Sennheiser DRM 85 Service Manual
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Sennheiser DRM 85 Service Manual

Sennheiser DRM 85 Service Manual

Digital recording microphone
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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
Service manual
Sennheiser electronic GmbH & Co. KG • 30900 Wedemark
Phone: +49 (5130) 600 0 • Fax: +49 (5130) 600 300
DRM 85
DRM 85-C
SA 070931
1/41

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Summary of Contents for Sennheiser DRM 85

  • Page 1 DRM 85C • Pre-record buffer 0 to 10 seconds • Digital / Analog converter • DC/DC converter Sennheiser electronic GmbH & Co. KG • 30900 Wedemark 1/41 Phone: +49 (5130) 600 0 • Fax: +49 (5130) 600 300...
  • Page 2 Otherwise, the person who has altered the product is liable for any consequential damage. repairs/exchanges The following instructions for overhaul and testing must be followed. In case of unusual problems please contact your Sennheiser distributor. CAUTION During SMD component soldering you may destroy them by using a standard soldering iron for several seconds.

  • Page 3: Table Of Contents

    Processor board, circuit diagram, part 1/3..............37 Processor board, circuit diagram, part 2/3..............38 Processor board, circuit diagram, part 3/3..............39 Processor board, printed circuit board, component side ......... 40 Processor board, printed circuit board, solder side........... 41 DRM 85-C, DRM 85 09/2007 3/41...

  • Page 4: Controls And Indicators

    Display backlight 16-segment bargraph meter - provides an indication of recording and playback level “PLAY“ - indicates FlashMic is in replay mode “REC“ - indicates FlashMic is in record mode 4-segment battery status indicator DRM 85-C, DRM 85 4/41 09/2007...

  • Page 5: Specifications

    1 minute to allow battery change. set / synchronized by host computer application according to host computer clock. manual setting on DRM 85 by menu item. File format __________________________broadcast wave file (.wav). linear PCM or MPEG 1 layer 2 compressed.
  • Page 6 “Mini B”, 5 pin User presets ________________________ Up to 9 presets in a preset.cfg file, uploaded from host computer, selected by menu item on DRM 85 Pre-record __________________________ off/ on, up to 10 sec in 1 sec step, configured with FlashMic Manager...

  • Page 7: Description

    The KE10 capsule is optimized to an omnidirectional characteristic specially for DRM 85 as well as KE14 to a cardioid characteristic for DRM 85-C. The signal of the capsule is preamplified, digitized and linked via the connector board to the coldfire processor on the CPU Board.
  • Page 8 Rec. LED and also the Batt. Symbol on LCD flashes. A next threshold downwards triggers a shutdown of the device. Exact values for all thresholds are defined in the software documentation. DRM 85 has about 7 hours life time, measured with VARTA blue batteries and also with Panasonic Accu 2000 mAh.
  • Page 9 NAND flash memory and USB protocol software, the DRM appears to the remote PC as a removable disk drive.The connected state allows operation direct from USB power with no batteries fitted. DRM 85-C, DRM 85 09/2007 9/41...
  • Page 10 In record mode the Line input at the codec is controlled active for leveling by the AGC as well as for the recording and the monitoring path. The recorded level is –6 dBFs defined as the best compromise between clipping and S/N. DRM 85-C, DRM 85 10/41 09/2007...
  • Page 11 For DRM 85 C it is an electret capsule of 14.5 mm ∅ with the same filter plate but different silk on it optimised to a cardioid characteristics. It is easy to distinguish the cardioid capsule as it has two extensions on either side of the front plate of the capsule.
  • Page 12 DRM 85-C, DRM 85 12/41 09/2007...
  • Page 13 DRM 85-C, DRM 85 09/2007 13/41...

  • Page 14: Disassembly

    [001] and allow access to the screw [004], which holds the capsule in place. Remove screw [004] then push the barrel back toward the end cap and the capsule can be gently pulled from the chassis [005]. Figure 2: Capsule removal DRM 85-C, DRM 85 14/41 09/2007...
  • Page 15 Care should be taken to keep the interboard connector (shown by arrow in fig 4) square when separating the keypad PCB from the connector PCB, otherwise the connector may be damaged. Interboard connector Figure 4: Keypad removal DRM 85-C, DRM 85 09/2007 15/41...
  • Page 16 (as the FlashMic is viewed with the capsule to the left), through the barrel. Figure 6 shows the chassis and PCBs, complete with capsule, with the barrel and end-cap [fig. 2, 004] removed. Capsule screw 004 Figure 6: FlashMic Chassis & PCBs DRM 85-C, DRM 85 16/41 09/2007...
  • Page 17 Once the cable is free the screw [fig. 7,013] T06 Torx is unscrewed. Now remove the screw holding the capsule in place [fig. 7], if it was not removed earlier in section „capsule removal only“. DRM 85-C, DRM 85 09/2007 17/41...
  • Page 18 [015] with a T06 Torx driver being careful to retain washer [016]. Figure 10: Connector PCB This will leave the connector board only linked via the flat ribbon cable [fig. 10, 012]. Turn the connector board over to gain access to the ribbon cable latches. DRM 85-C, DRM 85 18/41 09/2007...
  • Page 19 12) and the CPU PCB removed, this must be done with care to en- sure no damage occurs to the PCB or the battery connecting wires. Battery compartment solder connections Battery compartment solder connections Figure 12: CPU PCB solder connections DRM 85-C, DRM 85 09/2007 19/41...
  • Page 20 Then unclip the LCD [010] from the PCB [009] by moving the 4 LCD clips (shown arrowed in fig. 15) to release the module. LCD clips LCD clips LCD clips LCD clips Figure 15: LCD clips DRM 85-C, DRM 85 20/41 09/2007...

  • Page 21: Assembly

    Check that the CPU PCB holes for the soldered connections are clean before reassembly. Insert the CPU PCB in place checking the battery connections are in place in the PCB holes then screw the board in place using the T06 Torx screw before soldering the connections. DRM 85-C, DRM 85 09/2007 21/41...
  • Page 22 – check these are correctly aligned, and do not force the end cap into place. When replacing the three T08 Torx screws [017] do NOT over tighten as this could strip the threads in the battery chassis [005]. DRM 85-C, DRM 85 22/41 09/2007...
  • Page 23 PCB but it is essential to push the Keyboard PCB onto the socket squarely, otherwise damage to the plug or socket could result. location of keypad PCB connector Figure 18: Keypad PCB connector DRM 85-C, DRM 85 09/2007 23/41...

  • Page 24: Firmware Including Updates

    Units marked FMO, either on the box or on the microphone label, are pre-production prototypes. They are NOT suitable to be used be any of the released versions of firmware and should be returned to HHB! DRM 85-C, DRM 85 24/41 09/2007...

  • Page 25: Known Faults

    PCB, it is most important to ensure the socket is square to the PCB once soldering is complete. Connector resoldered Figure 21: Connector re-attached DRM 85-C, DRM 85 09/2007 25/41...

  • Page 26: Exploded View

    Exploded view (002) Modulstückliste: Batteriefach Part's own module parts list: Battery compartment DRM 85-C, DRM 85 26/41 09/2007...
  • Page 27 PCB AF PCB CPU PCB connector flat cable 30xRM0.5 flat cable 15xRM0.5 lens screw 2.5x4 screw 2x6-4.8 Torx lens screw M2x12 TORXT6 washer screw 2.5x8 Torx PCB keyboard rocker cover 34.5x21x2.2 LCD label silver DRM 85-C, DRM 85 09/2007 27/41...

  • Page 28: Test And Alignment Instructions

    , 1 A, e.g. HAMEG 8142 Note: Make sure that your measurement and test equipment is regularly calibrated. Measuring set-up AF input (speak into the microphone) DRM 85 DC input Laboratory power supply PC with FlashMic manager software Multimeter DRM 85-C, DRM 85 28/41 09/2007...

  • Page 29: Test Table

    1.1; and terminal strips terminal strips are locked current and voltage measurement – operating voltage supply +3 V DRM 85 = ON +2 V current battery contacts +3 V limitation min. 500 mA LOW BAT: REC LED is +1.8 V...
  • Page 30 2.1; transfer 1. for hearing your own noise during recording insert an 32 Ω headphone in the DRM 85 jack socket. 2. press the DRM 85 “REC“ button. 3. speak into the microphone (your own noise is audible via your connected headphone) 4.

  • Page 31: Circuit Diagrams

    Circuit diagrams DRM 85-C, DRM 85 08/2007 31/41...

  • Page 32: Af Board, Circuit Diagram

    DRM 85-C, DRM 85 32/41 08/2007...

  • Page 33: Af Board, Printed Circuit Board, Component Side

    C168 DRM 85-C, DRM 85 08/2007 33/41...

  • Page 34: Connector Board, Circuit Diagram

    DRM 85-C, DRM 85 34/41 08/2007...

  • Page 35: Connector Board, Printed Circuit Board, Solder Side

    DRM 85-C, DRM 85 08/2007 35/41...

  • Page 36: Keyboard Pcb, Circuit Diagram

    TYCO-M4 RECORD/STOP PLAY MENU Keyboard PCB, circuit diagram 512682 B Keyboard PCB, printed circuit board, component side Keyboard PCB, printed circuit board, solder side DRM 85-C, DRM 85 36/41 08/2007...

  • Page 37: Processor Board, Circuit Diagram, Part 1/3

    DRM 85-C, DRM 85 08/2007 37/41...

  • Page 38: Processor Board, Circuit Diagram, Part 2/3

    DRM 85-C, DRM 85 38/41 08/2007...

  • Page 39: Processor Board, Circuit Diagram, Part 3/3

    DRM 85-C, DRM 85 08/2007 39/41...

  • Page 40: Processor Board, Printed Circuit Board, Component Side

    C400 DRM 85-C, DRM 85 40/41 08/2007...

  • Page 41: Processor Board, Printed Circuit Board, Solder Side

    DRM 85-C, DRM 85 08/2007 41/41...

This manual is also suitable for:

Drm 85-c

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