Uher-4000ReportL-tape-bbc 维修电路原理图.pdf

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1、UHER PORTABLE TAPE MACHINES BBC MODIFICATIONS & SUPPLEMENTARY INFORMATION Author: D.P.E. Brown First issue: February 1978 RadioFans.CN 收音机爱 好者资料库CONTENTS page Introduction 1 Modifications to Type 4000 Report-L 2 Modifications to Type 4000 Report-IC up to 1977 4 Modifications to Type 4000 Report-IC i

2、n 1977 6 Adjustment of Preset Controls on Machines with Modifications up to 1977 9 Adjustment of Preset Controls on 4000 Report-IC Machines with 1977 Modifications 10 Checking Frequency Response 1 1 Checking Erase Voltage 1 1 Motor Electronic Control Circuit 12 Telephone Coupling Unit UN 10/ 17 15 S

3、et in IBM 10 pt Univers Produced by Technical Publications Section Editor LP. Best Printed by The Print Unit, BBC Engineering Training Centre RadioFans.CN 收音机爱 好者资料库Introduction This Instruction describes the modifications that have been made to a large number of the Uher 4000 Report-L and 4000 Repo

4、rt-IC portable tape machines used in the BBC, and includes the setting-up adjustment procedure for such machines. In addition, some supplementary information is given, particularly on the functioning of the motor control circuit and the Telephone Coupling Unit UN10/17, which is used to link a Uher p

5、ortable tape machine with a Post Office line. The modifications are primarily intended to make the machines suitable for (a) providing a low-level playback output which may be used to feed a mixer, and (b) cueing and playback ofer an ordinary Post Office subscribers line. The machines are also modif

6、ied so that they will only operate at 19 cm/s. The 4000 Report-L is no longer made, and was superseded by the 4000 Report-IC, though the former is still widely used in the BBC. Originally the machines were manufacturered in Germany with alterationsto BBC requirements incorporated, but more recently

7、normal production machines have been modified in the United Kingdom. Some earlier 4000 Report-L machines were only modified to provide a low-level output suitable for a mixer: these may be identified by a red dot preceding the engraved letters BBC. Later 4000 Report-L machines, with all the modifica

8、tions, have white dots before and after BBC. For a period, the modifications on the 4000 Report-IC machines were in many respects similar to those on later 4000 Report-L machines, but to satisfy revised Post Office requirements applying to the use of 4000 Report-IC machines connected to telephone li

9、nes, new modifications on these machines were introduced in 1977: the 4000 Reportle machines with these new modifications are marked P.O. Line 11. Except where modifications apply, reference should still be made to the technical information provided by Uher on their circuit sheets and in their opera

10、ting and service manuals for these machines. Modifications to Type 4000 Report-L The parts of the circuit that have been modified are marked by numbers on the circuit diagram shown in Fig. 1. Notes concerning these modifications are given below against the identifying numbers. Some older 4000 Report

11、-L machines, marked with a red spot before the engraved letters BBC, have only modifications 1 and 9. Machines fitted with a 3-pole microphone socket in place of a 5-pole socket, as described in modification 2, may in other respects be unmodified machines. 1. This modification makes the output at co

12、nnector 3 of the RADIO/PHONO socket suitable for applying to a mixer. A resistor in series with a capacitor are added in parallel with R38 to obtain approximately C.C.I.R. equalization, and a fixed attenuator network is added in series with the feed to connector 3 to reduce the output to about -60 d

13、B. lt is assumed that the load across connectors 3 and 2 will be 600 ohms. 2. A 1 : 1 transformer with an electrostatic screen is added at the microphone input. As a result the input impedance is balanced, but unchanged in value. A capacitor is connected in parallel with the primary. The transformer

14、 is mounted behind the front panel, above the input selector switch and recording level control, except in earlier machines in which it is mounted on a bracket behind the microphone socket. As a rule, a 3-pole DIN socket is fitted for feeding a microphone to the transformer, in place of the 5-pole s

15、ocket on a standard machine; with this change the facility for remote control via the microphone socket is omitted. 3. C32 and R46 are omitted, and capacitors and resistors are added in circuit, at the record/ playback switch preceding the output stage. This is in order that, in either the record or

16、 playback mode, the output has a suitable rising frequency characteristic for transmission over a P.O. line. 4. A preset 1 0-ohm resistor is connected in series with the external loudspeaker socket, which is used to feed a P.O. line (via a coupling unit). This resistor is set in the output adjustmen

17、t procedure so that a standard output, suitable for a P.O. line, is provided corresponding to zero level indication on the recording meter (with volume and tone controls set at maximum). The 10-ohm control is mounted inside the machine behind the external loudspeaker socket, or on one side of the RA

18、DIO/PHONO socket. 5. A 750-ohm resistor is connected in series with the variable resistor R19 when it is a 1-kilohm control. This facilitates adjustment of R19 to obtain a standard playback output from a recording made on the machine (after the setting of the 10ohm control previously described). On

19、later 4000 ReportL machines, R19 is 2.5 kilohms and the addition of the 750 ohms resistor has not been necessary. 6. A ganged pair of changeover switchds is fitted so that adequate output is still available to the internal loudspeaker when it is used. The switches are operated by the shaft of the vo

20、lume control. When the knob is pushed in, the added RC networks shaping the frequency characteristic for sending to line are short-circuited, and simultaneously output is fed to the internal loudspeaker instead of to the external loudspeaker socket. In the original circuit, one switch shunts the int

21、ernal loudspeaker across the external loudspeaker socket. 7. The switches in the standard Uher circuit that change resistance and capacitance values in the amplifier with change of speed are omitted; a link is fitted for the fixed speed of 19 cm/s. All the resistors and capacitors required for apeed

22、s other than 19 cm/s are omitted. 8. With the substitution of a 3pole socket in place of a 5-pole socket for the microphone, the facility for remote control is absent. The remote control relay circuit components are omitted and there is no conductor joined to connector 4 on the accessories (6) socke

23、t. 9. C28 and R33 are short-circuited to modify the recording frequency characteristic. 2 foo1li ._ _ .,. _ . ,1 + 2 RADIO/PHONO 0 .B1 1 3 I rw et=-.;-l._ I T 2 R3 .C4 1M .,.200p I I I + . r p 1 - ,- -, . 0 .Ea I . . I 33 K5 + I -3 R661) m-220 T?) 100 _.!L.,_ L,oo N!k 15k) I R38 15k + + 00012: I r I

24、 ro . c.J 001 . +_j r- - . -.-. -. -. I I 0001 r C9 R18 10kl C15 -11-,-) I pf :33p I. = &p .,._.,1-tr )T2 r b R13 I p lam I : r :o = . C12 ;t 16 L _ ! il0 100p , # 6 I R11cord I & Playback Head I -:) : Op R4 2Sk Cf$ + L. _ _ I I I I I . I I I ;- r 1o p 5 R25 T;., ) TT; 47k R2fj 4701 31. !C20 i100 9

25、r-:C28 lfR33 =g oo68 47k R4_l tOOk . 1ok 0068 120 p +- ,Mi., 1o8k 181 r . p - 001 . R71 I 15k - VOLUME R51 10k log :c35 01 R48 )-Tn I .!:,) I I? T5 BC214 I .A I R621 tOOk 181 ,: L _ I TONE + _+ _ j, -6-t 4 . -. - (!)SPEAKER l socket R22 5k l_ neg.log. J l REC LEVEL K2 + -7 - I Switches omittd I t-L-

26、i-ook -. i I c 22 = 0 0 0 0 . I 0012 C24 C27& C29 R37& R41 I RJ,. 10 . I ) mitted omitted I I I 0 .L-: _ J Accessories 6 .-_. _ _, + 1 5 .!9 R68 .ElQ. . -r-=r-=-oKS. 120 51 1,K1-0-, NOTES (1) C41 1000 For additional component details, and circuit differences on earlier machines, refer to the Uher ci

27、rcuit diagram sheet. (The above circuit is valid for serial nos. from 1423148920.) (2) The ten SWitches w1th positions marked r (= record) and p (= playback) are ganged. C43 C44 2000 2000C:J 8 6 to 75V d.c. Fig. 1 Circuit of Uher 4000 Report-L with BBC modifications, (motor control not shown B I! 1:

28、1 + -RAOIO/PHONO -Or-r -.-=1k:J-, _ -_-:_-_,- K1 n + I +I.1 vp lltl1 I,!-L -l .- ,i I 100 12k J 15k R11454k I .-. , + I -. _ :+ +.-. 00012:T L-. : voL I R116ci :;c61 j C109 R +I 22 1ok C117 T I I fm:j ) I R106 1JR111 R1.Q_ 100! R128 1k =C122 I 22k 2-2k .-r . -,._. -, 9 15k ;0033 C110 R115 R12 1 +. r

29、- C25 r-11-C1,.3 5:6k -;c) c1 ._ _ _._ _ _. 22 .6 l R5 I 001 I 10k I c:, C138 I r log -._ 111 100 1Bk -._c-l_l I ()041 ! .1 =:. J : ,_,., 100 /1 1r Jf7 1 + cIJ 2;, -:!, ID-5 . -, :J 1 no; , 47 T10 C115 I -l,-1 1 E3VI -) .-1 I J I f? Ljn._. 5k . T1Dj._ R140 R145 C13 1 .1. c145 T 6 I : I+ I f. 47k 33k

30、 330pc:;:; l I 2 22 ,r L 29 . ;b,; I L ,_ . l _j ,gJ r:= :;: ;:i,.: r 1.-+-1 4 7 k 1 k .1. r r ,B1.27 L: R1-12,j 100k 0 . 47k h10k R153 J 10k I , ltog i G 680 c E_,_I I C14 4 r- _1 R156 10 0 C 139 = C142 1 120 1 0.47 I p R107 ,:1J3 1 :, p p1 R12 . R_13_2-+J-rL_c-1102-03f-_.-k -+ _u C108 391 116 1K R

31、125 0 -0033 120 p PJ.-J-10_0_;-1-_kcrJ-_16_- -4-+2-2-k-i+-E-+-3-3_ _ 4_7_0_._5_ . -r-r-rlp _ _. t+ + I NOTES (1) c3 OCkCt N I :; L. -+-; L:2:0:=-=-=-=-:.-_ =-. =-_j Accoassorioas K4 (gand with K10l (rx;:;-:)11-.- Erasoa . + Hoaad 1 _ 1 I C102. I (JI TIO I 0005 .01l._IL-I-+- I R11 I %IF= . L _ R119 T

32、108 R118 680k :loC116 0022 -KEi 1., 5 :_C124 jjj0022 R137 I 1k R147 47 C132 !._ 47 c:; 15k (p(4 0!, I -+-c/tr K7 -6to75V C126 JD-.c$J1t-1n-, l -AL 1 +2 L-0-l . _ _j Fig. 3 Circuit of Uher 4000 Report-IC with BBC 7 modifications in 1977, (motor control not shown). Adjustment of Preset Controls on Mac

33、hines with Modifications up to 1977 This is the procedure applied to 4000 Report-L and 4000 Report-IC machines with modifications made up to 1977. Component reference numbers for the 4000 Report-IC are given, followed in brackets by numbers for the 4000 Report-L. 1. Switch the machine to the recordi

34、ng mode. On a 4000 Report-IC, set the ALC selector switch to 0. On a 4000 Report-L, set the input selector to its central, radio source, position. 2. Apply a 1-kHz signal at a level of -40 dB to connectors 1 and 2 (earthy) on the RADIO/ PHONO socket. 3. Adjust the recording level control to obtain a

35、n output of -1 dB between connectors 2 and 3 (earthy) on the accessories socket ( 6) when measured with an EP14/1 (or ATM/1) set to high input impedance (i.e. about 50 kilohms). 4. Adjust the meter sensitivity control R148 (R11), inside the machine, so that the recording level meter reads zero level

36、. 5. Pull out the volume control knob. Turn the volume and tone controls fully clockwise. 6. Connect a 3.9-ohm load to the external loudspeaker socket and adjust the 1 0-ohm internal preset control in series with this socket to obtain -11 dB across the load. 7. Turn the preset control R103(R4) to fe

37、ed maximum bias to the recording head (i.e. set the control to minimum resistance). 8. Record a 1-kHz input for about 10 seconds under the conditions set up in steps 1 to 4, i.e. with the recording level meter reading zero level. 9. Play back the recording with the controls set as in step 5 and adju

38、st the 1-kilohm preset control fitted in place of R122 (or adjust R19 in a 4000 Report-L) so that -11 dB is obtained again across a 3.9-ohm load at the external loudspeaker socket. 9 Adjustment of Preset Controls on 4000 Report-IC Machines with 1977 Modifications 1. Switch the machine to the recordi

39、ng mode, set the ALC selector switch to 0 (manual), and press in the tone control knob. 2. Apply a 1-kHz signal at a level of -40 dB to connectors 1 and 2 (earthy) on the RADIO/ PHONO socket. 3. Adjust the recording level control on the front panel to obtain an output of -1 dB between connectors 2 a

40、nd 3 (earthy) on the accessories socket ( 6) when measured with an EP14/1 (or ATM/1) set to high input impedance (i.e. about 50 kilohms). Note: As a rule, this should result in the recording level control being adjusted to about half its range of rotation. 4. Set the meter sensitivity control R148,

41、inside the machine, so that the recording level meter reads zero level. 5. Pull out the tone control and volume control knobs. Turn both these controls fully clockwise. 6. In steps, increase the recording level control on the front panel, and readjust the 500-ohm preset control connected within the

42、machine to the recording level control to maintain -1 dB at the accessories socket (corresponding to zero on the recording level meter), until the recording level control is fully clockwise. This is done in steps to avoid damaging the meter. 7. Connect a 4-ohm load (a 3.9-ohm resistor may be used )

43、to the external loudspeaker socket and connect an EP14/1 across this load. Adjust the 10-ohm internal preset control associated with the loudspeaker socket to obtain -13 dB across the load. Alternatively, plug a UN10/17 coupling unit into the external loudspeaker socket and adjust the 10-ohm preset

44、control to obtain +2 dB across a 600-ohm load at the output of the coupling unit. 8. Turn the preset control R103 to minimum resistance so that it feeds maximum bias to the recording head. 9. Using the same 1-kHz signal as before (i.e. giving -1 dB on an EP14/1 at 2 on the accessories socket), make

45、a recording on tape on the machine for about 10 seconds. 10. Play back the recording with the tone and volume control knobs pulled out and turned fully clockwise. Adjust the 1-kilohm preset control fitted in place of R122 so that -13 dB is obtained across a 4-ohm load at the external loudspeaker soc

46、ket (or +2 dB across a 600-ohm load at the output of a UN10/17 plugged into the external loudspeaker socket). After the above adjustment procedure using 1 kHz tone, connect to the machine the microphone that will normally be employed with it and readjust the 500-ohm preset control (previously set in

47、 step 6) as follows: 1. Check that the ALC selector-switch is set at 0 and that the front-panel recording level control is fully clockwise. Ensure that the tone and volume control knobs are pulled out. 2. Operate the machine in the recording mode and, holding the microphone at a normal distance (say

48、, 450 mm), readjust the 500-ohm preset control so that typical spoken passages cause the recording level meter to just indicate zero level at peaks of deflection. 10 Checking Frequency Response 1. Demagnetize the heads. 2. Play a BBC 19-cm/ standard frequency-response tape on the machine and measure

49、 the response at all frequencies into a 600-ohm load between connectors 3 and 2 (earthy) on the RADIO/PHONO socket. 3. Using a reel of new tape, make a recording on the machine at the same frequencies as on the BBC frequency-response tape. Feed the recording input, from an audio generator, to connec

50、tors 1 and 2 (earthy) on the RADIO/PHONO socket at a level of about -40 dB. Set the recording level control to obtain a reading of -12 on the meter of the machine with a 1 kHz input, then note the audio generator output and maintain this output at all the other test frequencies. 4. Replay the record