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Denon UD-M50

Discussion in 'Electronic Repair' started by ibbotsnm, Jan 26, 2005.

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  1. ibbotsnm

    ibbotsnm Guest


    Hi Richard

    I have obtained the repair manual from a company here in the UK an
    have recently tried to re-align the trays.
    Firstly the manual although helpful in listing the various parts etc.i
    loses a lot in the translation from Japanese to English. I think yo
    are absolutely correct in your assumption that the trays are arranged
    It is probably necessary to fully dismantle the CD assembly from th
    rest of the unit first before any realistic repairs can be carried out
    I have a copy of those instructions if you require one. My proble
    was that the initial snarl up was because of one of the two sprin
    mechanisms that elevate the disc in the drive position had itsel
    miss-aligned due to a small part of the plastic breaking. This
    repaired and after quite some time I managed to understand th
    'Carousel' action of the mechanism. By rotating the small bevel gea
    (the white one that drops loose when the unit is disasembled)
    complete turns the first tray (Tray 2) is made to traverse from th
    rear to the front of the unit. Place tray 1 into the rear of the uni
    and turn the gear a further 5 turns and it should travel from the rea
    to the front as did the first tray, at the same time the first tray i
    elevated up to the top front position. the tray will need a littl
    assistance during this operation since it normally works the other wa
    up and relies on gravity to lift (drop) the tray into position.
    similar operation is followed by tray 3 so allowing tray 2 to take ove
    the drive position. I also found that the gears didn't rotate fully fiv
    times the second time but jammed causing the whole mechanism to foul up
    I managed to cure this by disassembling the whole gear mechanism an
    turning the 'black gears' to a slightly different position from where
    was then able to rotate the whole mechanism freely. Although i
    appeared to work when operated by hand, once I had reassembled th
    whole unit it refused to operate fully under power. Thats where
    stand at the moment. No longer jamming but not yet fully aligned.
    will crack the problem yet.!!!

    Let me know how you do. I will copy the written procedure if yo
    require it.


    regards Norman Ibbotso
     
  2. simona2001

    simona2001 Guest

    Hi Norman and Richard

    I'm particularly interested in whether either of you have found
    solution in terms of alignment with the CD trays of the M50 unit.

    I'm in the same boat in that the mechanism is out of sync after 2 CD
    were accidently placed in the same tray.

    When reassembling the trays I'm guessing right that in the front of th
    mech tray 1 is placed above tray 2 and tray 3 resides in the lowere
    reading position?

    Does the service manual show or describe how the cogs and trays ar
    positioned for assembly, if you still have a copy of the manual I woul
    be very grateful if you could email me a copy.

    Many thanks!

    Simo
     
  3. Arfa Daily

    Arfa Daily Guest

    I have a set of alignment diagrams for this deck. It's dead easy once you
    know how. It's actually a Sanyo manufactured mech. Before reassembling, ie
    putting any trays into the drawer, rotate the whole side gear assembly (
    both sides will turn because of the coupling rod across the drawer ) several
    turns in both directions, and make sure that this action is completely
    smooth. It is quite common for one of the planet gears inside one of the
    large gears, to break. This then results in the gears sticking part the way
    round.

    If you look down on the two ' windows ' on either side of the drawer
    topside, you will see the tops of the four gears. If you then rotate the
    gears, you will see a line come around. These lines MUST be EXACTLY aligned
    side to side ( done by disconnecting the coupling rod, repositioning one
    side as required, then reconnecting the rod ), and also front to back on
    each side, so all four lines MUST be exactly on top at the same time. This
    is the starting point. The drawer is then turned upside down, and tray 2 is
    dropped in at the back with the first tooth located over the lower ' catcher
    pip ' on the large gear. This position is important. It's also important to
    check those teeth on the tray VERY carefully for damage.

    Now turn the little bevel gear ( assuming that you haven't lost it !! ) to
    the right, gently. The tray will start to be drawn in. Keep your left hand
    under it as you wind it in. When it gets to the front, and the lifting
    action starts, help it with your left hand fingers pressing up from below.
    When it has gone all the way up, stop. Now position tray 1 the same as you
    did for tray 2, and wind it in the same way. When it reaches the end, tray 2
    should start to retreat, if you keep winding. Rocking back and forth around
    this point will give you a good ' feel ' for whether you've got it right.

    Now push the white pin on the left underside, towards the front to lift the
    disc clamp. Put tray 3 in the back, and let the clamp back down again.

    Now slide the gear down the rod on the right side, until it's about half way
    down. Now, with the bevel gear in place on the drawer, offer the right side
    of the drawer into its groove in the chassis, such that the bevel gear
    meshes with the shaft gear, and the claw on the drawer locates over the
    shaft. Hinge the drawer down until the left side is resting on top of its
    groove. Now, using something very flat like a scalpel blade, push in the
    flat white plastic lever which is in the way of the left side going down. If
    you're pressing down gently on the left side as you do this, you'll feel
    when it gets out of the way. Now withdraw the scalpel, and press down
    firmly. The drawer will snap into place with an alarming " crack " ( but
    don't be alarmed ... ) And that's it really. It should just work first time.
    This mech is also fitted in a Philips model and a Grundig and of course a
    Sanyo. I've also seen it, with a different deck fitted, in a DVD player, but
    I can't remember what make.

    If you need the actual diagrams, mail me direct, and I'll pdf them for you.

    Hope this helps

    Geoff
     
  4. simona2001

    simona2001 Guest

    Thanks for replying Geoff.

    I have followed your instructions but when I reassemble the loadin
    mech and power on and select a tray to open, tray 1 slides back and
    can hear the motors trying to turn but the mechanism jams and eject
    tray 2, I've never seen the mechanism raise tray 3.

    If you could send me a copy of the diagrams I would be very grateful,
    can't see a way of mailing you direct on these forums?

    Simon
     
  5. davie_snert

    davie_snert Guest

    Hi Norman

    I have the Denon UD M50. Not having the cd changer problem, but a
    having a laser problem - it skips for no apparent reason. Have trie
    various CDs, cleaned them all thoroughly, but it still happens. Jus
    wondered if the repair manual would help. Do you have a link where
    could get a copy of the repair manual? Thanks!!

    Dave Marshal
     
  6. kayal

    kayal Guest

    Guys
    i have just repaired my first Denon m50 ,(thanks to norman ibbotson fo
    emailing me his worksheets)
    if you listen you can blasting away in the back ground.
    my first attempt failed miserably. 2nd time i was away, where i score
    was, before i inserted the first tray after aligned the dots, i chec
    the back end for the marking on the gears (all four)
    1st error a swift a disengaging the cross shaft and manually moving th
    gears to the correct alignment and reinserting the cross shaft carefu
    to keep the gear markings right. i then proceed to insert the trays
    the manual only says about two, the general advise previous to this wa
    set tray 3 the rear play position. i carried on turning the gear afte
    inserting tray 3 , tray 2 comes back and tray 1 lifts and tray 3 goe
    forward.
    reassembled as per manual.
    when assembled, if you then look on the top you can see the smal
    driving wheel i then proceed to turn this wheel (i think it wa
    clockwise, if the tray moves to the play position then its right) an
    watch the mechanism work i keep going though a full cycle to ensure th
    was no jam. i carried on to tray one is in its position ie ready t
    eject. final check the markings on the gears are correctly aligned
    reassembly.
    great the tray work perfect, but the cd won't read the disc's
    disassemble check movement of lens, great reassmble, still the same,
    removed the tray clamp assembly so you can see the laser lens. get
    good clean brush (i used a camera lens brush) and gave the lens and th
    surrounding sensors a good going over, result one happy bunny.

    so dave i would suggest you manually cleans the lens, but do not touc
    the lens with your fingers or use solvents, it can leave grease smears
    a clean stiff clean brush is best
     
  7. tomh

    tomh Guest

    Yes keep your fingers and solvents off but do not use a "stiff brush".
    The lens mounting is very sensitive and flexible. It would be easy to
    damage the linkages that support it if too much force is used. At the
    shop where I worked we used a Q Tip, medical grade-wood handle, and with
    clean fingers pulled the cotton tip part way off the stick. This gave a
    soft but still firm without being hard end. Gently scrub/wipe the lens
    in a circular motion. When it's clean you can see a really nice
    reflection across the surface of the lens. You might also try blowing
    the lens assy with a dusting can, again gently. This will knock out or
    dislodge any "big dust bunnies" that might be in the linkage area. Most
    PS2's that boot but won't read disks can be fixed with a good lens and
    drive sled cleaning. Good luck
     
  8. webtronix

    webtronix

    2
    0
    Mar 31, 2007
    denon udm50

    hi there , i have just inherited a ( once tried and meddled with ) unit - it seems some kids been messing with it and the trays were pushed , hence misaligned - . i have followed half way through your advice on alignment of the main cog wheels ( 4x ) which control the trays , but not so sure on installingin the trays in the deck - do i need to remove the top half of the carriage away from the base ( 6 small screws ) - or have i to remove the full carriage away from the laser unit ? , ( its been a long while since i worked in my workshop ( brings back some memories !!))
    any futher help will be graetly appreciated ,
    so far i have removed all the trays from the deck - alligned the cogs correctly - reinstlled in the unit and the cogs whirl away happlily - try to eject and it only ejects 2 inches and stops ( has the tray misaligned too? ) the cd flap ( aluminium ) alos rises / desends but not happily , i bet u can tell i have never worked on a 3 disc changer unit - ( help ) -
    or can i bring it round one weekend for u to fix ??? :)

    ash -
     
  9. webtronix

    webtronix

    2
    0
    Mar 31, 2007
    denon ud m50

    hi there , i have just inherited a ( once tried and meddled with ) unit - it seems some kids been messing with it and the trays were pushed , hence misaligned - . i have followed half way through your advice on alignment of the main cog wheels ( 4x ) which control the trays , but not so sure on installingin the trays in the deck - do i need to remove the top half of the carriage away from the base ( 6 small screws ) - or have i to remove the full carriage away from the laser unit ? , ( its been a long while since i worked in my workshop ( brings back some memories !!))
    any futher help will be graetly appreciated ,
    so far i have removed all the trays from the deck - alligned the cogs correctly - reinstlled in the unit and the cogs whirl away happlily - try to eject and it only ejects 2 inches and stops ( has the tray misaligned too? ) the cd flap ( aluminium ) alos rises / desends but not happily , i bet u can tell i have never worked on a 3 disc changer unit - ( help ) -
    or can i bring it round one weekend for u to fix ???

    ash -
     
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