322,C323,C324 254CB00009electrolytic capacitor1uF/50V 4*7mm C423,C424,C454,C455,C458,C460,C461, C463,C464,C457 255CB00011electrolytic capacitor2.2uF/50V 5*11mmC380 256CF00022me
43、tal-film capacitor MSC0.022uF/100V 5% CASE01 C291,C292,C293,C294,C301,C302,C309, C310,C311,C312,C319,C320 257CF00005metal-film capacitor MSC0.0022uF/63V 5% CASE01 C289,C290,C297,C298,C299,C300,C307, C308,C315,C316,C317,C318 258CF00006metal-film capacitor MSC0.0033uF/100V 5% CASE01 C33,C34,C35,C36,C3
44、7,C38,C39,C40,C79, C80,C88,C89,C110,C111,C118,C119 259CB00018electrolytic capacitor4.7uF/25V 4*7mmC436,C438,C439 260RA00174fixed resistor 1/4W47 M typeR745,R746 261CF00025metal-film capacitor MSC0.047uF/63V 5% CASE01 C41,C42,C43,C44,C81,C90,C112,C120 262CB00175electrolytic capacitor47uF/25V SLL 5*11
45、mm C1,C2,C3,C4,C5,C6,C7,C8,C9,C10,C11,C12 ,C67,C68,C69,C70,C73,C74,C83,C92,C96, C97,C98,C99,C100,C101,C104,C105,C122, C123,C127,C128,C153,C154,C155,C156, C161,C162,C164,C163,C176,C179,C180, C184,C187,C188,C191,C192,C195,C196, C199,C200,C203,C204,C207,C211,C212, C215,C216,C219,C220,C239,C240,C243, C2
46、44,C247,C248,C252,C255,C256,C259, C260,C265,C266,C267,C268,C285,C286, C376,C377,C378,C383,C393,C384,C395, C396,C401,C417,C418,C419,C466,C467, C470,C471,C474,C475,C491,C492,C493, C494,C495,C496,C497,C498,C500,C501, C502,C503,C504,C505,C506,C507,C479, C175,C287,C288,C480,C486,C487,C397, C398,C183,C208
47、,C251,C394,C420,C402, C488,C489,C490,C499,C508,C510,C509 56 No. Part No. DescriptionSpecificationRemark 263RC00315slide potentiometerW100K RA3022-202-15DA-W100K-C VR57,VR58,VR59,VR60,VR61,VR62,VR63, VR64,VR65 264HI00236push-button switch-RS2-stage 6P PS-9226A(SELF-LOCK) SW2,SW5,SW6,SW7,SW9,SW12,SW13
48、, SW14,SW15,SW16,SW21,SW22,SW24, SW25,SW26,SW32,SW33,SW34,SW35, SW36,SW37,SW38,SW39,SW43,SW44, SW45,SW46,SW48,SW49,SW50,SW51, SW1,SW8,SW23,SW40,SW41 265HI00238push-button switch-RS2 stage 6P PS-9226A(NON-LOCK)SW47 266HI00237push-button switch-RS2stage 12P PS-13422R(SELF-LOCK) SW4,SW11,SW19,SW20,SW27
49、,SW28,SW29 ,SW30,SW31,SW42,SW3,SW10,SW17, SW18 267HI00161relayRY-5W-K,5VRL1 268HI00195rotary switchSDB161PVB15.5F-1-4-16-16PCEN1,EN2 269RC00360potentiometer B50K RD12L12CA23A- 50K3BT*2(SAS1);30F-C VR1,VR2,VR3,VR4,VR12,VR13,VR14,VR15, VR24,VR25,VR26,VR27,VR41,VR42,VR43, VR40 270RC00359potentiometer W50K RD09F113A224- 50K4BT(SAS1);30F-C VR6,VR7,VR8,VR9,VR10,VR17,VR18,VR19, VR20,VR21,VR28,VR29,VR31,VR32,VR33, VR34,VR35,VR36,VR37,VR48,VR49,VR50, VR51,VR71,VR72,VR30,VR69,VR70 271RC00361potentiometer W50K RD12L12