StageAccompany-Bluebox-spk-sm维修电路原理图.pdf

《StageAccompany-Bluebox-spk-sm维修电路原理图.pdf》由会员分享，可在线阅读，更多相关《StageAccompany-Bluebox-spk-sm维修电路原理图.pdf（50页珍藏版）》请在收音机爱好者资料库上搜索。

1、 This manual contains confidential information. An farm of du lication is rohibited! RadioFans.CN 收音机爱 好者资料库 BLUE BOX SERVICE MANUAL 1 Safety and warranty 1.1 Safety -Warning lnside the PMS 5000 amplifier module, AC voltages up to 240 V may be present! -Connection to the mains voltage The PMS 5000 a

2、mplifier module chassis is connected to ground by the grounding conductor in the power cord. To avoid electrical shock, plug the power cord into a properly wired receptacle. When this ground connection is not present or interrupted, all accessible parts of the amplifier can cause an electrical shock

3、. -Fuses To avoid fire hazard, only replace fuses by the same type and value. -Maintainance Do not perform internal maintainance or adjustments unless there is someone present, capable of rendering first aid and reanimation. Try to perform all service works with mains power off. Remove mains connect

4、or to be sure that no internal voltages are present. 1.2 Warranty SUMMARY Stage Accompany warrants to the original commercial purchaser of each new Stage Accompany product, from the date of purchase by the original purchaser until the end of the warranty period, that the product is free of defects i

5、n materials or workmanship. WARRANTY PERIOD warranty period on all Stage Accompany products is five years the date of the first consumer purchase. with the exception of: all electrical products: three years trom the date of the first consumer purchase; cone assemblies in the loudspeaker and diaphrag

6、ms in the Compact Drivers: one year trom the date of the first consumer purchase; The trom - - page: date: issue: 03-05-1989 1 RadioFans.CN 收音机爱 好者资料库 BLUE BOX SERVICE MANUAL movable parts, such as castors, locks, handles, hinges, fans, etc: oe year trom the date of the first consumer purchase: comp

7、uters and associated peripherals: six months trom the date of the first consumer purchase. - - HOW TO VALIDATE THE WARRANTY To validate warranty, fill out the enclosed warranty card and return it to Stage Accompany within ten days of the purchase date. The purchaser must always keep the original bil

8、lof sale to establish the date of purchase. ITEMS EXCLUDED FROM WARRANTY Appeal on warranty will be voided in case: - of defects caused by influence from the outside, accident, misuse, neglect or influence of water; - the serial number on the warranty and/or product has been defaced, altered or remo

9、ved; - of damage due to shipment; - of damage resulting from neglection of instructions listed in the user manual; - of damage caused by incorrect, abnormal or abuse during delivery; - the unit has been repaired (or shows signs of repair) by someone not authorised by Stage Accompany; - if the warran

10、ty registration card has not been returned to Stage Accompany within 10 days of purchase; - the original billof sale can not be presented whenever warranty service is required; WHAT WE WILL DO Shipment of the product to a Stage Accompany dealer is at the risk and responsibility of the customer. Stag

11、e Accompany will par all labour and material expenses for all repairs covered by this warranty. Stage Accompany will not par the oost of shipment to the Stage Accompany dealer or to the factory. However Stage Accompany will par the return shipping charges if repairs are covered by the warranty. page

12、: 3 date: 03-05-1989 issue: 1 BLUE BOX SERVICE MANUAL CAUTION Warranty work can only be performed at our authorised service centers or at our factory. Every repair or attempted repair by a non authorised party will void the warranty. Stage Accompany reserves the right to alter specifications without

13、 prior notice. page: 4 date: 03-05-1989 issue: 1 BLUE BOX SERVICE MANtJAL 2 Description of the Blue Box The Blue Box is a microprocessor controlled, activ4 system, consisting of: SA 4525 enclosure, SA 8525 high frequency driver, SA 2527 horn, SA 1503 low frequency driver and PMS 5000 amplifier modul

14、e. The system comprises the following features: All the electronic functions are monitored and controlled by the microprocessor. External control is possible through SAnet. one in every horizontally mounted handle. Next remove the flightcase trom the box just by pulling it off the Blue Box enclosure

15、. Fig 1 The module is attached to the chassis with 8 bolts, 4 on each side. Remove these bolts and use the handles of the module to lift the module approx. 20 cm out of the enclosure. Disconnect the loudspeaker connectors and the flat cable. Now the module is free of connections and can be fully pul

16、led out of the enclosure. date: 03-05-1989 issue: 1 Removing the amplifier module BLUE BOX SERVICE MANUAL To remove the loudspeakers (fig 2), place the Blue Box on its back. Remove the lid of the flightcase, remove the foam front (by pulling it of gently) and remove the mounting bolts of the speaker

17、 or driver rou want to replace. Now the loudspeaker can be pulled out. In case the speaker is jammed, use a lever (a screwdriver for example). Disconnect the wires from the loudspeakers terminals. Do not use the Blue Box tor sound reinforcement purposes if one of the loudspeakers is removed! Before

18、re-assembling, connect the red and yellow wires to the red terminal and the black and white wires to the black terminal. I Fig. 2 Frontal view date: 03-05-1989 issue: 1 BLUE BOX SERVICE MANUAL 5 Basic operation of the electronics This chapter describes some of the key circuits of the PMS 5000. The c

19、omplete circuit drawings can be found on page 16 to 29. 5.1 The analog board The analog board contains the electronics for the input amplifier, a rumble filter, the crossover, the amplifier attenuators and the RMS/peak to DC converters. The input amplifier. The amplifier trimmed with TR1. See The in

20、put impedance is Fig 3 The input is equiped with two relays. Rell reverses the input polarity while Rel2 switches to the unbalanced input configuration. Af ter debalancing the input, low frequency rumble is removed with a 24 dB/oct bessel filter at 23 Hz (IC2). IC3 and IC4 split the input signal int

21、o high and low frequencies. The circuit around IC3 is a 24 dB/oct high pass Bessel filter and the circuit around IC4 a 24 dB/act low pass Bessel filter. The amplitude of each of the two signals are controlled by IC7 and IC8. These are digitally controlled attenuators (fig 4). page: date: issue: 10 0

22、3-05-1989 1 differential straightforwardisopamp a amplifier provides 3 dB gain. Common mode rejection can be 36 tor the exact adjustment procedure. over both input legs. tor a page 30 ka Input amplifier BLUE BOX SERVICE MANUAL Fig 4 The digital code presented to D7.DO attenuation and given by the fo

23、rmula: where n is the decimal value of the digital code. The analog board also contains 6 electronic rectifiers. Four of these are peak to DC converters, the other two RMS to DC converters. The pur pose of these rectifiers is to pass the amplitude information on the input and output voltages to the

24、microprocessor. The basic configurations of the two convertersare shown in fig. 5. In each converter the input signal is double-sided rectified. The peak rectifier (upper circuit) stores the information through a diode in a capacitor (instant attack, slow decay). The RMS rectifier (lower circuit) sl

25、owly charges and discharges a capacitor in the negative feedback loop of an opamp. 11 03-05-1989 1 page: date: issue: Digital attenuator determines the level of A - 20 * log 256 BLUE BOX SERVICE MANUAL HAJ1 a.rrPJr Fig 5 electronic rectifiers 5.2 The digital board The digital board contains a microp

26、rocessor circuit, a multiplexer, an AD converter, the SAnet driver and interface electronics for displays and buttons. The processor circuit (see page 20) contains an Intel 8344 uP, an address bus decoder (IC20), a 256K EPROM (IC21) and a 8K RAM (IC22). IC25 is a watchdog that disables the write pro

27、cedure tor the RAM in case the power supply is running down. The remaining part of the digital circuit is found at page 21. The AD converter is built around IC15, IC16, IC17 and IC18. IC17-C and IC17-D are buffers tor the temperature sensors. IC15 is an analog multiplexer which selects the source th

28、at has to be converted. Possible sources are: hot input voltage (dc in 1) cold input voltage (dc in 2) high frequency peak output level (dc hf peak) low frequency peak output level (dc lf peak) high frequency rms output level (dc hf rms) low frequency rms output level (dc lf rms) high frequency ampl

29、ifier temperature (hf temp) low frequency amplifier temperature (lf temp) high frequency amplifier dc (dc high) low frequency amplifier dc (dc low) - - - - page: 12 date: 03-05-1989 issue: 1 ICI-f PEAK I;11-8 BLUE BOX SERV I CE MANUAL The derived values are used to calculate output power, temperatur

30、e, signal present etc. The actual convers ion takes place in IC16. In conjunction with IC17- B it produces a DC voltage which is compared to the DC value of the source (selected by IC15). Comparator IC18 telIs the processor which voltage is higher. In 8 steps the microprocessor tries to make the out

31、put voltage of IC17-B as close as possible to that of IC17-A (successive approximation) and at that time the bit value of IC16 represents the digital value of the source voltage. ICl2 is the SAnet interface. This is a single chip RS422 driver. ICl. .IC3 are the display drivers, IC4.IC7 drive LEDs an

32、d relays. IC9 transfers the button information to the data bus. 5.3 The preamp board The preamp board contains the electronics to drive and correct the power amplifier. The basic electronics of the poweramp driver are shown in figure 6. Fig 6 page: date: issue: 13 03-05-1989 1 drivercircuit BLUE BOX

33、 SERVICE MANUAL T14 forms a current source together with R17 and ZDl. The collector current is ! 12 mA. This source provides drain current for the dual fet Tl. The input of the amplifier is connected to the gate of the left fet, the feedback network to the gate of the right one. In a steady situatio

34、n both input and feedback voltages are CV so both the gate- drain voltages are equal. The current of T14 will be equally divided over the two fets, so 11 - 12 - 6 mA. 11 passes a current mirror composed with R8, D3 and T7. 12 passes two current mirrors, one composed with D3, R9, and T6 and the other

35、 with T11 and T12. In a steady situation 11 - 12 so all current pushed out of T7 is pulled into T12 and both the drive currents will be zero. With a rising input voltage, 11 becomes larger than 12, and not all the current produced by T7 can be pulled into T12. The residual current will be pushed int

36、o the power amplifier as drive current. With a negative input voltage, 12 is larger than 11 and drive current will be pulled out of the power amplifier. DC stability is achieved by the circuit around IC1. To detect DC offset, the power amplifiers output signal is integrated and fed into the feedback

37、 loop. 5.4 The poweramp board Fig. 7 shows the basic setup of the power amplifier. -BOV / ., . Fig page; .L6% date: 03-05-1989 issue: 1 power amplifier BLUE BOX SERV I CE MANUAL The driver circuit provides two signaIs, drive + and drive -. The positive drive current is boosted by T6 and T7 and fed t

38、o the NPN power transistors T12.T14. The negative drive current is boosted by T5 and T8 and fed to T9.T11. T2 is set as a constant voltage source and provides the bias current tor the amplifier. Current limiting is handled by T3 and T4. When the current drawn trom the amplifier rises, the voltage ac

39、ross R26 and R27 rises too. As soon as this voltage reaches a value of ! 0.65 V, T3 and T4 start to conduct and limit the drive current tor the power stage. Current limiting is depending on the output voltage. At 0 V output the maximum current is ! 3 A rising to ! 12 A at 50 V. The regulated power s

40、upply board5.5 The regulated power supply provides 6 different low power voltages tor both the preamplifiers, all relays and the digital circuit. First there are two 80 V voltages to feed the power amplifiers driver circuits. Fig 8 high voltage regulator In this circuit (fig 8) T5 is the regulating

41、transistor. lts base is fed by a current source built around Tl, R6, Dl and D2. The base current is regulated by T8 which senses the output voltage through VAl. With VRl the output voltage can be set. Current protection is arranged with T7. With increasing output current, the voltage drop across R8

42、increases and T7 starts deflecting T5s base current. The negative 86 V supply is built in exactly the same war. The 18 V supplies are straightforward, consisting of two integrated circuits. The 5 V digital supply is extended with transistor T14, allowing larger currents. The unregulated voltage (10

43、V) is used as relay supply. page: date: issue: 15 03-05-1989 1 BLUE BOX SERV I CE MANUAL 5.6 The high power supply board Both power amplifiers share a common power supply which delivers 4 different voltages: two high power 85 V voltages tor the amplifiers power stage and two low power 90 V voltages

44、tor the driver transistors. The high power voltages are rectified by a high power rectifier bridge which, tor dissipation reasons, is mounted on the chassis. The energy is stored in two 22 mF / 100 V capacitors. The low power voltages are on board rectified and the filter capacitors are placed on to

45、p of the high power voltages. All capacitors are discharged by resistors when the power has been switched off. The power supply board also contains a relay that connects the mains voltage to the primary windings of the transformer. 16 03-05-1989 1 page: date: issue: analog board DAc:.e11 PAGG 22 pre

46、amp board !J d$ .cm I ti:) I 0+ -CE - I tI) Q W ( -*-1 l _I !J - -IIIm- -man- () .cm) -(mD- I 9f:! I aD blbl IJ W -!J- I Sf:! .I 1n:J1 =J- IJ -JJ- ill- ill -=J- j -=- -Kj- -cm- .amJ. mij- I aT:! I .:E.r:mJ. r-;-1 I Ef:! I -cm- 0 I i i:) I I i:) -b -cm- CE :Em 0 I iN:) I 80 $00 !J$ -cmD- -CmJ- 1s:J)

47、:R:J- r;1 -rm- I s:J I -CE- 0 wrnH j w CE:J-w 0 0 0 Q) Od P4 ro dO Q).Q. + ro r-fr-f P4 tQOP4 Q) f/J -D rJ ui !. Cl. m i II . I 6 l!m! :. p, p, f/J H Q) ) 0 p, C a .p 11(,2 :;ja a11 MP. ,iD,i,i,i,iD,i :J:J MI d 0 ,q M Pt Pt :J 00 . Q) ,1) ) .!) 0 Pta.:. ll . Q D i !. I I !I c d H 110 ot) Q) d Q)11 o

48、-i . ! t II!I 0 w BLUE BOX SERV I CE MANUAL 7 Basic operation of the software chapter explains is touched or a This button DiSPlay selectl With this button, the contents of the 7 segment displays can be selected. There are 4 possible selections: input level (attenuation in dB), indicated by temperat

49、ure (in degrees Celsius), indicated by peak power (in Watts), indicated by L3 ave rage power (in Watts), indicated by L4 - Each item can be monitored tor the high and low frequency amplifier separately (selected at readout select). Depressing display select tor more than 1 second activates the lock function. The lock code can be selected with the up/down buttons. Depressing display select again accepts the selected code and locks the PMS 5000. Unlocking requires the same procedure. These fun