YouTube - MiniDisc repair - Sony MZ-R900 Service Menu - getting in and out!

The Sony MZ-R900 is a great, high-quality Sony MiniDisc recorder with an aluminum body and dual "jog dial" controls on the left and right side. 

Personally, I like it a lot even though it's not a NetMD-capable device. It feels solid and substantial which I value more than thin and light when were just talking about a matter of millimeters.

I strongly encourage you to read this post first and have it handy while you're navigating the Service Menu. I've created a short video here:

Service Menu - what is it for?

The MZ-R900 (and other devices) had a service menu built into the device for situations when it needed to be serviced. For example, if something happened to the laser's calibration, you could take it to a service center and have them recalibrate it. Or maybe you were fixing something inside and nudged the write head or other part and want to be sure everything's still working fine (NEVER HAPPENNED TO ME).

The good news is the entire process is documented in the device's service manual, but the bad news is that it's about as clear as an upside-down road map. Seriously, I've read a ton of technical documentation from different manufacturers, software companies, appliance manufacturers, etc., and this is one of the most non-straightforward ones.

I think they tried their best to include some documentation and some illustrations/charts, but it still has a long way to go. Luckily, someone took the time (a long time ago) to document their struggle with it and after trying it, I'd like to update it since one of their techniques didn't work for me. More on that later.

Basically, once you're in this mode, you're going to want to use the "auto calibration" tests that are included so your device can calibrate the laser on normal media and CD/"pressed" MDs. There's also a power test that will require a power adapter. Once all tests are done and the parameters are set, we will exit the service menu and have a working device!

The plan is to get into service mode, run the tests you need, then exit. 

Optionally, the plan could be to erase/reset the EEPROM, then run all the tests, then exit. This step is more "dangerous" because if you can't clear all the tests (for example, if you don't have a CD/"pressed" MD, then you could be stuck in service mode even after a power off!

Before we get started, try to get the following ready:

  • Your device - Sony MZ-R900 or other models that have a similar service menu
  • Power supply - it's recommended (and required for one step) to have one available
  • A standard recordable MiniDisc (MD) that you don't mind erasing, ensure the write tab is set to allow writing to the disc
  • A "pressed" MD (you will see it referred to as a "CD" in the manual) - I understand these aren't that easy to come by, which does cause some people to get stuck in the Service Menu!

Getting started AKA the Konami code

OK not exactly, but it's pretty close! If you need to get into the service menu, turn on your device (I start with an MD inside) and do the following:

  • Turn on the Hold switch (rear on an MZ-R900)
  • Hold down the "Vol -" key
  • while holding "Vol -", use the right jog dial (player's display facing you) and flick it:
    • Right, Right
    • Left, Left
    • Right, Left
    • Right, Left
    • press Pause, Pause
  • Release "Vol -"

You should see the LCD flashing and display the version of firmware (VER) on the device. This is the "home" screen and we'll start navigating to the different menu items from here.

Manual mode and test selections

We're now going to enter "Manual mode" so we can pick just the tests that we want to run.

To do that, press the "Vol +" button (or Right by flicking the Right jog dial Up).

Once you do, the screen will display "Manual 000"

This just means you're now in manual mode and you're at function 000. We will go through a few different steps, run the tests then exit.

The functions are arranged in a hierarchy with [0-9]XX being a Master section, then X[0-9]X being a Lower section, and lastly XX[1-9] being a Function. This will make more sense later, but you don't even need to make sense of it if you follow along.

To navigate, you'll use the Right-most jog dial (player facing you) and flick the controller up/down and push Play to select sections. Sometimes you'll need to push Play to "enter" a section (10s, 20s, 30s, etc.) and then move up to 31, 32, 33, etc. Pause will select/run the test, and Stop will exit and put you back at Manual 000.

Make sure you have your MiniDiscs handy (one "CD" and one recordable that you don't mind erasing), and let's get started.

OPTIONAL - Resetting the EEPROM/NVCore

Only do this if you are sure of what you're doing. This will reset all values and require all tests to be passed before you can exit the service menu (even after cutting power!). There are methods documented to "escape" this mode, but they did not work for me. I had to pass the tests by acquiring a "CD" MiniDisc.

If you're convinced that you must do this and you have both a "CD" and MD, then:

  • press Play and flick the right jog dial up until you get to 021.
  • press Pause
  • the display will show "ResOK?" (Reset OK?)
  • tf you're sure of what you're doing, press Pause again
  • the display will show "Reset!"
  • Now the unit will be stuck in the Service Menu until you can complete all the tests below

Before starting these tests, I recommend using the proper power supply so you don't lose power mid-test. Some of these tests can take a few minutes to complete.

Test #1 - Playback of "CD" MD

  • go to menu option 031
  • insert your "CD" MD
  • press Pause and let the tests run
  • it should finish with "CD OK"

Test #2 - Playback of an MD

  • Go to menu option 032
  • Insert your "standard" MD that you're prepared to record over or lose
  • press Pause, and let the tests run
  • if successful, it should display "MO OK" (MO = Magneto-Optical; leave disc in for next test).
    • Note: if it doesn't complete successfully, you can try a different disc (happened to me once)

Test #3 - Recording on an MD

  • Go to menu option 033
  • press Pause, and let the tests run (it will record some silence somewhere)
  • if successful, it should display "ADJ OK"

Test #4 - Optional(?) Multiple Adjustments 

This was listed as optional on the original article I referenced, but I ran it to be safe:

  • Go to menu option 034
  • press Pause, and let the tests run
  • if successful, it should display "MO OK"

Test #5 Offset Adjustment

  • Go to menu option 035
  • press Pause
  • it should display "OfstOK"

Test  #6 Power Calibration

You must have a power supply connected to complete this test!

  • Go to menu option 036
  • press Pause
  • press Play to see the values for 762, 763, 764. I believe you can use "Vol -" and "Vol +" to edit them. 
The original article mentions trying to achieve the following:

762:11, 763:29, 764:25

I believe my values were close on one of my MZ-R900s, so I left them, but I did change them on another player that was "way off".

Test #7 - Finals and Exiting the Service Menu and returning to Normal mode

Now that all the tests are complete, we want to exit this mode with a final set of automated tests:

  • press Stop to get back to Manual 000
  • press Stop to go back to the main screen of the Service Menu (shows version # and flashes all icons)
  • insert a "CD"
  • use the Right jog dial to select Left (flick down)
  • display will show AssyXX (XX will be some characters like F1 or FF), 
  • press Enter (Left jog dial In)
  • push Left again and it will test your "CD" (Display will show "CD RUN", then "CD OK" if successful)
  • From here, you can put in your MD (MO, recordable) 
  • push Right (flick Right jog dial Up) to run the MO tests (Display will show "MO RUN", then "MO OK" if successful)

Lastly, with all tests run, you should be able to exit:

  • Go to menu option 024
  • you should see something like "024 Assy  XX->FF"
  • press Pause
  • remove power
  • restore power and you should be back to normal!

As mentioned earlier, the original article from 2002 mentioned that they could exit the Service Menu without using a "CD" by just going to menu option 024, but that NEVER worked for me. I had to find an affordable "CD" on Buyee and use it to finally complete all the tests.