SAMSUNG DVD-HD841 SACD Analog Plug Distortion!

Discussion in 'Digital Sources' started by Will2Bl, Oct 7, 2017.

  1. Will2Bl

    Will2Bl New Member

    Messages:
    11
    Hello!

    I have a SAMSUNG DVD-HD841 player that supports SACD and DVD-Audio. Unfortunately, whenever the RCA analog outputs are used, the sound is extremely distorted. The same (non-SACD) sources played using the optical and digital coaxial outputs are clean.

    I'm wondering what the cause of this might be. I'd like to be able to use it as a backup SACD player and am hoping that it is fixable.

    Thanks...
     
  2. Bob

    Bob AK Subscriber Subscriber

    Messages:
    929
    Location:
    West coast
    internal DAC's probably flako. it's only important for SACD playback that only uses the RCA. CD audio
    continues out the optical/digitals.

    this is an excellent unit. Fixing it is another universe - it's all surface mount and way too
    tiny for my eyes. there are however, docs out there with schematics and upgrade how-to's.

    look for muting circuits (don't know if they exist in this unit). I hate muting circuits.
     
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  3. Will2Bl

    Will2Bl New Member

    Messages:
    11
    Thanks for the info, Bob. I am an amateur who managed to switch out some caps and transistors on an amp (probably just barely), but I'm guessing this is another level altogether. Is the DAC a microchip or otherwise higher level of tech?
     
  4. Bob

    Bob AK Subscriber Subscriber

    Messages:
    929
    Location:
    West coast
    there's a service manual available and on p5-1 there's a diagram that has a couple sections
    fed from the DSP (digital Signal Processor) that (end) results in left and right channels signals
    outputs (how's that for plural phrases) but another path takes the digital signals directly out
    to the digital and optical outputs.

    these sections seem to do a bunch of things, I am probably oversimplifying and misleading,
    like process the SACD's DSD into PCM, and do some x-bit processing before
    doing the Digital-to-Analog thing.

    my guess is the only place you could "hear" analog signals is at the end of this signal chain
    and anything before this end stage back to the output of the DSP section is all digital
    and will need a different class of tools to inspect, let alone.determine what's going on.

    if you're willing to play with the unit to try to figure out what's wrong you can pull the
    cover and identify the chips for this general DAC area. use a wooden stick and poke around
    trying the chips and the parts - maybe a loose solder connection - you'll need a magnifier
    and good eyes to look for any possible solder problems. also, if you have freeze spray
    then after warmup (and the sound problem appears) use a narrow spray on each chip
    to see if it's a heat issue (sound clears up after spray).

    you can use an air cleaner (dust buster type) test the spray for coldness - typically when
    duster is held upside down or at an angle.

    when did this problem start, assuming it wasn't a day one problem. second - I'm assuming
    you've verified it's not a (RCA) cable connection problem and the cables test Ok elsewhere.
    next, you've tested the RCA outputs into a known working input. if you use an external
    DAC then swap its cables at the receiver/preamp/amp with the HD841.

    lastly, if all this overwhelms ( I tend to overdo the advice thing - it was an absolute mandatory
    process in the jobs I held), these HD841s are sleepers and are not overpriced in the
    used market - I bought mine on eBay earlier this year for very little $$.

    my best guess is somewhere in the last stages, in the analog section, and that's if the
    sound is correct but distorted - in other words the digital to analog conversion works
    since it's not random noise (bit conversion didn't work). It would be the I/V conversion
    or some signal in that last chip not getting set for the chip or as simple as a bad cap.
    (and very last thing - could be the muting circuit if there is one - these make me nutz).

    if it is a chip, it can be replaced even if its a surface mount, takes a lot of care since
    there are hot-air repair stations and if a soldering gun/iron is used - has to be super
    fine tips, etc. find the replacement chip is either easy (mouser, digikey) or hard.

    Bob
     
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  5. Will2Bl

    Will2Bl New Member

    Messages:
    11
    I certainly could not ask for more thoroughness--this is much appreciated.

    The problem was evident when I picked the player up. It was a thrift store find and I am supposing this issue was the reason it was jettisoned, even though everything else is working fine. I am going to attempt the methods you've described when I get a chance over the next few days and will check back in when I've done the prodding. I did switch cables and moved the unit between different amps just to ensure it was the Samsung itself that was problematic.

    Thanks again!
     
  6. Bob

    Bob AK Subscriber Subscriber

    Messages:
    929
    Location:
    West coast
    OK. since it was an easy find then it can be a test case. IOW if you poke around and it's difficult
    to fix then no harm.
     
  7. Will2Bl

    Will2Bl New Member

    Messages:
    11
    I managed to get the board out with just a bit of bloodshed and inspected it closely. I saw no problems with the solder joints and no warped caps or anything else. Putting it back in and reconnecting, I poked and prodded everywhere with a disc playing, paying close attention to the area you specified, and wasn't able to change the sound one way or another. I will just use the functions that work (a region-free dvd player can be useful at times) and call it a day.

    Bob, thanks again for the in-depth attention to my issue. Awfully nice of you.
     

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