AustralianMonitor-DCM500-pwr-sm维修电路原理图.pdf

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1、 DCM500 Service Manual Product Description Set-Up/Test Procedures Component Lists Full Schematics PCB Overlays RadioFans.CN 收音机爱 好者资料库 DCM Series Circuit Description The DCM series are power amplifiers designed for commercial installations. They can be used for either low impedance (4 ohm/8 ohm) or

2、constant voltage line speakers (100v/70v). These amplifiers can be mounted in a standard 19” equipment rack or they can be used on a shelf or table. The DCM series feature line level input (with parallel output) and are normally used with mixers, mixer amplifiers or other power amplifiers. The DCM s

3、eries will operate from mains voltage or 24VDC. The DCM series also feature a DC battery trickle charge facility, auto-sensing fan cooling, plus overload, short circuit and over temperature protection. Power Switch This switch controls the switching of AC power to the amplifier. A blue On LED will i

4、ndicate whether the amplifier is switched on or off. This switch will not switch DC power on or off in DC operation. In DC operation mode, the amplifier is always on and the blue power LED will always be illuminated. If both AC and DC voltage supply are connected and the AC power switch is in the of

5、f position, the amplifier will continue to operate normally from the DC supply and the mains fail LED will indicate. Level Control The output level control is located in the centre of the front panel. It is a fully recessed screwdriver adjustable pot. Turning this pot cw will increase the gain of th

6、e amplifier. At maximum setting the input sensitivity is 300mV. The amplifier ships from the factory with the sensitivity set to 1V. Amplifier Status Display This VU meter indicates the output level of the amplifier. The sensing for the circuit is taken on the amplifier side of the output transforme

7、r. The 0dB level is referenced to 100V. This is an RMS meter, not a peak meter. Protect The protect LED will illuminate when the amplifier cuts out because of either over current or high temperature. The amplifier will switch back on after approx 4 sec for an over current trip. The amplifier will sw

8、itch back on after the amplifier has cooled to 60degC for a thermal trip. Limiter The limiter is a hard limiter with an attack time of about 1msec. It is defeatable by removing the jumper on the solder side of the front pcb. This however is not recommended as voltage overload and speaker transformer

9、 current saturation may cause the amplifier to cut out under normal program material. Current Limit and Setup Current limit is controlled by a microprocessor (PIC12C509A). The detection is done by sensing voltage across the emitter resistors. Trimpot P1 on the front pcb is accessible through the hol

10、e in the top right of the chassis return (only visible with the lid off). Turning the trimpot ccw will decrease the point at which the amp cuts out ie the amp will cut out earlier. (P1 resistance is increased.) To set the current limit: 1. Reset the trimpot P1 turning fully clockwise. 2. Connect the

11、 amplifier to half its minimum load (10ohm for DCM500, 20ohm for DCM250, 40ohm for DCM120). 3. Run an rms 1kHz sine wave into the amplifier and set the input level so that you read 425mVDC (DCM250/500) or 825mVDC (DCM120) across the emitter resistor, measuring the side which has the higher current (

12、measured as a voltage across the emitter resistors). 4. Turn the trimpot P1 ccw till the amplifier cuts out. The amplifier is set to the factory default. Thermal and Fan control and Setup RadioFans.CN 收音机爱 好者资料库 The thermal cutout and fan is controlled by a microprocessor (PIC12C509A). The temperatu

13、re is sensed using a 10k25degC NTC. The fan is normally off and turns on to full speed at 60degC. This temperature is fixed and not adjustable. The thermal cutout temperature is set using the trimpot accessible through the hole in the top left side of the chassis return (only visible with the lid of

14、f). Turning the trimpot cw will decrease the point at which the amp cuts out ie the amp will cut out earlier. Power Amp The power amplifier is a push pull single supply amplifier driven by a class A transformer coupled front end. The drive is provided by HEXFETs (RF9520/9530) into NPN BJTs (TIP35C).

15、 When replacing the FETs it is recommended that you replace both FETs. The matching of these FETs determines the balancing of the emitter currents in the output devices. For optimum performance the emitter currents in each side should match to within 30% of each other. Bias Setup The amplifier is se

16、t with a bais setting of 1mV measured across the emitter resitors. Bias is set using the trimpots located on the power pcbs on each side of the amplifier. Turning the trimpots cw increases the bias. If the HEXFETs have been replaced the resistor in series with the pot may need to be changed. Use a l

17、ower value resistor if the bias cannot be turned off or a higher value if the bias cannot be turn on. AC Power Inlet The operating voltage is 230/240 VAC 50 Hz. The 3 pin IEC power inlet is located on the bottom left of the rear panel and accepts a standard mains power lead fitted with an IEC connec

18、tor. Before plugging in a power lead, please check the rear panel of the amplifier to ensure that the voltage switch is set correctly for your part of the world. The inlet is equipped with an in-built AC fuse containing the rated fuse and a spare. 24 Volt DC Power Inlet The DCM series feature option

19、al 24VDC power to run off a battery back-up if required. This is connected via the rear binding posts. The front panel Power Switch will not switch DC power on or off in DC operation. In this mode the amplifier is always on. The trickle charge resistor across the diode is a 47ohm/5watt wire wound re

20、sistor. The maximum trickle current is 300mA supplied from internal 35V rails. 230V/240V Slide Switch The operating voltage of the amplifier is user selectable between 230V and 240V via a slide switch located on the center of the rear panel. This switch should be set to match the AC voltage of your

21、country. The mains transformer is wound with a 230V winding plus a 10V winding internally connected. Speaker Output Terminal Strip The screw terminals located on the top left of the rear panel allow access to the direct speaker outputs of the amplifier. Reading from left to right the terminals are:

22、COM Common or “-” for low impedance speaker loads (4 or 8 ohms) 4 Positive “+” for 4 ohm speaker loads (use with common) 8 Positive “+” for 8 ohm speaker loads (use with common) DCM120 only COM Common or “-” for 70v or100v speaker loads 70 Positive “+” for 70v line speaker loads (use with common) DC

23、M120/500 only 100 Positive “+” for 100v line speaker loads (use with common) Please ensure that the correct “Common” is used. Low impedance and 70/100v loads can be used simultaneously but please pay careful attention to the overall speaker load. Note: The minimum impedance (or maximum load) at 100

24、volt line should be no less than DCM120 80 ohms DCM250 40 ohms DCM500 20 ohms XLR Audio Input and Parallel Output The DCM series includes both male and female 3 pin XLR connectors per channel. While the female is normally used as the input to the amplifier, both XLRs are connected in parallel so eit

25、her will work. The XLRs inputs are transformer balanced and wired as: Pin 1: Shield. Pin 2: Hot, +, Positive Pin 3: Cold, -, Negative Fuse Sizes (DCM120) Mains: 230 VAC 4 Amperes Slow Blow HRC 20 x5mm DC: 10 Amperes Slow Blow HRC 20 x5mm (DCM250) Mains: 230 VAC 6.3 Amperes Slow Blow 20 x5mm DC: 2 x

26、10 Amperes Slow Blow HRC 3AG (DCM500) Mains: 230 VAC 10 Amperes Slow Blow HRC 20 x5mm DC: 2 x 35 Amperes Slow Blow 3AG TESTING PROCEDURE OF DCM 120/DCM 250/DCM 500 I. PRE-TESTING (of complete sets). Check 1.1 All screw for tightness (Bridge rectifier and transistor bolts) 1.2 Earth Connection for go

27、od contact (solder and crimpling) 1.3 This setup has signal input to the Amplifier through male (XLR) 1.4 Check with Multimeter that there is a DC resistance of about 250 between Pin2 & Pin3 of each of XLRs. Also between (Pin 1 & Pin 3) and (Pin1 & Pin2). There should be very high resistance. (IE: n

28、o reading). 2. Electrical Check 2.1 Fuse Check: DCM 120 DCM 250 DCM 500 Mains fuse: 4AT 6.3 AT 10 AT DC fuse: 10AT (x1) 10AT (x2) 35AT (x2) 2.2 Connect the Amplifier to the setup (Variac voltage = 0V) set all presets on front board (only) fully clockwise, voltage selector switch to 230V 2.3 Slowly i

29、ncrease the input voltage to 230V, keep watching the input current should not exceed 0.1A for DCM-120, 0.1A for DCM-250, 0.1A for DCM 500. 2.4 Check and reset if necessary all emitter resistor voltages with the help of preset. (Each emitter resistor voltage should be between 0.5 mV to 0.8 mV ) 2.5 C

30、heck DC voltage Main rail = 33V 7815 input = 30V 7815 output = 15.5V 2.6 Give input signal of 500 mV to get outputs as follows ( 4 output load)/ 22V for DCM 120, 32VAC for DCM250, 44.7VAC for DCM 500. Check 100V O/p at 100vV line, Remove the input signal II. FINAL TESTING (This setup should have sig

31、nal input to Amplifier through female (XLR) (The limiter link should be out of circuit initially.) 1. Connect the Amplifier to the setup, set voltage selector switch to 240V 2. Switch ON the set to 240VAC. 3. Slowly increase the input signal (of 1kHz) keep watching the 24dB LED, it should glow at ap

32、prox 9V output. Increase the input signal to get 70VAC output. 4. Check Dc voltage of all emitter resistors, Minimum value should be within 30% of the maximum value. 5. Slowly increase the input signal, keep watching the 0db LED, it should glow at 100V 5V output voltage. 6. Set 100V 1kHz as 0db refe

33、rence. Change frequency to 10kHz check dB level drop. It should be 2.5dB 0.5dB. 7. Change the frequency to 1kHz, reduce signal level to get 10VAC output. Half the output load. 8. Overload setting: - Check the DC voltage at the emitter resistors having the maximum voltage value. Increase input signal

34、 to get 820mV for DCM 120, 425mV (for DCM250 & DCM 500). Turn preset (P2) anticlockwise such that it just mutes the output signal and signal returns back slowly after 2 seconds. 9. Reduce the signal & re check whether the signal mutes at the corresponding above stated voltages. 10. Again make the ou

35、tput load to original full value. Turn volume preset fully anticlockwise, set input signal strength to 1V, set volume preset clockwise to get 100V output. 11. Set input signal strength to get output 110V VAC. Insert limiter link, the signal should reduce to 100V 5V. 12. Remove the input signal and c

36、heck noise. It should measure less than 25mV. III. THERMAL & SOAK TEST 1. Connect the Amplifier to the setup : Output load = 4 Output Voltage: (DCM 120): 14V. (DCM 250):20V. (DCM 500): 40V 2. Set the Amplifier thermal cut off temperature at around 105C with the help of preset P4. 3. Leave the unit “

37、ON” (with lid fixed, if possible) for 24 hours. IV. Sound Test/Listening test. 1. Switch On the set. Check for any switch on thump. 2. Connect CD player to the input, listen for irregularities if any. 3. Switch off the set check for switch off noises. 12345678 A B C D 87654321 D C B A Title NumberRe

38、visionSize A3 Date:6-May-2003 Sheet of File:C:DCM ManualsCD6203-1.DDBDrawn By: C8 0.15u S1 F3 35A F1 10A F2 35A D1 40A C3C4C2C1 BR1 T1 R2 47R R1 4K7 R3 100R D3 12V D2 RY1 BR3 C5 4u7 C6 4u7 C7 10u V1 BC639 C 5 4 3 2 1 X1 1 SBG - + 24V BATTERY +35VDC 240AC IN 10000U X1X4X2X3X5X6 X7 123 X8 123 CD6203-1

39、 DCM500 POWER SUPPLY PCB6203 2 12345678 A B C D 87654321 D C B A Title NumberRevisionSize A3 Date:8-May-2003 Sheet of File:C:DCM ManualsCD6201-12.DDBDrawn By: R42B 10R R39B 4K7 R37 0R D4 V16 R39A 10R R40 0R R38B 47k R38A 47k D2A D2B R1B 220R R1A 220R D3B D3A R11B 4K7 R11A 4K7 V3B BC556 V3A BC556 T2

40、IC1A 78L05 C1B 820P R36B 500R D1B R6B 150R R15B R22 R14B 2K2 R13B R22 R12B 2K2 R15A R22 R14A 2K2 R13A R22 R12A 2K2 C1A 820P R6A 150R D1A R36A 500R V2B V2A V5B V5A V4B V4A V1B V1A R7B 10R R7A 10R R8B 470R R8A 470R R9B 1K R9A 1K R5B 150R R5A 150R R4B 1K R4A 1K R3B 220R R3A 220R R2B 220R R2A 220R R10A

41、1K R10B 1K IC1B 78L05 V7AV8A R18A 2K2 R19A R22 R20A 2K2 R21A R22 V7B V8B R18B 2K2 R19B R22 R20B 2K2 R21B R22 V6A V6B R17B R22 R17A R22 R16A 2K2 R16B 2K2 V9A V9B R23A R22 R23B R22 R22A 2K2 R22B 2K2 R40B 1K R41A 10k NTC R41 NOT USED C X4 TO FAN X3 TO PCB6200 X2 X2 TO PCB6200 X1 X1 TP PCB6203 PCB6202 X

42、4 TO FAN X3 TO PCB6200 X4 X2 TO PCB6200 X3 X1 TO PCB6136 PCB6201 R34 =2K2 R24,R26,R28,R30,R32, R35 = 0.22R R25,R27,R29,R31,R33, V10-V15 = TIP35C DCM500 PCB6202 PCB6201 CD6201-1 DCM500 POWER PCB FAN 2 1 X4 5 5 4 3 X3 2 1 X3 5 4 3 2 1 X1 5 4 3 2 1 X2 FAN 2 1 X43 4 X3 TIP41C 24V6 5 35V2 1 X3 3 2 1 X1 5

43、 4 3 1 X2 2 +35V +35V SBG 1 100VAC COM 11 X TIP35C 11 X TIP35C 70AC 4 OHM 2 12345678 A B C D 87654321 D C B A Title NumberRevisionSize A3 Date:6-May-2003 Sheet of File:C:Protel FilesCDTRAXCD6200-14.DDBDrawn By: VDD P4 10K VDD R51 1K R42 1K D27 D13 VCC V6 BC546 R55 10K R56 10K IC2B LM358 VCCVCC AGND

44、AGND AGND VDD R31 10k R30 10K VCC R29 10K V5 BC546 C11 22u VDD IC5 7805VCC VCC VDD R36 10K R13 10K V7 BC546 C33 4u7 R53 1K C5 2u2 P2 47K R12 100R C3 10u R11 390R R10 1K R9 5K6 D2 D1 R272M2R16 2M2 R17 47K R14 22R C18 4u7 C16 100u C15 100u R34 22K R33 22K D4 C8 100P C23 100P C6 2u2 C19 47u V3 BC546 1

45、2 3 5 6 7 8 4 9 10 11 12 14 15 16 13 IC3A SA571 C17 2u2 C14 47PC13 47P R28 100K R15 100K C12 2u2 C10 2u2 R25 10K R24 10k R23 10K R22 10k R21 39k R20 10k R19 100K R18 1K IC4B LM833-B IC4A LM833-A C4 2u2 C7 100u IC1 7815 P1 2K C2 2u2 C1 2u2 V2 BC639 V1 BC639 T1B T1A R8 100R R7 100R R6 680R R5 680R R4

46、10K R3 10K R2 68K R1 68K IC2A LM358 R35 33K LK2 LK3 0R C9 .47u C26 4u7 LK4 0R VDD 1 GP5 2 GP4 3 GP3 4 GP2 5 GP1 6 GP0 7 VSS 8 IC6 PIC12C509 D26 D24 D23 D22 D21 D20 D19 D18 D17 R48 1K R49 10K LK6 0R R46 1K2 R45 2K7 D25 R41 D31 C35 4u7 VCC R43 470R R44 1K C32 4u7 V4 BC556 D10 D16 V8 BC556 R26 10K VCC

47、V9 BC556 R32 470K C20 47u PROTECT Desc 2. 3. 4. 5. 6. 7. Pin GP5-IN = THRML SENS GP4-IN = FAN SENSE GP3-IN = I LIMIT GP2-OUT = PRTCT/MUTE GP1-OUT = FAN CON I/O PowerCurrent Limit Fan ControlThermal SenseProtect/On Indicator Battery IndicatorVU Display Mute/Limiter/DriveMicroprocessor X4/1 X2/6 (N/C)

48、 IC6/P2 IC6/P3 X4/3X2/4 FAN CONTROL POWER X2/5 X4/4 IC6/P5 IC6/P6 AGND IC6/P7 IC6/P4 IC6/P5 (N/C) D X4/2 X4/6 X3/1 X3/3 X3/5 X3/2 X3/4 X1/3 X2/2 X2/1 X1/2 X1/1 X4/5 GND 8V2 SBG 1 16VDC X5 1 DCM DRIVER CD6200-1 X2/3 LN3915 -21 -15 -9 -6 -3 0 +3DB10 11 12 13 14 16 18 1 42 8 7 6 5 93 17 15-12 -18 -25 I

49、C7 X1/4 X1/5 MAINS FAIL * * R41=15K=DCM120/500 R41=12K=DCM 250 GP0-OUT = 1/2VCC CON DCM500 Power Supply Components List Designato Part TypeDescriptionManufacturers code BR1KBPC3504Bridge recitfier 600V/35A2134800356 BR3KBPC3504Bridge recitfier 600V/35A2134800356 C115000uFElectrolytic Capacitor 50V2121250153 C215000uFElectrolytic Capacitor 50V2121250153 C315000uFElectrolytic Capacitor 50V2121250153 C415000uFElectrolytic Capacitor 50