NAD-6300-tape-sm 维修电路原理图.pdf

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1、MANUAL RadioFans.CN 收音机爱 好者资料库ALIGNMENT METHOD IMPORTANT I The tape path (heads, tape guides, capstan, plnch roller) should be cleaned and degaussed before alignment. I This tape recorder is designed to work well with a variety of tapes, however, maxlmum performance will be obtained with recommended

2、 tapes or similar tape formulations. Recommended tapes For North America For Europe-DIN Type 1 Maxell UDS-1 Maxell UD-I, BASF TP18 no, R723DG Type lI Mawell XL-I1 Maxell XL-11, Teac MlT-5561 TY Pe Maxell MX Maxell MX. Maxell MX 422 I All adjustments done with Dolby NR OFF. MPX filter (on back panel)

3、 OFF and BlAS FINE ADJUST in center position. DOLBY NR level 200 nWblm = 245 mV RMS on testpoints TP001(L) and TP002(R)KP003(L) and TP004(R) (PLAYBACWRECORDING) on Maln PCB; approximately 505 mV at line outputs. 1. TAPE SPEED Connect one output to Wow and Flutter Meter or Frequency Counter, Play spe

4、ed test tape TEAC MlT-111 = 3 kHz or TEAC MlT-211 = 3.15 kHz and adjust SVR851, for correct readlng on Wow and Flutter Meter or Frequency Counter.(See Fig. A) Tolerance: k 1 % 2. AZIMUTH Connect VWMs andlor Oscilloscope to outputs. Set tape selector to normal and start playing Azimuth tape TEAC MlT-

5、113 or MTT-114. Rotate azlmuth screw for maximum output andlor maximum and in phase on Osdlloscope. Reseal adjustment screw with nail pollsh or similar (do not use glue).(See Fig. B) 3. PLAYBACK EQ M I S ADJUSTMENT IS NOT NEEDED UNLESS THE HEAD HAS BEEN REPLACED OR REPAIR HAS BEEN DONE IN HEADAMP CI

6、RCUIT. Play levellazimuth tape TEAC MTT-256 and adjust SVU001(L) and SVR002(R) for identical output at 31516300 Hz (MT-255) or 25016300 Hz (M7T-256). Tolerance: 20.5 dB 4. PLAYBACK HIGH FREQUENCY EQ THIS ADJUSTMENT SHOULD BE DONE ONLY WHEN HEAD HAS BEEN REPLACED. Play frequency response tape TEAC Ml

7、T-258 or MTT-256U and check playback level at 14 kHz. Before adjust, cut the center of jumper leads E001(L) and E002(A). Adjust by dlsconnectlng R001(L) and R002(R) If 14 kHz Is too low and connecting E001(L) and E002(R) If 14 kHz Is too high. Leave same component values In both channels. Tolerance:

8、 -+I dB 5. PLAYBACK LEVEL Connect VWM to testpoints. Play Dolby NR lev% tape TEAC MTT-150 and adjust SVROO3(L) and SVROO4(R) for 245 mV RMS at testpoint TP001(L) and TP002(R) on Main PCB. Tolerance: k2.5 mV RMS Output should be approximately 505. mV RMS. 6. METER LEVEL Play Dolby NU level tape MlT-1

9、50 and adjust SVRSOl(L) and SVR502(R) so that 0 dB LEDS Just turn on. .I h 7. BlAS TRAP Insert a blank type 1 tape and start recording. Turn record level all the way down and set tape selector to type l V position. Connect VNMs andlor oscilloscope probe to testpoint MP201-3(L) and adjust F301 for mi

10、nimum. Connect probe to MP201-1 and adjust F302 for minlmum. Tolerance: Less than 300 mV RMS. 8. RECORD LEVEL Set tape selector to .we N tape. Qonnect audio oscillator to I I llne Inputs, tuh r&ord levela to maxlmum (clockwise). Adjust audlo oscillator frequency to 400 Hz and outputq that VTVMs read

11、 30 - 40 mV. (Use a condnlent referen-point on the VNMs). r I 8 1 L 2 Reset tape counteio 0 anb release pause to start recording. Record for approximately 5 seconds, rewind to 0 gn tape wunter and play back while observing the VTVMs. h e h $ s h o u l d Indicate the same level as when the tape was r

12、ecorde8djust SVRDO!5(L) and SVROO6(R) If neceseary and repeat the record 1 play procedure until the readings are the same. I Tolerance: 20.5 dB from record level. Less than 0.5 dB dlfferencs between channels. 9. BlAS ADJUST TYPE I TAPE (NORMAL) Set audlo generator to 1.2 kHz wlthout changing output

13、level. Reset tape counter to 0 and start recordlng. Afler 5 seconds change audlo generator frequency to 12 kHz (do not stop the machlne or change levels) and wntlnue recording for another 5 seconds. Stop and rewind to 0 on tape counter. Play back whlle obaeing VNMs. There should be no level differen

14、ce between the 1.2 kHz and the 12 kHz tone when played back. If 12 kHz Is different in level for 1.2 kHz, adjust SVRSOl(L) and SVR302(R) and repeat the record I play procedure until both frequencies play back at same level. Tolerance: f 0.5 dB WARNING: Greater tolerance will grossly affect the Dolby

15、 NR tracking and especially the Dolby C tracklng. Reoord level (step 8) should be checked and if necessary adjusted. RadioFans.CN 收音机爱 好者资料库10. PEAKING CIRCUIT TYPE I TAPE (NORMAL) Adjust audio generator to 18 kHz while maintainlng the same output level. Record and play back the 18 kHz tone and adju

16、st SVR201(L) and SVR202(R) to the samo level as the 1.2 kHz signal. / Tolerance: +I dB . WARNING: If the RIP head is worn, the tape may not have adequate contact with the head, resulting in severe drop outs. A worn head will make this adjustment very difficult or impossible. DO NOT try to adjust the

17、 worn RIP head. Leave SVR2Ol and SVR202 in the factory preset condition, or f they have already been adjusted, readjust them to their approximate mldposition. 11. FREQUENCY RESPONSE TYPE ll TAPE (Cr02) Insert a type 1 1 tape and set selector to type U posltion. Adjust audio generator to 1.2 kHz and

18、12 kHz and repeat process described in step 9 using SVR303(L) and SVR304(R) to adjust both channel simultaneously. ARer 1.2 kHz and 12 kHz are adjusted properly, set audio generator to 20 kHz and repeat same process as described in step 10 while adjusting SVR203(L) and SVR204(R) to obtain correct re

19、ading. I FRONT PANEL from rear side Adjust the semi-variable resistor (SVR851) on the ALIGNMENT COMPONENTS LAYOUT Flg. A FOR ADJUSTING TAPE SPEED CASSETTE MECHA. I # capstan motor PCB through this hole. MECHA. 1 CONTROL Flg. C MAIN PCB IC 701 12. FREQUENCY RESPONSE TYPE IV TAPE (METAL) Insert a type

20、 IV tape and set selector to type I V positlon. Repeat procedure aa In step 9 while adjusting SVR305(L) and SVR306(R) for correct 12 kHz level In both channele. Set audlo generator to 20 kHz and repeat process as In step 10 while adjustlng SVR205(L) and SVR206(R) for correct 20 kHz record level. P C

21、 8. V R 8 5 l Q G f 13. DYNEQ Engage record and pause mode. Adjust audlo generator to 14 kHz and output so that tape recorder output is -5 dB from Dolby NR level (approximately 280 mV RMS). Set tape selector to type I posltlon and connect VrVM probe to test polnt MP201-3(L) (nearest rear panel) and

22、adjust SVR207 from fully counter- clockwise posltlon until the output on the probe decreases 1 dB. Connect VrVR probe to test point MP201-1(R) (nearest to front panel) and adjust SVR208 from fully counter-clockwise position untll the output probe decreases 1 dB. 14. CAR INPUT MONITOR is in position,

23、 frequency 1 kHz SIGNAL to LINE INPUT. AdJust S.G, output so that voltage at TP003, TP004 are 22 mV. CAR Is IN posltion. adjust SVR101 and SVRlO2 to increase 6.0 dB at TPO03. TP004. Tolerance: f 0.5 dB Flg. B FOR ADJUSTlNQ AZIMUTH R / F HEAD FRONT VIEW IRCA JACK I SVRIOI 0 c Aa ICOMPRESS) lEST POINI

24、S REG LEVEL u u SVROO3 1P003 006-OOL8Y l.P(REC1 TPOOS-.-.-GNO 00 000 MPZOI-.-BIAS TRAP AJ 5: a a 5 E a ROW2SVRg PLAY EP DYtIEO. ADJ PLAY LEVEL IPIOI.IOZ -.FINEBIAS EFFECT HEASVREMENT1.P $ $ z =I z OOLBY NR PLAY TRIM MONlTOR FINE TAPE SELECTOR SW VR SW BIAS SW VR www.freeservicemanuals.info21/10/2013Worldwide electronic heritage manualswww.freeservicemanuals.info21/10/2013Worldwide electronic heritage manuals