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Posts posted by imkidd57

  1. OK well finally back with a report of success with the Drive B encoder. Did the connection reversal for pins A and B of the encoder (1 and 3 on the PCB diagram from the service manual). No need to cut the tracks as both solder ring pads had been lost but I still had to undo the track repair. Also, in the process of de-soldering the encoder for the nth time, the solder pad for pin 4 also came off, so had to make a new bridge connection for that.


    Another figure of the rather messy repair: hairs on the area were from cotton buds during cleanup. Pink stuff is nail varnish remaining from the earlier track repair.




    Anyway after covering the area with Kapton tape and reassembling the rewired PCB back into the front panel, all functions of the encoder were exactly as anticipated (clockwise + counter clockwise) and the push-button switch works fine. Earlier worries about the amount of force needed to push the switch were allayed and it is not so forceful as to move the whole deck.


    With the above success I revisited the left-sided encoder (Drive A) of the W1 and rewired it according to the principle above, which is a much more solid repair as all the legs can be soldered to the board and the bridge wires added. It's a different wiring layout, which I can include in a repair section of the MD Wiki as requested.


    Thanks everyone, especially of course @kgallen for all the advice.

    • Thanks 1
  2. Well repairing drive B side turned into a flipping nightmare! The solder ring pads surrounding the holes for A and B of the encoder became detached - probably too much messing about with the soldering iron, sucker, flux, desoldering ribbon, and IPA. Then the A and B legs fell off the second encoder after trying to carefully bend them out of the way to reverse the connections. Track repair with fine wire was successful but was then very hard to connect the wires to the stumps of A and B; and now the encoder itself may be knackered 🤣. To highlight the nightmare, I ordered some more encoders from Farnell but all I received today was a bag of hexagonal nuts 🤪. I do wonder at their warehouse QC...


    On review this whole affair may be better solved by reversing the A & B connections at the end of the circuit board where the tracks from the pins lead to a ribbon connector that joins with the central display board, rather than messing about with the fragile pins of the encoder. The PCB appears to be one-sided; so now that the ring pads for A and B have gone, and the tracks have become non-continuous, after looking at the diagrams in the service manual I am proposing to take jumper wires from each A & B leg and solder to the reverse points on the pads of the distant ribbon connector (pins 8 & 9). It's not very far (~2 cm) and should be far easier to manipulate than bending the encoder legs again.


    Any thoughts?


    Here is the schematic from the SM:






    ... and PCB mask with actual positions:



  3. 21 minutes ago, kgallen said:

    Thanks for the update and info. That is weird. I wonder if Sony had a custom part made for some reason. I’ve suspected that before - the headphone volume control on one of my MDS-E10 or E12 didn’t seem to be a standard part. That mounts to the PCB to the side so the flat on the shaft needs to be at a different position to get the knob marker to line up between the min and max position. Also I couldn’t find the correct resistance (I can’t remember now if it was 1k or 5k).


    Not at all - thanks so much for all your help 😀! I'll add some more pictures during drive B modification, and hopefully will be a useful resource in case a fully compatible encoder can't be found.


    I noticed that the same Sony part number for the encoder is listed for the MDS-JE520 and JB930.

  4. As a practical update, with your advice kgallen I reversed the connections A and B of PEC11L onto the PCB with some thin insulated wire, and the encoder rotation is now as it should be: turning clockwise increases the track number count, and also progession through the menus. Push switch still works as expected and the whole left-hand side PCB fits back onto the main front panel.


    Because of the lack of support by the two pins now not soldered onto the board, as a precaution, I added a collar to the threaded bit of the shaft so it would fit exactly in the hole of the main front panel (you can see that the Sony original part is a lot thicker (9mm) and a snug fit in the hole). This should help counteract any inadvertent sideways stress on the remaining PCB connections during rotation of the AMS knob.

  5. Thanks very much for all the info, kgallen!


    Second time around I chose the PEC11L as it was a low-profile version, and couldn't see a PEC12 equivalent and I never thought there would be a difference in rotation. All the PEC12Rs had a base which was too thick (~6mm); even the PEC11R I got first time. It's true though that both PEC11s are threaded. Here the three encoders to show the difference:



    Encoder comparison.jpg

  6. Yes it's weird! I've looked through the PEC11L datasheet but to my untrained eyes I can't see anything about variants with different rotation directions. I have attached it in case there is something I missed.


    It may come down to something I've done in the soldering; e.g. accidentally bridged to another pin or something! I will go back and check under magnification.




  7. Thanks - well there has been some good progress. The low profile encoder fits great and allows the PCB to be replaced properly in the front panel, without any stress on it or the other switches. Also, the plastic AMS knob fits better on the shaft and no filing is needed to get it on (or off).


    Reconnected the ribbons and wires, powered on the deck and it works! Rotating the dial moves through tracks on MDs, and the push-on switch plays the track. In the menu the rotation similarly moves back and forth through the options, and the push-on selects the one arrowed. However, going forward through the numbered tracks on an MD, or going through the menu options is via an anticlockwise rotation, whereas it should be clockwise (checked on a working MDS-W1 deck).


    I don't know enough electronics to understand if this can be corrected, say by swapping the pins of the A and B contacts where they are soldered to the board (see 'quadrature output table' in previous post, lower left hand diagram, where I presume CW and CCW are the rotation actions). Would anyone be able to suggest a way of reversing the current action?

    • Like 1
  8. Update...


    Well it turns out that the thickness of the encoder base is quite important, as the recess in the front panel had exactly 4.8mm depth for the original to fit. When mounted on the PCB, the newer Bournes unit thickness of 6.6mm won't allow the PCB to lie flat where it belongs on the front panel, and fixing it with the screws would mean the PCB would bow out and put at risk the PCB traces, amongst other hazards! Also the push switches present on other parts of the PCB won't engage properly with the corresponding buttons on the front panel.


    I thought of filing some of the front panel plastic structure away to accomodate the thicker encoder base, but that puts at risk the separate springy bits of plastic which connect the surrounding three panel buttons and provide the back-spring support to them when pressed.


    Further searching around what is available in the UK reveals a low profile version of the Bournes encoder (model no prefix PEC11L) with a 4.5mm base, and there is a 20 PPR / 20 detente; 20mm shaft; momentary push switch.


    Overall the code is: PEC11L-4120F-S0020. Farnells have it in stock so I will order a couple of those which should probably fit better.









  9. I can report that the Bournes RE unit is mostly physically compatible; the five (2 + 3) electrical pins are exactly right for distance and perfectly fit the holes in the panel control board. The two larger support lugs/clips were slightly too wide to fit in their rectangular holes in the board, but it was easy to file a bit off each side of the lug; I'd say about 0.5 - 1mm in total). Then it was a good snug fit onto the board and easy to solder everything on.


    Very slight potential problems I can see are:

    • the base of the replacement RE unit is thicker than the Sony original, so the shaft may protrude further out in the recess of the W1 front control/display panel. However it is only 1-2mm at most, and there may be some leeway in the AMS knob recess that can accomodate that. Otherwise the shaft length could be reduced with a bit of coarse filing.
    • The diameter of the shaft is very slightly larger than the original, so it is a very tight fit for the AMS knob. I was reluctant to push it on fully as the plastic forming the D-socket of the AMS knob is thin and likely to be brittle. Even though there is a metal grip ring, I would rather try and reduce it with some sandpapering - it wont require much reduction though.
    • The pressure needed to actuate the momentary push-on switch is more than the original. I am hoping that it's not enough to move the whole deck when being used - the WI is quite a light deck! Somewhere in the specification sheets it was possible to choose a different pressure for the push-on function, but I can't remember whether it was for the Bournes units.

    Positive aspects are that the rotary clicks feel just like the original, and shaft is aluminium; consequently will be much more robust than the plastic of the original that was prone to snapping.


    I've not had time to replace the board and test electrically but will do over the weekend.


    New rotary encoder soldered in place:


    New RE in place.jpg



    Encoder unit size comparison: original Sony part is the black one.


    RE comparison.jpg

  10. I am repairing an MDS-W1 deck, which has quite a few problems including both AMS knobs which will not work properly; there is no spring to the 'push' action and no response from the W1 deck itself to any push/pull movement. One of the knobs won't show a change on the display to rotating it, but you can feel the clicks. Thanks to minidisc.org there is a service manual, and I took off the front panel of the W1 and located the left side panel board with the AMS unit on. The potentiometer-like unit is described in the manual as a 'rotary encoder', and was relatively easy to desolder the pins and lugs and remove it from the board.


    With the expected lack of a direct Sony spare part, I managed to disassemble the encoder to investigate and found it irrepairable, with some of the internal parts reduced to fragments which explains why it wasn't working! Looking on Farnell's website, I think I've found a possible replacement in terms of the various physical measurements, the right pin positions and is a push-on switch, but being completely new to rotary encoders I would like some advice on the electronic digital aspects of pulses per rotation (PPR) and detente (number of clicks felt when turning the spindle).


    When disassembled, the original unit had a disc with radial copper stripes, of which there were 20. Can I assume that these were responsible for the pulses, as very small copper pickups - one of which was still in place in the wreckage - would have contacted the stripes and could have generated the pulses. If so, then would this be a 20 PPR rotary encoder? The number of clicks felt on another working MDS-W1 deck that I have is definitely 20 for a whole rotation, so this is should be the detente.


    The possible replacement from Farnell is 24 PPR (and detente of 24), so would this make any difference to the performance and suitability? I can't see that an extra four clicks would screw things up as it doesn't seem to be doing anything other than change an observable number or menu option on the display.


    Any advice and opinions gratefully received!




    Rotary encoder.jpg

  11. Asivery also mentioned recently that they have got working the upload (PC -> MD) of the .aea files that have been downloaded (MD -> PC) from SP recordings. IIRC that was the only thing missing from the application; apparently soon to be released in a new version.

  12. Another bump to this very useful topic...


    I had no idea that the R5ST had internal batteries, and this thread was a great alert to investigate!


    My internal batteries had also leaked and corroded the terminals a bit, but it seemed to be all dry and crusted without obvious spread to circuit boards and components. Was reluctant to use water, which could spread it further but scraping with fine screwdriver, finer cleaning with fibreglass brush whilst holding the unit upside down, seemed to do the trick.


    As for replacement batteries, I had a few old NiCad and NiMH size AA 1.2V which I had previously revived by charge/discharge. However they were mostly a bit too big in width or length to fit back in the unit; luckily there were 2 NiMH slightly smaller than the rest, which went in without too much force. Let's see what happens... I don't know how to ensure that any replacements ordered on-line would be the exact right size.


    BTW the power supply is supposed to be 9V 1.2A, not 6V. My R5ST came with an original charger which gives the spec (see picture).


    Also, before the recent event of swapping out the internal batteries, the unit went dead even with the original charger, and I thought it was toast. However I noticed the <reset> button on the underside of the case, and with the mains power connected, held it down for about 15s. Then the unit magically came back to life and was no trouble since then. No idea why it worked, but may be worth a try if anyone has a unit that seemingly fails.




  13. As a point of accuracy, most legacy recorders will apply a time-stamp to an MD recording, which will be written to sector 2 in the TOC information. With some decks, this information is accessible via the 'Retry Cause Display Mode'.

    The minidisc.org archives are a valuable source for this [1, 2]. It' a slightly precarious procedure as you have to pretend to record on a disc, then put the machine into a form of service mode which allows the time-stamp to be displayed for each track by rotating the AMS knob. The process can be exited without actually recording on the minidisc's TOC.

    *Edit* - Actually after trying out on a JB920, it seems this info can be retrieved from the disc without the process of intending to record. Insert disc into the deck, then when the TOC information appears, press the <stop> button for 10-15 seconds and the display changes. Rotate the AMS knob to get time-stamp info for each track in the format YYMMDD. The examples below show tracks on MDs recorded on:

    • 2003-04-17 (17th April 2003)
    • 2006-09-03 (3rd Sept 2006)
    • Small extra track recorded today (5th Jan 2021)


    Unfortunately for the OP, I don't think this is possible for portables; it's not mentioned in the service manual for the MZ-N505.

    Finally, of course the time-stamp will only be accurate if the original recorder had its clock set correctly.


    1. How to put the deck  unit into 'Super-Undo mode' (Retry Cause Display Mode) -> http://www.minidisc.org/super_undo.html

    2. How to display the info (e.g. on an MDS-JE520); second table, top panel -> http://minidisc.org/retry_cause_display_mode.html


    MD time pic 1.jpg

    MD time pic 2.jpg

    MD time pic 3.jpg

  14. Thanks NGY - that is a great suggestion. In practice, the critical tolerance for fitting into the MD compartment is the thickness of the LiPo component (the 'front-to-back depth' of the one on your image). It's definitely worth a try though... could you provide a link to the eb@y seller's items?

  15. OK so I made two ;-)

    Was pretty straightforward from the instructions given on the original site. It's a very well-designed shell for the parts, and my earlier doubts about the battery being loose in the frame were unfounded as I didn't read properly: it is held in place with glue between its 'wings' and the frame.

    A few minor comments:

    1. The areas on a new print that catch inside the MZ-NH1 casing are the '+' and '-' characters, which were printed raised a bit too high. Easily reduced with careful sandpapering.
    2. The new LiPo battery's original orange sellotape, that covers the small charge regulator PCB,  presents a raised hard edge to the MD battery slot as you slide it in. To fix this I carefully removed the orange stuff and replaced it with Scotch Magic tape, the edges of which were tucked below the height of the main battery and sealed with superglue. A better solution may be to embed the PCB in UV-setting epoxy, but this works well for now and the battery is protected inside the MD case.
    3. I charged the new assembly outside the MZ-NH1, just in case something had gone wrong with the circuitry, but it proceeded fine. Currently got two MD units soak-testing with continuous play, but 2 SP MDs into the test there is still full charge indicated on the displays.

    Now all that's needed is a case to hold a few of these...


    • Like 1
  16. How did you get on, Rusty?

    I printed a shell on a Prusa i3 MK3s+ in PLA, and although a bit rough and ready, it fits inside an MZ-NH1 quite well. A couple of areas needed a touch of sandpaper to stop them catching.

    Will try soldering the contacts and attaching a LiPo battery in the next couple of days.



  17. FYI... I noticed a post by someone who created a 3D-printed shell for the new LiPo battery type, thus disposing of the need for the original LIP-4WM case with its extra thickness. The shell is printed on an Ultimaker, which is a fairly top-end machine, but some members may have access or could verify the print accuracy on a different unit (the .stl file can be downloaded from that page). It could also be useful to verify whether the new arrangement is a frictionless fit in Sony portables other than the RH1 which use the LIP-4WM, such as the NH1.


    The only slight drawback I can see is that the new battery is loose within its new shell, and would fall out unless supported when removed. So would need a case to carry around any spares.

  18. OK can you be a bit more specific with your trials; it sounds like you have the outer covers off, but let's not assume.

    • Did you use a charged and verified AA battery, or a 3V power supply?
    • Pressed <Play> button with either blank or recorded disc?
    • Does anything appear on the display, with or without a disc?
    • Which electrical tap points are you measuring at, and what voltages are you expecting to see?
  19. Another confirmed plus for this method; and one suggested slight modification. There seems to be a couple of layers of the orange tape holding the replacement battery's regulation circuit in place, which increases the thickness of the whole assembly. It's possible to take the outermost piece of sticky orange tape off, and 'unroll' the circuit away from the battery itself, reducing the thickness for eventual easier insertion into the MD player. There's still one layer of orange tape remaining to protect the little circuit board.

    I set the half-assembled new battery to charge in an external charger, which initially metered it at 57%, then rapidly got to the 90% mark and added around 107 mAh in 41 min before declaring it 100% full. Added the new battery assembly to an MD-NH1, and it signalled on the MD's display also as full. Then added the NH1 to the original charging station (with original Sony power supply); the charging light came on and MD displayed it as full with '00' min charging, and switched off as expected.

    I'll discharge it fully in the player and see what happens... but it looks good even with both protection circuits in place.

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