Realistic-STA235-rec-sm 电路图 维修手册.pdf

《Realistic-STA235-rec-sm 电路图 维修手册.pdf》由会员分享，可在线阅读，更多相关《Realistic-STA235-rec-sm 电路图 维修手册.pdf（40页珍藏版）》请在收音机爱好者资料库上搜索。

1、t V STA.235 AM IFM STEREO Catalog Number: RECEIVER 31-2065 cusToM MANUFACTURED FoR RADIo sHAcKIn DrvrsroN 0F TANDv coRpoRATroN I RadioFans.CN 收音机爱 好者资料库 CONTENTS PAGE 1. SPECIFICATIONS 3- 4 2. BLOCK DIAGRAM . 5 3. DISASSEMBLY INSTRUCTIONS . 6 4. DIAL STRINGING DETAIL . 6 5. ALTGNMENT PROCEDURE . . 7

2、 - I 6. ALIGNMENT POTNTS . . 10 7. LEVEL DTAGRAM . 11 8. TROUBLESHOOTTNG . 12- 19 9. 5030 EO AMp BOARD . . 19 10. 0042 TUNER BOARD . 20 11. OO43 TONE AMP all units should be able to approximate these-some will exceed and some may drop slightly below these specs. Limit Specs represent the absolute wo

3、rst condition which stiil might be considered acceptable; in no case should a unit perform to less than within any Limit Spec. BLOCK DIAGRAM I surlYlds ts r +vl 9 55 E ss E9HS3P; = =oA TJ-JTJ- * =?=ir : =-;IS =E D!SASSEMBLY I NSTRUCTIONS 1. Removing chassis from Wooden Cabinet. (Refer to the Fig. A.

4、) Remove five screws-two (BB) from each side of the wooden cabinet and one(89) from the back. 2. Removing the front Panel. (Refer to the Fig. A.) Remove six screws-three (89) from each side of the Front Panel and remove panel. 6B-_ ) -aq o* Fig. A DIAL STRINGING DIAGRAM Note: Tuning capacitor should

5、 be in fully closed position NO SHAFT DIAL DRUI,/ ALIGNM ENT PROCEDURES Do not attempt alignment unless the following equipment is available. 1. AM Signal Generator 2. Oscilloscope 3. AC Voltmeter Note: Remove line cord antenna from FM external antenna terminal when aligning. AM IF ; :,.:ir:1r:it t:

6、, t VR6O1aL203 Figure 4 vR601 b 10 LEVEL DIAGRAM FILTER FILTER z. z. (9 U (, F J o FREOUENCY : 1 KHZ INPUT SELECTOR 6 E st + (Low) | 2.5mV I 11 TROUBLESHOOTING SymptomCause and Remedy 1 ) Receiver not operative: Pilot lamp does not light. A) Faulty AC power cord Replace the cord. B) Defect in the po

7、wer switch Replace the switch. C) Broken wire in the power transformer Rep lace the transformer. D) Broken power fuse Replace the fuse. 2l Fuse blows when power is turned on. A) Power Transformer T851 defective Replace the transformer. B) Short in the primary or secondary of the trans- former circui

8、try Repair the short. C) Damaged rectifier D807 Replace the damaged rectifier. D) Short circuit in the rectif ier circuit Repair the short. E) Short circuit in the power transistor TR608a, b or TR609a, b Replace the defective transistor and check circuit. 3) Pilot lamp does not light.A) Defective la

9、mp Replace lamp. B) Disconnection in the transformer T851 tertiary winding Replace the transformer. 4lPilot lamp lights but no sound from both channels. Resistor R814, R809. R923 or R924 open Replace. Capacitor C803, C804, C805, C812, C813, C851, C852, C916 or C917 defective Replace the defective ca

10、pacitor(s). Diode D807 damaged Replace the diode. Open in secondary winding of the power trans- former T851 Replace the transformer. Transistor TR804 or TR806 open Replace the transistor(s). Diode D802, D804 or D805 damaged Replace the damaged diode(s). Defective D801 or D803 Replace the defective d

11、iode(s). A) B) c) D) E) F) G) 12 Symptom Cause and Remedy H) Transistor TR803 defective Replace the transistor. l) Defective R802, R803, R804, C801 or C802 Replace the defective component(s). J) Defective Relay RL801 Replace. 5) A Speakers do not work.A) Speaker switch 51 defective Replace the switc

12、h. 6) B Speakers do not work.A) Speaker switch 51 defective Replace the switch. 7lOne channel does not work with VOLUME at maximum with a test signal applied to the center terminal of VOLUME control VR951 of the dead channel. A) B) Defect in transistor TR901, TR902 or TR903 of TONE AMP BOARD OO43 Lo

13、cate and correct the defect. Defect in transistor TR601, TR602, TR603, TR604, TR605, TR606, TR607, TR6O8, TR609 or TR610 of MAIN AMP DRIVER and MAIN AMP BOARD 0045 Locate and correct the defect. C) Break in copper foil of printed circuit board 6044, 0043 or 0045 Repair or replace circuit board. Shor

14、t in speaker output terminal Repair the short. Defective resistor R901, R902, R903, R904, R905, R906, R907, R918, R919, R920, R737, R738, R742, R602, R603, R604, R605, R606, R607, R608, R609, R610, R612, R613, R614, R615, R616, R625, R626, R621 or R622 Replace the defective resistor(s). D) E) 8) Sam

15、e as 7 above but channel operates when test signal is applied as 7. A) Defective SELECTOR switch 52 or TAPE MONITOR 1 and2 switches 53, 54 Repair or replace the switch(es). 9) Speaker works normally but headphones do not work. A) Headphone plug does not mate with jack Replace the plug. B) Defective

16、resistor R651a, b Replace the resistor(s). 10) All inputswork normally except for AUX input. Poor contact in AUX input jack Repair or replace the jack. Faulty SELECTOR switch 52 Repair or replace the switch. A) B) 13 SymptomCause and Remedy 11) PHONO input not operativeA) Defective 1C501 Replace the

17、 lC. B) Faulty resistor R501, R502, R503, R504, R505, R506, R507 or R508 Replace the faulty resistor(s). C) Faulty capacitor C501, C5O2, C503, C504, C507 or C508. Replace the faulty capacitor(s). D) Poor contact in PHONO input jack Repair or replace the jack. E) Faulty SELECTOR switch 52 Repair or r

18、eplace the switch. 12) TAPE MONITOR 112not operative A) Defective contact in TAPE MONITOR 112 OUT jack Repair or replace the jack. 13) FM does not operate.A)Transistor TR808 damaged (open) Replace the transistor. Defective resistor R81 6 Replace the resistor. Short circuit in TUNER B+ circuit Repair

19、 the short. Poor contact in SELECTOR switch 52 Repair or replace the switch. Resistor R301 defective Replace the resistor. Choke coil L2O2 defective Replace the choke coil. Capacitor C301 defective Replace the capacitor. Defective lC 1C201 or lC2O2 Replace the defective lC(s). Defective IFT T101 or

20、Coil L203 Replace the defective component(s). Defective resistor R201, R203, R204, R205, R216, R217, R218, R221, R222, R225 or R232 Replace the defective resistor(s). Defective capacitor C111, C112 or C2O1 Replace the defective capacitor(s). Defective transistor TR101 ,TR1O2, TR103 or coil 1101-L105

21、 of TUNER BOARD 0042 Replace the defective component(s). Faulty lead-in Repair or replace the lead-in. B) c) D) E) F) G) H) t) J) K) L) M) 14 SymptomCause and Remedy 14, Poor multiplex separationA) lmproper adjustment Readjust T101, VR301 and VR302. (Refer to MPX ALIGNMENT on page g.) B) Transistor

22、TR301, TR302, TR303 or lC 1C301 of TUNER BOARD OO42 defective Replace the defective component(s). C) Variable resistor VR301 or VR302 defective Replace the defective variable resistor(s). 15) Stereo indicator does not light.A) Defective indicator LED D756 Replace the LED. B) lmproper adjustment of V

23、R301 of TUNER BOARD oo42 Make readjustment. (Refer to MPX ALIGNMENT on page 9.) C) Defective lC 1C301 or resistor R327 Replace the defective component(s). 16) FM volume not sufficentA) lf volume of both L and R channels not enough: Front-End defective, or faulty I FT T101 or diode D2O7, D208 or faul

24、ty lC lC2O2,lC301 or capacitor C219 of TUNER BOARD 0042 Locate and replace the defective component(s). B) lf sound of one channel not enough: Defective LPF301 or TR302 (PCB 0042) in case of L channel, or defective LPF302 or TR303 (PCB 0042) in case of R channel Replace the defective component(s). 17

25、l. AM does not operate.Damaged either 1C401 or TR404 of TUNER BOARD OO42 Replace the damaged component(s). Def ective L4O1 , L4O2 or C F401 of TU N E R BOARD OO42 Replace the defective component(s). One of resistors of TUNER BOARD 0042 defective Replace the defective one. One of capacitors of TUNER

26、BOARD 0042 defective Replace the defective one, SELECTOR switch 52 defective Repair or replace the switch. Defective Tuning Gang Replace. Damaged AM bar antenna Repair or replace bar antenna. A) B) c) D) E) F) G) 15 SymptomCause and Remedy 18) LOUDNESS has no effect.A) Defective LOUDNESS switch 57 R

27、eplace the switch. B) Defective capacitor C731 or resistor R735 Replace defective component( s). C) Defective VOLUME control VR951 Replace. 19) STEREO-MONO not effectiveA) Defective MONO switch 56 Replace the switch. 2Ol TAPE MONITOR 1 or 2 not effective. A) Defective TAPE MONITOR switch 53 or 54 Re

28、place the defective switch(es). B) Poor contact in TAPE MONITOR 1 or 2lN jacks. Repair or replace jack(s). 211, BASS control has no effect.A) VR903 defective Replace. B) Defective capacitor C910, C91 1, C912 or resistor R913, R914, R917 of TONE AMP BOARD 0043 Replace defective component(s). 221 MID-

29、RANGE control has no effect. A) VR902 defective Replace. B) Defective C908, C909, R911, R912 or R916 of TONE AMP BOARD OO43 Replace the defective component(s). 23, TREBLE control has no effect.A) VR901 defective Replace. B) Defective C906, C9O7, C909, R910 or R915 of TONE AMP BOARD OO43 Replace the

30、defective component(s). 241, Excessive noise with PHONO input A) Faulty 1C501 Replace the lC. B) Faulty R501, R502, R503, R504, R505, C501 or c503 Replace the faulty component(s). 251 Noisy VOLUME controlA) Defective VR951 Replace the variable resistor. B) Defective capacitor C508, C901, C9O4, C914

31、or c602 Replace the defective capacitor(s). 26l. SIGNAL meter not functioningA) Defective meter Replace the meter. 16 * t* A tri SymptomCause and Remedy B) ln case of FM reception, R226, C210, C223, C251 , D203 or D204 defective Replace the defective component(s). C) ln case of AM reception, VR401 ,

32、VR4O2, D401, TR401 or TR4O2 defective Replace the defective component(s). 271 AUTO-Magic AFC has no effect when AUTO-M switch is ON. (White light behind the tuning meter does not change to red when the tuning control is touched.) A) Transistor TR701 ,TR7O2 or 1C701 defective Replace the defective co

33、mponent(s). B) Resistor R701-R718 defective Replace the defective resistor(s). C) Diode D701 or D702 defective Replace the defective diode(s). D) Capacitor C701-C704 defective Replace the defective capacitor(s). E) Defective switch S10 Replace. F) Defective AUTO-Magic indicator lamp PL4 Replace the

34、lamp. 28) White light does not light when the tuning control is released. A) Defective transistor TR701 (short) f R7O2 (open) or lC 1C701 Replace the defective component(s). B) Defective resistor R703-R718 Replace the defective resistor(s). 29, OUATRAVOX not effectiveA) Defective switch 51 Replace t

35、he switch. 30) TONE F LAT has no effect.A) Defective switch 55 Replace the switch. 31) FILTER-LO has no effect.A) Defective switch 59 Replace the switch. B) Defective capacitor C732 Replace the capacitor. 32) F I LTE R-H I has no effect.A) Defective switch 58 Replace the switch. B) Defective resisto

36、r R738 or capacitor C733 Replace the defective component(s). ,:,rrWlDE BAND AM is not functioning. ol (Wh.n this circuit is functioning, hi-gh frequency response (3 tHz and above) will improve with high input signal levels. With input level of 28 mV/m or more, high frequency response should be notic

37、eably better. Use high quality sig. gen. modulated with 3 kHz or 4 kHz. A) Damaged transistor TR401 ,TR4O2 or TR403 of TUNER BOARD OO42 Replace the damaged transistor(s). B) Defective diode D401 Replace the diode. b $, F L. r; 17 Symptom Cause and Remedy C) Damaged transistor TR404 Replace the trans

38、istor. D) lmproper adjustment of VR401 Readjust V R401 . (Refer to AM lF t t 20 range lnformation. OO43 TONE AM P ,lXrl:# 24 TRANSISTOR ; 0.5P 0.0,4p 15P 0.01p 0.04p 0.9,u 0.0,4p 0.02p 1 8P(UJ) 0.04p 7P(TH) 10P 33P 15P 0.0,4p I 00P 0.04p 0.01rt ul, o o,:0, 50 25 50 25 50 25 25 50 25 25 25 50 12 25 5

39、0 25 ,:, t5 +80 -20 t0.5P tb t10 tS +80 -20 t5 +80 -19 t5 tl0 +80 -19 t5 +80 -20 tl0 +80 -20 +80 -20 t10 +80 -20 Ceramic Ceramic Ceramic *: See page 35 for Change lnformation, Ref. No. Value (F) Voltage (v) Toler- ance %l Material c214 c215 c216 c217 c218 c219 c220 c221 c222 c223 c224 c225 c226 c227

40、 c228 c229 c230 c231 c232* c251 c301 c302 c303 c304 c305 c306 c307 c308 c309 c310 c31 1 c312 c313 c3r4 2.2p 0.04p 4.7 p 390P 1p 0.04p lp 0.04p 4.7 p 33p 0.04p 1p 56P 0.04rr 0.01p 12P 47p 330p l0p 360P 1.5p 3.3p 0.047 p 0.22p 2.2p 0.001p ,u, 220P 25 50 25 50 25 16 25 50 25 50 6.3 16 50 35 25 q9 25 50

41、 +75 -19 +80 ti +75 -10 t10 +75 -10 +80 -20 +75 -10 +80 -20 +75 -10 +50 -10 +80 -20 +75 -10 t10 +80 -L0 t5 +50 -10 +50 -10 t5 +75 -19 t10 x20 +75 -19 r l,0 +75 1,9 tl0 Electrolytic Ceramic Electrolytic Ceramic Electrolytic Ceramic Electrolytic Ceramic Electrolytic Ceramic Electrolytic Ceramic Electr

42、olytic Electrolytic Polystyrene Electrolytic Ceramic Electrolytic ueramtc Electrolytic Ceramic 26 Ref. No. Valu e (F) Voltage (v) Toler- ance %t Material c31 5 c31 6 c31 7 c31 B c319 c320 c321 c322 c401 c402 c403 c404 c405 c406 c407 c408 c409 c41 0 c41 1 c412 c41 3 c414 c41 5 c41 6 c417 c41 B c41 I

43、c420 c421 c422 c423 c424 C501 a,b C502a,b C503a,b c504 220P o.1p UsedNot 0.LZp 4.7p 0.01p 1op Not Used 470p ol,ru 4.7 p 0.02p 390P Not Used 0.04p 0.01p 4.7 p o-y,ru 0.039p 3.3p 1p 0.056p 1p 22P 4.7 p 0.04p 47p 3.3p 120P 22p 1 00p 25 25 16 50 50 6.3 25 25 50 7,? 50 25 50 25 16 l6 50 i: t10 +75 -19 ,?

44、9 +75 -10 t10 +50 -10 +50 -10 -1,0 +75 -10 r10 r5 1,0 +75 -10 ,i +75 -19 t10 +75 -10 tl0 +75 -10 t10 +50 -10 +75 -10 t10 +50 -10 Ceramic Electrolytic Electrolytic Ceramic Electrolytic Electrolytic Ceramic Electrolytic Ceramic Ceramic Electrolytic Ceramic Polyester Electrolytic Polyester Electrolytic

45、 Ceramic Electrolytic Ceramic Electrolytic Electrolytic Ceramic Electrolytic *: See page 35 for Change lnformation. Ref. No. Value (F) Voltage (v) Toler- ance %t Material C505a,b C506a,b c507 C508a,b c55 1 c552 c553 c554 c555 c556 C601 a,b C602a,b C603a,b C604a,b C605a,b C606a,b C607a,b C608a,b C609

46、a,b C61 0a,b C61 1a,b C61 2a,b C61 3a,b C61 4a,b c701 c702 c703 c704 c705 C731a,b C732a,b C733a,b C734a,b C735a,b C736a,b 1 500P 5600P 1 00p 0.47p 0.01p 0.056rt 0.22p 0.01p 56P 1p ,o: 10P 1 00p 47p 0.001p 1 99P 0.1p 2P 5P 0.02p 0.47p 10i, 22p 1 00p 0.01rt 0.012p B2OOP ,u, 2.2p q9 16 50 25 50 25 50 3

47、5 25 500 50 99 50 500 50 25 50 16 10 50 25 ,1,0 +50 -10 +75 -10 +80 -?9 - 1,0 t10 +75 -10 +50 -10 i t0.5P +80 -20 +75 -10 +50 -10 r10 +50 -10 t10 +75 -10 Polyester Electrolytic Ceramic Polyester Ceramic Ceramic Electrolytic Ceramic Electrolytic Ceramic Polyester Ceramic Ceramic Electrolytic Polyeste

48、r Electrolytic 27 Ref. No. Value (F) Voltage (v) Toler- an ce (A) Material c801 c802 CB 1O CB1 1 cB12 cB5 1 CB52 c853 c854 c855 c856 c857 c858 C901a,b C902a,b C903a,b C904a,b C905a,b C906a,b C907a,b C908a,b C909a,b C910a,b C91 1a,b C91 2a,b C91 3a,b C914a,b C91 5a,b c916 c91 7 c803 cB04 cB05 47p 4.7

49、 p u:* 0.0,047 p 0.01p 0.47 p 10p 10P 1p 2.2p 1 80P 1 BOOP 3300P 6800P 0.039s 0.033p 3300P 1p 2.2p 10P 220p 330p ,:, los 1 000s 1 000P 25 16 25 50 50 125 ; 50 16 50 25 ?9 25 50 25 +50 -10 +75 -10 +50 -19 +50 -10 t10 t10 t10 +50 -10 +50 1,y t20 +75 -r0 +50 -10 t10 +75 -10 t10 +75 -10 Electrolytic Electrolytic Ceramic Electrolytic Polyester Ceramic Electrolytic ueramrc Electrolytic Ceramic Polyester Electrolytic Ceramic Ele