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Thread: Cant get my blue ray working because of amp. Anyone ?

  1. #1
    Join Date: Feb 2018

    Location: Bucks

    Posts: 71
    I'm Alex.

    Default Cant get my blue ray working because of amp. Anyone ?

    Edit: following the recommendations from snowman I isolated the issue to be more likely with the AMP, not with the BR. subject changed.

    See the update: http://theartofsound.net/forum/showt...561#post973561


    ~~~~~Original Post~~~~~~~~~~~
    Hi,

    I’m unable to connect my new Blu-ray UBP-X800 player to the existing audio/computer setup. My main power circuit breaker kicks in and jumps the fuses when I use both HDMI and digital audio coax of the Sony. Here is a brief description of my setup, please see the diagram below.

    I have a good sounding combo of a DAC plus a 40-year-old 2x70W integrated amp/receiver. The amp has a two pin EU power plug, no grounding.

    The Blu-ray has the normal three pin UK connector, however the ground pin is plastic and is not connected to anything. The LCD screen is the only device that has a three pin power lead with the actual ground pin connected, so I guess that’s the only ground in my system.

    • If I disconnect the digital coax from the DAC, Blu ray plays fine on the LCD.
    • If I disconnect the HDMI from the LCD, Blu ray makes an amazing sound through the DAC + AMP (I obviously need to power up the DAC)
    • If I have both HDMI and the coax SPDIF connected to the DAC and LCD, then turning on the AMP activates the power circuit breaker.
      • This happens even when the DAC is not connected to power (see the diagram) and even when both the LCD and blu-ray are not turned on. As long as the LCD and Blu-ray are connected to the power the problem exists.
      • Disconnecting the Gnd wire between the DAC and Amp doesn’t change a thing
      • I suspected power spikes when the Amp is turned on, so I tried to turn it on without the coax cable to the DAC and to connect the coax cable when the Amp is alive (the amp is designed to make this old-fashioned click before it can play anything). Connecting the digital coax after the click makes sparkles and brings the circuit down.


    Since both video and audio parts of this system work fine when they are not used together, I am not 100% sure if I can blame the Blue-ray and I am not missing something obvious here. Do you think this problem can be explained by bad cables, amp or DAC hidden problems or design issues or may be by something else?



    Thanks


    blu-ray-problem.jpg
    Last edited by alexk0il; 01-05-2018 at 10:40.

  2. #2
    Join Date: Oct 2017

    Location: Coventry

    Posts: 130
    I'm Mick.

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    Hi , Are they all plugged into the same mains extension lead or are the on different ones?

  3. #3
    Join Date: Oct 2017

    Location: West Wales

    Posts: 86
    I'm Alan.

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    Umm, I would be more than a little concerned here. Earth leak trips and 'sparkles'... Please BE CAREFUL until you know what the problem is. Do not touch any exposed metal parts, cases, connectors etc. with the mains power on.

    The only Mains Earthed component on your system is the LCD. When you connect the HDMI just to the blue ray, the blue ray becomes earthed too. So I would assume the player is OK.

    Then when you connect the blue ray coax to the DAC you earth the DAC and amplifier too. (The earth comes through the screen wire of the HDMI, coax AND signal cables.) So it could be either the DAC or amp at fault.

    Next you say it happens with the DAC disconnected from the mains. And if you remove the ground wire between the DAC and amp. But unless you remove the signal wires too (L/R Line in) the earth still goes to the amp via the screen of the signal cables.

    Next step is to remove the ground and signal wires from the amplifier. If that is OK, power the DAC up too (still with no connections to the amp) and see.

    If that is OK then either the amp is causing the problem or very unlikely the LCD. Remember unplug everything before touching the connectors or cases!

  4. #4
    Join Date: Feb 2013

    Location: W Lothian

    Posts: 99,005
    I'm Grant.

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    Sounds like one is at half mains potential compared to other at either end of cable. Can happen when you have things like a tv that's on say a 2 pin smps and an earthed component. Probably lowish current in micro Amps but get it checked. Also your earth leak trip could be sensitive.
    Get it all checked by a competent technician
    Regards,
    Grant .... ؠ ......Don't be such a big girl's blouse

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  5. #5
    Join Date: Feb 2018

    Location: Bucks

    Posts: 71
    I'm Alex.

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    Quote Originally Posted by Mixc View Post
    Hi , Are they all plugged into the same mains extension lead or are the on different ones?
    All is plugged to the same extension lead except for the BR, see the diagram attached in OP.

  6. #6
    Join Date: Feb 2018

    Location: Bucks

    Posts: 71
    I'm Alex.

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    Quote Originally Posted by snowman_al View Post
    Umm, I would be more than a little concerned here. Earth leak trips and 'sparkles'... Please BE CAREFUL until you know what the problem is. Do not touch any exposed metal parts, cases, connectors etc. with the mains power on.
    ...
    Next step is to remove the ground and signal wires from the amplifier. If that is OK, power the DAC up too (still with no connections to the amp) and see.

    If that is OK then either the amp is causing the problem or very unlikely the LCD. Remember unplug everything before touching the connectors or cases!
    Thank you, Snowman, your recommendation to check ground issues by attaching devices one by one does make a lot of sense and I guess comes from experience .

    The DAC (also powered by a two pin power source) works fine in this setup, which suggests that either LCD or the AMP is to blame. Just to confirm my findings I connected the HDMI ground from the LCD to the Gnd on my AMP. This takes the BR and the DAC out of the equation.

    Yep, it surely does break the circuit when the AMP is powered on. To be on a safe side I used a single tiny OFC wire thread from my multi-core speakers cable and it gave me a nice puff with small yet beautiful sparkles before the wire thread evaporated and the main circuit breaker took over.

    This is quite strange as the AMP has only two pins and I would expect it to float with any ground as long as it is common to all equipment. Considering the sparkles I am now more concerned with not getting myself or my kids accidentally fried if a ground signal somehow comes close to the AMP (unattended HDMI cable, another device with 3 pins plugs nearby, etc.)

    I will try to connect the AMP's directly to the ground pin of the wall socket to completely exclude LCD, but I don't have a spare 3 pin plug to play with, so it will take time.

    Anyway, I think I agree it is very unlikely to blame the LCD, so I am checking the AMP schematics to see what's going on. I can't figure out if this is due to incompatibilities between different variants of power supply unit with UK power sockets or is it because it is faulty indeed. Mine is the Asia/Latin America variant and it does not have the ground in the PSU board (page 14 of the service manual in the link). The last time I looked at something similar was 30 years ago though, so going through the schematics takes a bit of time for me . Just out of curiosity, is the UK main break circuit supposed to kick in when Ground touches the Neutral wire?

    https://www.hifiengine.com/hfe_downl...e_en_de_fr.pdf

    Thanks a lot.

  7. #7
    Join Date: Oct 2017

    Location: West Wales

    Posts: 86
    I'm Alan.

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    OK a few things to think about.

    A warning again. Do Not touch any metal or conductive parts of the Amplifier or LCD when they are plugged in until you know it is safe or repaired.

    First - If you have a multi meter, check to make sure your mains socket is wired correctly. First at the wall socket then at the extension sockets. Test between Live and Earth first, then Live to Neural. (These should be 240 volts ac and very similar.) Then Neutral to Earth. If you measure a large voltage Neutral to Earth (or have a large difference between L - E and L - N readings) there is something wrong with your mains.

    Prove the LCD is not to blame. - If you have a multi meter, ensure the HDMI metal connector is connected to the mains earth pin on the plug. Use lowest ohms range and it should be less than 0.5 ohms. (Alternatively, but not recommended, plug the HDMI lead into the LCD and hold the metal part of the other end of the connector to a known good earth, metal radiator or mains socket screw head etc., and then plug in and switch the LCD on. If it trips the breaker the LCD is faulty.) As before DO NOT touch any metal parts until you know it is safe.

    The amplifier. - Again if you have a multi meter, use the 20K ohms range to measure from the Ground connector on its case first to the live and then neutral pins on the plug. Obviously not connected to the mains. Now if you press the amplifier mains switch on and have a reading of less than 20K ohms on either or both there is something wrong inside the amp. (The alternative is as before, but you must use thick and well insulated wire if you do.)

    I cannot see the diagram you link to so do not know what amp you have still. Best guess / hope is there is an arc suppression network or capacitor across the mains inside the amp that has gone very leaky electrically. But it could be anything - a faulty transformer, an electrolytic capacitor has oozed some 'goop' across a mains voltage connection or failing circuit board...

    An RCD breaker normally responds to a fault across the Live to Earth path. Neutral should be at or near the same potential as the mains Earth, so normally should not drop the trip. If it does do get the mains checked.

    Again, Please Be Careful. Any doubt get a qualified person to sort it.

  8. #8
    Join Date: Feb 2018

    Location: Bucks

    Posts: 71
    I'm Alex.

    Default I guess it's the AMP.

    Thanks a lot. This is amazingly helpful and I am learning quite a lot during the process. As an engineer I do appreciate the way you think and isolate issues one from another.

    1. Voltage between Neutral and Live in mains is ~1.5-1.9V AC (and a few mV DC). The rest seems to be normal.
    2. LCD seems to be fine
    3. Amp - something is going on
      • Switched off - everything is in mega-ohms.
      • Switched on
        • Case Gnd to Earth pin ~0.5 MOhms
        • Case Gnd to Neutral or to Live ~10 Ohms, definitely wrong.
        • Neutral to Live measures ~5-6 Ohm
      • Additionally, case Gnd to Earth on HDMI lead gives 83-85V AC at ~0.2kHz.

    Anyway, I got this AMP for an exercise on how to recap and to regulate it, but because it sounded so good I did not rush to open it up and to risk killing it during the exercise. I guess there is a now a good reason to do it sooner rather than later. The amp goes off the mains till this is sorted out.

    Do you have any other tips that can help to save time in chasing the problem? I hope it's just a broken wire touching something it's not supposed to, but can't tell without opening the beast up.

    Anyway, I know I'm pushing your patience, but just in case, here is the link to the amp service manual

    https://goo.gl/FzJ83i
    Last edited by alexk0il; 03-05-2018 at 19:33.

  9. #9
    Join Date: Oct 2017

    Location: West Wales

    Posts: 86
    I'm Alan.

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    Not a problem.

    I assume your statement, ''1. Voltage between Neutral and Live in mains is ~1.5-1.9V AC (and a few mV DC).'' is a typo and should be Neutral and Earth? If so that is fine.

    At least you know the amplifier is faulty. Lucky you found it before there was an injury... And I can see the diagram too now.

    ''- Neutral to Live measures ~5-6 Ohm'', this is fine too and normal for the primary of this type/rating of transformer.
    ''- Case Gnd to Neutral or to Live ~10 Ohms, definitely wrong.'', definitely!

    When you get the lid off follow the mains lead wiring and look for the obvious failed component, a loose or shorted wire, extra screw lodged between tracks, etc.
    Then the mains switch for signs of 'tracking' (burn marks or cracks that carbonise and become conductive over time).
    Same again at the part for Latin America marked Audio P.W.B(3). Top-ish right hand side on page 14.

    Test the mains transformer next. You need to check A there is no connection between the primary mains winding and either of the two power supply secondary windings. And B that the primary mains winding is not shorted to the metal core of the transformer.

    Unfortunately the only way is to disconnect all the transformer secondary connections, marked 21, 22, 23, 24, 26, 28 and 29, on the diagram, from the 'Audio P.W.B(1)'. Leave the primary ones 9, 6, 4, 3, 1 and 2 connected.
    Put your meter on the 1Meg ohm range and measure between 21 (power supply secondary) and 9 (mains primary) for example. It should read open circuit. And for the other secondary from 28 to 9 again should be open circuit. Anything other than very high resistance here is a transformer failure.

    To check for a short to the core do the same test, but put one lead on the case Earth terminal and the other on 9 (mains primary). It should be open circuit too.
    Again, anything other than very high resistance here is a transformer failure.

    It takes longer to write it than do it, so good luck!
    Last edited by snowman_al; 04-05-2018 at 09:53. Reason: typo

  10. #10
    Join Date: Feb 2018

    Location: Bucks

    Posts: 71
    I'm Alex.

    Default

    Thanks. I am definitely lucky to catch this before an accident. Tuning the amp involves sticking hands inside and turning potentiometers on a live amp.

    I have family staying with me, plus I want to solder/desolder components on a junk electronic board before I gain confidence with my soldering skills. I guess I will be come back with meaningful results in a couple of week.

    I will keep you updated .

    Thank you again,
    Alex

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