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1、1 Operators IC7c has 30dB of gain, which enables D21-D30 to turn on 30dB ahead of D31- D40. Q2 provides a regulated power source for the LM3915s; Q3 and Q4 are constant current sources for the LED chains. To calibrate the meter, a signal of 0dB is applied at pin 1 of ST6 the level can be externally
2、verified at whichever output is driving the meter, selected by the meter changeover switch SW3, and the cathode of D15 is monitored by an os- cilloscope. When a symmetrical trace is obtained by adjusting VR4, VR5 is adjusted so that D33 the 0dB yellow LED just illuminates. Then the signal is reduced
3、 to -30dB, when the LED chain should have only the first three LEDs D21-D23 illuminated. If the calibration appears to be wrong, the symmetry should be rechecked. Pre fade routing. The required pre-fade signal as selected by SW3 is fed via ST6 Pin 2 to the matrix level board. Here it is presented to
4、 a DG211 quad analogue switch IC1 configured as a ?T? switch for maximum off isolation. As with the matrix group mix buss input, the channel is assigned to a pfl channel corresponding to the module location in the main frame. This is accomplished by inserting the appropriate jumper in ST5/6. 25 The
5、pfl select lines are distributed along the same ribbon cable as the mix lines and enter the module via ST2 pins 12 thro? 19. These select lines are normally high +15V. They are brought to 0V to enable the channel pfl output. When enabled, the channel pfl output appears on the pfl mix buss via ST2 pi
6、n 10. Switch LED powering. The status LEDs are powered by the current source based around Q1. The order for the chain starting from Q1 is main mute, meter changeover & matrix mute on the main board. It then loops via ST6 pin 17 to the sub board. From here it goes to the matrix on/off switches 1 thro
7、? 8. The chain finishes at the negative rail. 26 PFL Mix & Output Module Diagram XL88_3 The channel module pfl lines are individually selected by the eight push buttons with associated Led indicators that are located on this pcb B2702. The pushes keep the select lines high +15V in the off state and
8、at 0V in the selected (on) state. The select lines are fed to the modules via the ribbon cable buss connected to ST1. The pfl audio mix buss enters the module via ST1 pin 10. It is buffered by IC1a and the signal fed to IC2 the balancing network for the Pfl output which appears on three terminal pin
9、s ?H? hot ?C? cold and ?G? gnd,the output is protected from excess voltage by the diode bridge D9-12, and set for maximum common mode rejection at 100Hz by VR1 typically 85dB. The three terminal pins are connected by screened cable to the rear panel mounted XLR PFL Output socket pins 1 G, 2 C and 3
10、H. The facility to link together the pfl mix buss of more than one XL88 mixer exists on the pfl board. Two terminal pins are fitted 0V and Sig. These give direct pfl buss input. If this is to be used, the 3 pin Pfl output xlr should be replaced with a 5 pin xlr, the pfl output should be connected to
11、 pins 1, 2 and 3 as above and the pfl buss input should be connect to pins 4 0V and 5 SIG. Switch LED powering. The status LEDs are powered by the current source based around Q1. The order for the chain is from Q1 to the pfl select switches 1 thro? 8 and then to the negative rail. Module power conne
12、ction. The mixer power supply connects to ST2 on this module. From here it is distrib- uted to all other modules by the main ribbon cable. 40 pin headers are used for the channel modules with a 20 pin header on the pfl module. The first eight ways are used for this purpose as follows:- PIN 1 & 2 - I
13、nput/output gnd. PIN 3 & 4 - Psu 0 Volts. PIN 5 & 6 - Psu -15 Volts. PIN 7 & 8 - Psu +15 Volts. 27 Earth lift. The input and output sockets have pin 1 (Gnd) common. This is not connected to the psu 0V as the latter is linked to mains earth. The XL88 is normally used with another console and the audi
14、o ground is established there. If however it is desired to use the XL88 as a stand alone unit, the grounds may be connected internally by fitting a link in the ?0V LINK? location by the side of ST1 on the Pfl mix & output module. A high value resistor may be found in this location to facilitate test
15、ing. This should be removed. 28 Power Supply The power supply provides the two power rails required for the successful opera- tion of the XL88 matrix mixer. PLEASE NOTE THAT THE POWER SUPPLY CONTAINS CIRCUITRY WHICH GENERATES LETHAL VOLTAGES. ALL SERVICING OF THESE UNITS MUST BE REFERRED ONLY TO AUT
16、HORISED SERV- ICE AGENTS OF KLARK TEKNIK plc. ON NO ACCOUNT MUST SERV- ICE WORK BE ATTEMPTED BY ANYONE ELSE. IF IT IS, THE WAR- RANTY WHICH COVERS THE EQUIPMENT BECOMES INVALID, AND KLARK TEKNIK plc ACCEPT NO LIABILITY FOR CONSEQUENT DAMAGE TO THE CONSOLE OR ANCILLARY EQUIPMENT. Voltage Changeover.
17、It is most important that power is not applied to the unit when changeover pro- cedures are incomplete, and that the power is disconnected by unplugging the mains lead before work is commenced. 1. Change the fuse. The fuse holder is located on the back of the unit above the mains input plug. The cor
18、rect fuse ratings are as follows:- 220/240 volt operation: 1A.(T) 100/110 volt operation: 1A.(T) The fuse is 20mm, HBC type. 2. 120/240 Changeover. The voltage change over switch is located at the rear of the chassis and its setting is clearly marked. The voltage label plate must be unscrewed to all
19、ow the setting to be changed. Ensure it is replaced after adjustment. 3. 110/220 Changeover This is carried out as above for the 120/240 changeover. It will require that the appropriate mains transformer has been fitted. This is ascertainable by the fact that the voltage selector cover plate is prin
20、ted 110 & 220. If this is not the case, please contact your nearest Klark-Teknik representative to arrange for the transformer to be changed. 29 Power Supply Assembly. Diagram XL88_PSU This contains the Mains transformer, fuses, voltage selection, rectifiers and linear regulators. Both negative and
21、positive sections of the supply are identical with there own full wave rectifier, smoothing capacitor and 1.5A fixed voltage regula- tor. The regulators are mounted off the board on a common heatsink and connected to the pcb by short jumper leads. The output from the psu is linked to the Pfl, mix an
22、d output board by a jumper lead and plug. 30 31 Warranty This product is manufactured by Midas and warranted to be free from defects in components and factory workmanship under normal use and service for a period of one year from the date of purchase. During the warranty period, Midas will undertake
23、 to repair or at its option, replace this product at no charge to its owner when failing to perform as specified, provided the unit is returned shipping pre-paid, to the factory or authorised service facility.* No other warranty is expressed or implied. This warranty shall not be applicable and be v
24、oid when this product is subjected to: a) Repair work or alteration by persons other than those authorised by Midas in such a manner as to injure, in the sole judgement of Midas, the performance, stability, reliability or safety of this product. b) Misuse, negligence, accident, act of God, war or ci
25、vil insurrection. c) Connection, installation, adjustment or use otherwise than in accordance with the instructions provided by Midas. * See enclosed service request form. Midas reserves the right to alter specifications without notice. This warranty does not affect the statutory rights of the UK cu
26、stomer. 32 COPYMASTER DO NOT REMOVE NOTE! This sheet is your Copymaster. Please duplicate on photocopier when needed. Service Request Form Please complete this form and send it to Klark-Teknik before returning the unit. Attach duplicate to the returned unit. NAME.TELEPHONE. AD- DRESS. . MODEL No.SER
27、IAL No. PURCHASED FROM.DATE. Please tick appropriate box REPLACEMENT PACKAGING REQUIRED YES NO 1) Describe symptoms of malfunction. 2) Which channel(s) exhibit(s) the problem? 3) Under what conditions does the problem occur? a) All the time b) After a while c) At high signal levels d) At high temper
28、atures e) Other (please explain) Is the fault: Permanent Intermittent 4) What did you do to isolate the problem to this unit? 5) Further comments. 33 Important Note It is often useful to call your dealer or the factory explaining the nature of the problem with the unit. In many instances the problem
29、 can be solved without returning the unit to the factory. If the unit has to be returned to the factory, use the original packing only. If you do not have the original packing, we will provide a replacement. Factory authorised service facilities are located throughout the world. Call your dealer or the factory for the location of the service facility nearest you. EVI Pro Audio Group Klark Teknik Building Walter Nash Road Kidderminster Worcestershire DY11 7HJ Tel: (01562) 741515 Fax: (01562) 745371
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