Say what you will about Hi-MD, but it's another niche within a niche for those that seek the best possible quality from their MiniDiscs.
Read more about it on the many websites and wikis out there, but just know that you need a dedicated Hi-MD recording device and Hi-MD players since they used a different format than normal recordable MiniDiscs.
Yes, you can reformat a "normal" MiniDisc into the Hi-MD format and fit some uncompressed music on there, but Hi-MD also featured 1 Gb discs that were nearly triple the capacity of "normal" MDs.
Please read more about this format that really was "too little, too late" as flash memory players and iPods came along.
Either way, we're not here to discuss the practicality of MiniDiscs nor Hi-MD!
We've chosen this format and these devices because we love the nostalgia and tactility of this format.
Sony made a few portable Hi-MD devices like the simple MZ-EH50 and this nicer MZ-EH70. The MZ-EH70 was more premium with a metal build (versus the MZ-EH50's plastic body), nice on-body controls, and the "HD Digital Amp" with a lower noise floor.
As easy as it is to work on the MZ-EH50, the MZ-EH70 is one of the more difficult devices to get into since it's not exactly obvious how to take it apart nor reassemble it easily.
I've taken the time to "play" with a pink MZ-EH70 that was having intermittent "read errors" and I've taken photos and a video below.
As far as I can tell, there's no service manual available, so I hope this helps any MZ-EH70 owners out there!
I'll provide a walkthrough here, but please check out YouTube if you want to see me take it apart and put it back together!
The first thing to note about getting into the MZ-EH70 is the apparent lack of ways to get in after removing the lower case screws. The top lid's screws are partially obscured by the plastic trim and the bottom doesn't just slide off like most MD devices.
OK so if you want to supplement the YouTube video with some pics and steps, let's go!
- First, remove the bottom case screws - 4 total
- Remove the battery door by prying gently and sliding it off
- GENTLY - pry from the back of the trim (battery door side) on each side directly outwards to pop out the tab that's holding it in on each side. Check out the pictures below that show the inside view of how the tabs are inserted (circled).
- Note - if you're careful, you can remove the entire mechanism from the bottom case without popping off/loosening the side trim
- The arrows you see are the "hooks" that keep the plastic trim tightly on the metal frame. Once you unclip the circled tabs, you can lift upwards to loosen the "hooks".
- Again, you must be gentle or you will twist and break the thin plastic trim near the front. It's all connected!
- Once the rear tabs on each side are loosened, gently pull upwards on the sides of the plastic trim until they are just barely loose and hanging freely from the sides. If you pull outwards too hard or twist too far upwards, you will break them off of the thin plastic trim by the headphone jack!
- We needed to pull them out slightly on each side because they are keeping the main mechanism in the lower casing. Now, we can pull from the back/battery side and lift the entire mechanism upwards and outwards away from the headphone jack and charging connectors. Watch the video to see it in action.
- Once the mechanism is out, you can now fully access all 4 lid screws and clean/lube the sled rail and gearshaft.
- Now, getting it back together can be a bit of a pain, but take it slowly...
- Get the lower case and trim in place (hanging loosely on each side - not clipped in) like it was when we removed the mechanism.
- I prefer to hold the bottom casing so gravity pulls the Eject slider and Hold switch downwards (orient it so the charging contacts would be upwards) and double-check that your hold switch is set correctly on the board.
- Now, we slide the mechanism in favoring the charging contacts side, then the headphone jack. I know, it sounds weird so you may need to see the video.
- So - empty metal bottom case, place trim in position leaving it loose on the left/right sides
- Slide the main mechanism in place, charging contacts first, then headphone jack
- Ensure the mechanism's metal "lip" is over the plastic trim along the front edge
- Slowly slide it all forward (note, there's tape along the rear edge to allow this!) and it should slot in.
- Lock the trim into place with a slight downward motion (to "hook" in the proper tabs) then push the rear-most parts of the trim straight into the metal casing. It should fit tightly with no gaps
- Secure the bottom case screws
- Replace the battery door
I've added some pics below for reference - please see the videos for more details!