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SA 070931

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Sennheiser electronic GmbH & Co. KG • 30900 Wedemark
Phone: +49 (5130) 600 0 • Fax: +49 (5130) 600 300

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DRM 85

DRM 85-C

Service manual

Short description

The Digital Recording Microphone is based on traditional microphone 
techniques in order to achieve excellent acquisition performance. It includes 
embedded recorder functionalities, that stores the digitized audio data 
to a 1 GByte NAND Flash Memory.

The USB port can be used to download the audio data to a PC with a standard 
browser as well to upload configuration data from PC to the DRM. Two AA 
mignon alkaline batteries provide about 7 hours continous power.

Features

Omni-directional condenser capsule at DRM 85,
cardioid condenser capsule at DRM 85C

Pre-record buffer 0 to 10 seconds

Digital / Analog converter

DC/DC converter

Summary of Contents for DRM 85

Page 1: ...ormance It includes embedded recorder functionalities that stores the digitized audio data to a 1 GByte NAND Flash Memory The USB port can be used to download the audio data to a PC with a standard br...

Page 2: ...afety and certification reasons it is forbidden to alter the product without authorization Otherwise the person who has altered the product is liable for any consequential damage repairs exchanges The...

Page 3: ...agram 32 AF board printed circuit board component side 33 AF board printed circuit board solder side 33 Connector board circuit diagram 34 Connector board printed circuit board solder side 35 Connecto...

Page 4: ...itch control USB connector 5 pin Mini B PHONES monitor output 3 5 mm 3 pole jack socket Record mode LED REC LED 6 character alphanumeric display Display backlight 16 segment bargraph meter provides an...

Page 5: ...___________1 mono Microphone capsule ___________________ DRM 85 ________________________omni directional DRM 85C _______________________cardioid Record level _________________________automatic gain co...

Page 6: ...e ________________ 3 VDC Operating voltage ____________________ 2 VDC to 3 VDC Current consumption at nominal voltage _______________ approx 175 mA Battery ____________________________ 2 x mignon AA p...

Page 7: ...ntains the user interfaces like headphone output jack USB jack and the LC display It links all control and data signals to and from the codec on the AF Board to the processor on the CPU Board The CPU...

Page 8: ...ection The code memory can be programmed with the operating system software using the Background Debug Mode BDM development tools from Windriver via the BDM port J500 The code memory is also protected...

Page 9: ...RM target hardware 3 3 3 Real time clock Real Time Clock U203 type Ricoh R2051 K provides the CPU with a source of time and date information upon request via an IIC connection The time and date inform...

Page 10: ...played on the LCD 3 3 5 AF signal processing The AF Board hosts the microphone preamplifier section an audio codec and a headphone amplifier Audio signal voltages from an electret microphone capsule a...

Page 11: ...Capsule modules The module for DRM 85 accommodates an electret capsule of 9 8 mm with a bearing ring and a special designed snapped in filter plate assembled with silk in front of the modul to be opt...

Page 12: ...DRM 85 C DRM 85 12 41 09 2007 30 40 50 60 dBrA Hz...

Page 13: ...DRM 85 C DRM 85 09 2007 13 41 10 20 30 40 50 dBV Hz...

Page 14: ...o remove the capsule on its own without dismantling the end cap or the removing the AF board first remove the protective basket 001 by unscrewing counter clockwise when viewed from the top of the micr...

Page 15: ...scratch the case or damage the rubber keypad If a screwdriver is used this is very easy to do Figure 3 Keypad The rubber keypad is lifted away and then thekeypad PCB 018 can be carefully removed Care...

Page 16: ...sure the PCB s slide out of the end cap squarely 3 4 6 Separate chassis and barrel First remove the protective basket fig 2 001 Ensure that the coloured ring is not misplaced when the basket is remove...

Page 17: ...ow in fig 8 can be seen Figure 8 Location of AF PCB To remove the AF PCB the flat ribbon cable fig 10 012 has disconnected from the AF PCB This is done by lifting the black locking latch on the connec...

Page 18: ...ed the AF board may be removed on its own by sliding down and out of the front end of the chassis 3 4 8 Connector PCB removal After removing the AF PCB the connector PCB 009 can be removed Remove scre...

Page 19: ...st be removed and the three connections from the battery compartment must be unsoldered very carefully Once the screw 014 is removed the connections can be unsoldered 3 connections as shown in fig 12...

Page 20: ...he black latch holding the ribbon cable 012 from the Connector PCB 009 to the LCD module 010 Exercise extreme caution and do not use sharp tools to remove the LCD ribbon cable it is very delicate Figu...

Page 21: ...require particular care and these are detailed below 3 5 1 LCD lens replacement The LCD easily clips back into place but ensure the inside surface is cleaned before assembly of the end cap onto the un...

Page 22: ...5 6 Capsule replacement The capsule replacement is straightforward but make sure that the connector pins opposite the screw socket on the capsule are in correct alignment with the socket in the unit t...

Page 23: ...that is mounted on the Connector PCB 009 This connector is located at the bottom left hand corner of the PCB in Figure 2 9 1 indicated by arrow Guides in the end cap moulding precisely locate the PCB...

Page 24: ...on The display will show DRM85 and go no further Move the rocker switch up or down If the display shows SAME them remove the batteries and start again but move the rocker switch in the opposite direct...

Page 25: ...ector between the Connector PCB 009 and the Keyboard PCB 010 one half of the mating pair will have detached from the Connector PCB at the solder pads Figure 19 Keypad connector Repair requires disasse...

Page 26: ...5 26 41 09 2007 4 Exploded view 002 001 003 005 007 008 009 018 020 013 017 017 019 014 021 015 016 017 010 011 012 006 001 002 003 004 Modulst ckliste Batteriefach Part s own module parts list Batter...

Page 27: ...lap for battery compartment 002 pad flap battery compartment 003 holder 006 PCB holder metal 007 PCB AF 008 PCB CPU 009 PCB connector 010 LCD 011 flat cable 30xRM0 5 012 flat cable 15xRM0 5 013 lens s...

Page 28: ...audio analyzer 1 Frequency counter e g Rohde Schwarz FSP 7 1 RF power meter e g Rohde Schwarz FSP 7 or Rohde Schwarz NRVS 1 Multimeter e g FLUKE 177 1 Laboratory power supply unit 0 to 30 VDC 1 A e g...

Page 29: ...sequence stops see also the LOW BAT logfile entry in the DRM 85 root directory 2 2 current consumption when in operation see 2 1 see 2 1 ampere meter in series to the power supply typ 175 mA 2 3 DC DC...

Page 30: ...e file transfer see 2 1 1 for hearing your own noise during recording insert an 32 headphone in the DRM 85 jack socket 2 press the DRM 85 REC button 3 speak into the microphone your own noise is audib...

Page 31: ...DRM 85 C DRM 85 08 2007 31 41 6 Circuit diagrams Block diagram...

Page 32: ...P114 TP115 TP116 TP117 TP118 TP119 TP120 TP121 TP122 TP123 10nK C179 10nK C180 33u6V3 C181 4 7nK C182 4 7nK C183 4 7nK C184 220RJ R194 1 2KJ R195 470RJ R196 BAT54 SW D101 1 2 3 BAT54 SW D102 1 2 3 WCK...

Page 33: ...29 R125 R121 R109 R103 R101 Q101 L105 L103 L101 D102 D101 C193 C192 C190 C189 C188 C187 C184 C183 C182 C181 C180 C179 C177 C169 C168 C159 C153 C139 C118 C117 C113 C111 C105 C103 C101 C145 C149 C166 TP...

Page 34: ...S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23 S24 S25 S26 S27 S28 S29 S30 S31 VDD CS IRQ HT1621B U205 41 42 43 44 45 46 47 48 1 2 3 4 5 6 7 9 8 10 11 12 13 14 15 16 17 18...

Page 35: ...C239 C241 C247 C249 C250 C251 C252 D 2 0 3 D210 IF1 J205 J212 J213 L201 L203 L 2 0 5 L206 L207 R200 R202 R204 R206 R223 R228 TP201 TP202 TP203 TP204 TP205 TP206 TP207 TP208 TP209 1 1 2 P T 0 1 2 P T T...

Page 36: ...41 08 2007 S1 S2 S3 TYCO M4 P1 1 2 3 4 RECORD STOP PLAY MENU 512682 B 2 S 1 S S3 L 1 IF1 P1 Keyboard PCB circuit diagram Keyboard PCB printed circuit board component side Keyboard PCB printed circuit...

Page 37: ...VSS E3 VSS A1 30FLZ RSM1 TB J400 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 HPA_PDN K9W8G08U1M U401 CLE 16 ALE 17 CE1 9 CE2 10 RE 8 WE 18 WP 19 R B1 7 R B2 6 PRE...

Page 38: ...IA MCF5249 U500 D16 P8 D17 N7 D18 P7 D19 N6 D20 P6 D21 P5 D22 L7 D23 K7 D24 F2 D25 G1 D26 G2 D27 H1 D28 H2 D29 J1 D30 J2 D31 K1 A1 B6 A2 A5 A3 B5 A4 A4 A5 B4 A6 A3 A7 B3 A8 A2 A9 C1 A10 C2 A11 B1 A12...

Page 39: ...3 ISP1582 U602 VCCio 21 34 48 VCC 53 54 VCC_1V8 28 1 4 0 5 29 26 DGND 13 5 AGND 1 59 60 61 62 DIE_PAD 63 64 65 66 67 ISP1582 U602 CS 15 RD 16 WR 17 A0 18 A1 19 A2 20 A3 22 A4 23 A5 24 A6 25 A7 27 XTAL...

Page 40: ...0 TP507 C500 C501 C502 C503 C504 C505 C506 C507 C508 C509 C510 C518 C520 R400 R500 R501 R502 R503 R504 R505 R507 R509 R515 R516 R518 R519 R520 R521 R522 R523 R524 R528 R531 R532 R533 R534 R535 R536 R5...

Page 41: ...U403 U600 U603 C511 C512 C515 C613 C614 C616 C617 C619 D504 D505 D608 R540 R553 R554 R555 R603 R 6 2 3 TP432 TP434 TP436 TP438 TP440 TP441 TP442 TP445 TP446 TP447 TP448 TP449 TP451 TP452 U501 U503 U6...

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