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Hacking a Denon RCD M35DAB, CD of 2006, so far so good

Discussion in 'Electronic Repair' started by N_Cook, Aug 27, 2013.

  1. N_Cook

    N_Cook Guest

    Neither me or owner will spend out on a new optical unit (failed laser),
    big spondulics. But a near industry standard KSS 213C looked somewhat
    similar , so I tried it out. This one laying around , unknown condition,
    from some scrapped something. The ribbon feed lines for the 3 laser pins
    matched , the other 2 deck motor+switch leads matched up, so tried it
    out. Laser lit but logic of the end stops wrong so swapped the optical
    unit across to the original (scrapper would not have mechanically fitted
    in the Denon anyway). Required some bodging to fit, straightforward but
    too much for detailing here, but sledge etc worked .
    Adjusted power pot and cleaned lens and now consistently reads data
    track and plays about first 2 minutes track1 of any CD I try, faulters
    and stops, will not play any track 2 or higher.
    I suspect the registration of the centre limit switch is out, but could
    be a problem with the rack although powers up and down the slide without
    incident with only 2 volt on the motor, but I will try marking rack and
    cog of the 2minute stoppages. I assume a new (cheap) KSS 213 would show
    the same stoppage.
    So how to adjust the end stop , ? pieces of shim material added and
    subtracted in the gap between sledge and leaf switch and suck it and
    see? or some other problem likely?

  2. I think this is a sled motor issue; I have never seen any limit switch other
    than the inner (start) switch. As the tracking coil reaches it's physical
    limit, a player will skip or "falter and stop" just like you describe, if
    the sled does not advance.Check the voltage across the sled motor as this
    process unfolds. At some point the voltage should increase to kick the sled
    forward. Maybe there's a mechanical obstruction, maybe you still have wiring

    Mark Z.
  3. N_Cook

    N_Cook Guest

    I changed the position of the central limit switch action point by 1.2mm
    and the same play for 2 mins only.
    The Denon optical unit , marked Sanyo, does not use the usual
    double-rack anti-backlash arrangement but a much cruder sort of sprung
    plastic arm tensioner via the mount of the final double cog. I had to
    remove the second rack on the KSS213 to fit in the available space. The
    tension is now too high, the rack must be .5mm or so wider, and I'll
    have to find a way of backing off the tension. The final cog to the rack
    is 12 teeth and I can feel resistance 12 times a rev. Running the motor
    continuously , even at low V,the inertia overcomes that lumpiness, but
    that is not representative of the normal radial stepping drive, as you say.
  4. I guess I kind of missed the point of replacing a Sanyo laser with a used

    Bad idea - be surprised if you ever get it to work right, at least with any
    acceptable combination of parts cost and time/effort.

    'nuff said.

    Mark Z.
  5. N_Cook

    N_Cook Guest

    Talk about illogical, machine readable valid em address you deliberately
    don/t spoof in usenet headers but spoofed em address in the body.
  6. N_Cook

    N_Cook Guest

    What a pillock, the racks are 2 different pitches , the KSS213C one
    something like 21 teeth per 20mm and the Denon one is a bit coarser, I
    assumed that all such racks were the same. Whether the final cog will
    swap over,and tooth pitch mismatch betwwen cog and cograther than cog
    and rack, will find out later
  7. N_Cook

    N_Cook Guest

    The Denon optical unit is labelled CD11FTA3N , unless you are aware of
    its Sanyo number , they are expensive to replace, presumably specials
    produced by Sanyo and consequential markup.
  8. N_Cook

    N_Cook Guest

    I melded together a 1.25mm pitch cog with a 0.95mm one with only about
    ..2mm ecentricity but much the same result.
    I've now noticed why pre-selecting track 2 or 5 or whatever results in
    no play. The sledge is propelled to the periphery as though track 10 was
    selected, so something wrong in the interpretation of "0" track data ?
    or something beyond any resolution by me unless anyone has any insight?
  9. chuck

    chuck Guest

    The cheapest I found one for is $89.00 U.S. with free shipping. That's
    cheaper than hours of labor trying to make incompatible parts work.
  10. N_Cook

    N_Cook Guest

    The cheapest I found in the UK was , with all the usual extras about 90
    pounds. Much more interesting playing around/hacking. No guarantee that
    there is not some sort of random ps or other surge that knocked out the
    original laser and could equally do the same with a 90 quid replacement

  11. You could try just looking at various Sanyo pickups on eBay and probably
    find it there under the SFP or whatever number.

    Mark Z.
  12. N_Cook

    N_Cook Guest

    The number on the Denon Sanyo one is SF-P101N but as that is on the
    plastic of the body rather than a label, there may be a lot of flavours.
    The optical unit just carries the laser , the receive photodiode matrix
    , and the focus+track coils. Could the track coil polarity be wrong?
    2 minutes in could be where the sledge has to definitely have moved as
    come to the limit of the coil shift ambit, worth a try . Now what
    differentiates the orthogonal coils? A small voltage in each to see if
    the lens moves vertically or radially I suppose. Nothing like
    heuristics, its not as though the owner is paying for my farting about.
  13. N_Cook

    N_Cook Guest

    Same 2V polarity on lines 1 and 4 of the ribbon send the focus the same
    way and same for lines 2 and 3 for the track throw for both optical
    blocks, so nowhere left to go
  14. N_Cook

    N_Cook Guest

    The SM (listed RCD M33DAB) has the test mode details. May as well try it
    as does not seem to require a test CD. although at no stage has it
    registered one of the 20 listed error codes
  15. N_Cook

    N_Cook Guest

    In the meantime
    It all seems mighty weird that you can progress flawlessly through the
    test routines along with never any error statements but the unit does
    not work.
    Test routines pass byte info out on focus balance, focus gain,track
    balance , track gain , focus offset , track offset,RFRP and a routine
    that sums errors in a 2 second sample. Go into the auto adjust routine
    after adjusting the power pot and the values change. I don't know what
    100% error figures for 2 seconds would be ,but readings about 023,000
    one time then adjust pot and then average about 035,000. So if 6 digits
    is 100% then about 2 to 4 percent. What would a representative figure be
    for dust,microscratches,scatter etc ?

  16. You continue to burn large quantities of time on this one. I'd be out of
    business in a month if I made a practice of this sort of thing.

    My view: Fix the damn thing and get on to the next piece of crap...

    Mark Z.
  17. N_Cook

    N_Cook Guest

    Sanyo one in there and working all functions. So bulk standard cheapo
    with no added Denon flavour it would seem.
    BER error now about 100
  18. N_Cook

    N_Cook Guest

    whole deck.
    Quite happy with BER of <>100 but I assume this error reading would be a
    good monitor , not immediate though, for adjusting the power pot for

  19. Finally!

    Mark Z.
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