How to modify the
Sony MZ-R700/R500/G750/N707/N505/N710's
EEPROM settings to add advanced features

MZ-R700 TO MZ-R900

Peter Maksymiuk, Poland
Documentation and Testing: Eric Woudenberg
November, 2002
Updated 7/2003 with [email protected]'s additions for MZ-N505/707 series machines
Updated 8/2003 with Globox's additions for MZ-N710 series machines



Sony apparently uses some common DSP and system firmware in their Minidisc recorders but selectively disables certain functions on low-end equipment. The instructions below show how to change two EEPROM values to enable features that are normally available only on more expensive MD equipment.

The table below shows the features available with Factory Default ("D") settings and with the Upgrade Hack ("H") for various units.

Feature v / Recorder -> R900 N1 R700 R500 N707 N505 G750 N10 N910 N710
Fancy play modes: All, All Repeat, 1 Track, 1 Track Repeat, Shuffle, Shuffle Repeat, Program, Program Repeat D D H H H H H D*6 D*6 D*6
Personal Disk Memory (remembers volume, program play, equalizer, and speed settings for 20 discs) D D H H H H H D D H
M-Timer (an alarm clock settable in minutes -- so you don't miss your train stop) D D H H H H*1 H D D H
Auto time mark (inserts a track mark at regular intervals during recording) D D H H H H H D D D
Selectable stored equalizer settings (sound 1, sound 2) D D H H H H H D D D
Titling in Japanese Katakana character set (as well as the normal Roman alphabet)     H H H H H      
Selectable LINE/HEADPHONE output from audio jack D D *3 *3 H H *3 D D *3
Selectable microphone sensitivity D D *4 *4 *4 *4 *4 D D D
Digital Pitch Control (-80% to +110%) D D H*2   H*2 H*2 H*2 D D H
Tone control settings beyond simple bass boost D D H*2   H*2 H*2 H*2 D D D
Key: "D": Factory Default, "H": Upgrade Hack

  1. On the MZ-N505 the display does not show the timer's 1's digit, so the value shown is approx. times 10.
  2. These functions are only available with the addition of an MZ-R900 remote (RM-MC11EL), its unbacklit brother (RM-MC10L), or the MZ-N1 remote (RM-MC12ELK)(see appendix for remote signalling information)
  3. Unit's integral headphone amplifier lacks headphone/line selection circuit found in upscale model (see e.g. diagrams of the MZ-R700 and MZ-R900 audio circuitry).
  4. Unit's integral microphone amplifier lacks sensitivity selection circuit found in upscale model (see e.g. diagrams of the MZ-R700 and MZ-R900 audio circuitry).
  5. The Date/Time stamp function requires a battery backed time-of-day clock that is only present on the high-end models.
  6. Also features Bookmark and Bookmark Repeat modes


Warning: These modifications require that you enter service mode on your unit. It is easy to render your machine inoperative in this mode. We make no guarantees that this will not happen to you! Proceed at your own risk. If your machine does not display the values indicated, exit service mode by removing power -- this procedure may not be suitable for your machine.

This procedure discusses the MZ-R700 but the steps are nearly the same for the other machines. The only difference between the them is in the value of settings 1 and 2, and entering Service Mode on the MZ-N710, as noted in the text.

These modifications are made from the keyboard, proceed as follows:


Turn off the hold switch, apply power, put an MD in your machine and start playback. Press ENTER, use FF to scroll through the display. You should see new modes such as M-TIMER and PERSONAL.


You have successfully upgraded your machine without wrecking it. Now have a look at the MZ-R900 user manual or MZ-N910 user manual to figure out how to use the new features.

Changing it back

If you need to restore the machine to to its factory settings, repeat the modification procedure given above, but replace the first and second settings values with whatever values you wrote down when you changed it originally.


Appendix A: Sony MZ-R900 Remote Control resistance values

Sony remote controls place various electrical resistances across pins 2 and 4 of the remote plug to signal button presses to the main unit. We give here the resistor values for the MZ-R900 remote.

The remote plug appears thus (from the Mironics DIY titler page):

|<<1000 ohms
Sound2300 ohms
>>|3640 ohms
Pause5160 ohms
Stop7100 ohms
Vol – 8400 ohms
Vol + 9900 ohms
Rpt/Ent (aka Track Mark)11900 ohms
Display16700 ohms

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