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Sony BDV-E300 Blu Ray Home Theater

Discussion in 'Troubleshooting and Repair' started by Mandinca, Jan 9, 2014.

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  1. Mandinca

    Mandinca

    3
    0
    Jan 9, 2014
    I was recently given a Sony BDV-E300 blu ray home theater “in a box”, complete with the speakers, cables, remote etc.
    However, when I was given it I was told it wasn’t working and that there was some kind of error where the main system didn’t think the speakers were connected when they were.
    When I got it home I hooked everything up and turned it on – nothing. Not even a standby light.
    I asked the previous owner and all they could tell me was that when they gave it to me it would power up but there was an error message about the speakers.

    I can’t find a schematic online anywhere and just wondered if anyone had any useful suggestions for where to start looking for faults.
    Presumably the output side of the transformer but after that I’m at a loss.
     
  2. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    Hi Mandinca,

    I dont know how much experience you have with electronics so do be careful with mains operated equipment. Do not attempt repairs unless you know what you are doing old bean.

    From first principles, please post a photo of the circuit board (unplug the unit, remove the cover, which will involve unscrewing a bunch of phillips screws) and let us see what occurs under the hood. You are looking for obvious things to begin with such as a stray bit of wire from an old speaker cable causing a short somewhere or, my favourite thing to look for as it is so common in such equipment, defunct electrolytic capacitors (which look bulged or crack on top or sometimes leak gunge when damaged).

    There are serious experts on this forum more than capable of remotely diagnosing and helping you repair the unit, but it would help if you provided some meaningful data at least in the form of a photo of the main circuit board (including the power supply module...in fact, a photo of everthing under the hood) :D
     
  3. Mandinca

    Mandinca

    3
    0
    Jan 9, 2014
    Thanks quantumtangles, how do I tag you in a post ?
    Anyway, I have extremely limited electronics experience but know a little about how to use a digital meter. So, I popped the bonnet (I was born and grew up in England before relocating to the US a few years ago). Plugged the unit in and started off testing that I was even getting power to the main board. I am, 120 VAC so that's ok. After that I removed the front cover so I could access the back of the on/off switch and couldn't find any power either AC or DC. I would have thought that there was a transformer converting to 12VDC somewhere but since I have no diagram.....
    The way I checked for power to the on/off switch was I grounded one probe to the chassis and put the other probe on either side of the switch. One side had 0V the other had 0.9V.

    I did a thorough visual inspection for pieces of speaker wire, burnt components etc, can't see anything obvious. It doesn't smell if I leave it plugged in.
    I've searched all over the internet for a wiring diagram for this unit but so far only come up with, what look like, untrustworthy sites that want to sell it to me.

    I've attached a few pictures, hopefully you can make sense of them.
    Any help you can give me to diagnose this is appreciated - seems a shame to throw it away and Sony want a "minimum" of $120 to repair it.
     

    Attached Files:

  4. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    The pictures are not very high resolution so I cannot zoom as much as I would like.

    The problem may very well be with the power supply board (the largest of the two light brown or sand colored boards with the yellow transformer on it). stay well away from this board if it is plugged in as it is extremely dangerous.

    You will see your 120v mains supply attached to this PSB board (to the power supply board) by means of the silver mains lead and a two wire (two-pin) connection to the PSB. These two wires (the black wire and the white wire) join the PSB in that white two pin socket plug connection. This is where the mains electricity enters the device. They are your two mains AC wires, live and neutral. The danger zone.

    Thereafter, the regulated output voltage (12 volts or whatever it may be) exits the PSB via the five-pin to four-pin red and black wires. I suspect everything on the sunny side of that four pin connection is fine and the problem lies in the PSB. It may well be that no or no adequate voltage is leaving the PSB and getting to the rest of the device.

    Absent other information, I would begin by reading a book by an experienced engineer about fixing domestic appliances. You should be able to download one for a couple of dollars from Amazon via Kindle.

    I would first check the upper voltage specifications of the radial electrolytic capacitors (just by reading the information on the side of each cap) to give you an idea of what sort of voltages you may be dealing with (after the PSB has supposedly done its magic and supplied power to the rest of the device).

    They should be relatively low voltages, and though I caution against checking these voltages with a multimeter, if you do so please do so with great caution (though I advise you to instruct a qualified electrician).

    So you just may safely be able to check (with a Digital Multimeter) the voltages in play on the circuit board beside the PSB (do NOT try and check the PSB itself when it is plugged in - WAY too dangerous, in fact the entire exercise is dangerous and should not be attempted unless you consider you have the skill to do it. (I caution against it but I am not your keeper).

    If you are unable to identify any voltage whatever in the circuit board beside the PSB, that would tend to indicate a fault in the PSB.

    If my guess is right, you would then have two main options. First, get a replacement PSB of the correct specifications on Ebay and replace it. That should cost no more than about $30 dollars.

    The second alternative, if you are feeling intrepid, would be to consider replacing the radial electrolytic capacitors (not the very large one to begin with) on the PSB obviously after unplugging the device and removing the sand colored circuit board.

    I say this because there appears to be writing in Mandarin on the side of the Electrolytic capacitors indicating they were made in China. Some Chinese brands of electrolytic cap are notoriously unreliable, often lasting only a couple of years at most. Although they all seem to look ok, if they are made for example by Capxon (I think that is the name) I would replace them all, as it will only cost a few dollars to replace them and it is an interesting weekend project.

    The radial electrolytic capacitors on the power supply board are cylindrical with aluminium tops and most appear to be black though some may be purple or blue etc. They will be marked with the upper voltage limit on the side of each one (that is, how high the voltage can go before they will definitely fail) as well as their capacitance in micro-farads (uH) (how much charge they are designed to store and release). The values will probably range from about 10,000 uF for the massive cap on the PSB to perhaps 10uF and 47uF through to 3,330 uF elsewhere. Measuring instruments are available to check whether capacitors have failed or not but they tend to be very expensive and often you must remove the caps from the board before testing them. You could begin by removing one or two you are most suspicious of and then checking the knowledge base on this site to learn how to check them with various instruments (very basic tests can even be done with a multimeter though they are not very accurate).

    Again you should not attempt any work on mains equipment without being extremely cautious and only if you consider you have the appropriate expertise and safety awareness.

    If you decide not to proceed, why not remove some of the components for other projects such as the DVD drive and maybe some of the more exotic components.

    Kind regards

    Edit: try and get hold of a mains rated multimeter with clip on connectors so you do not have to actually touch anything if you decide the plug the device in to test voltages. Keeping your hands away from the device, and certainly keeping both hands away from it at once, is key because electricity might pass through your heart and could kill you if you use both hands.

    Edit: Note that electrolytic capacitors (unlike several other types of capacitors such as ceramic capacitors) are pole sensitive, meaning that they must be connected the right way round (they have positive and negative terminals). Getting them the wrong way round means they will not work. they are marked with a negative sign on one side to help distinguish which way round they go. New ones normally have a slightly longer wire on the positive side but as these caps are already attached to your circuit board they will have had their wires clipped.

    Edit: Also I would replace the glass fuse beside the power terminal input on the PSB as who knows, it may have blown and could be an easy fix (replace with an identical fuse)
     
    Last edited: Jan 11, 2014
  5. Mandinca

    Mandinca

    3
    0
    Jan 9, 2014
    Thanks, a lot of useful information there and a worthy warning. I checked the glass fuse and it shows no resistance across it so I presume it to be ok. I suppose it couldn't hurt to replace it next time I'm at Radio Shack (Tandy).

    The four pin plug with the two red and two black wires......the two red wires are marked 31.5V on the board and the two black are marked P-GND.
    I put my meter both across the red to black and also the red to chassis and got nothing but mV. So, no power getting to the second board presumably.
    So, not only do I have a fault in the PSB but there's also the original fault that the previous owner told me about with there being an error coming up on the display to do with the speakers. Also, the capacitors are set in such a way that I can't read the labels on them.
    I think I'll have a look around for a replacement PSB rather than trying to blindly repair the one I have, or at least talk to my electrical engineers at work to see if they would be prepared to have a look at it without a schematic being available.
    If I can get it to power up again then maybe I can fix the other problem.

    Having pulled the PSB out there are no markings on it that I can find any reference of online.....
     
  6. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    There is a bridge rectifier on the PCB (the four black diodes in two pairs) which converts the 120v alternating current into what I imagined would be 12 volts or more of direct current. I did not think the DC would be as high as 31.5 volts for that application but no doubt you are right about that.

    The fault might not be the electrolytic caps (guessing can be unhelpful and time consuming). It might for example be a failed varistor (voltage limiter) if for example someone has plugged the device into a 240v supply in Europe or if there has been a lightning strike with the device plugged in. Check out wikipedia to see what varistors look like and then perhaps check to see if any of the varistors on your PCB look damaged.

    Replacing the PCB would probably be optimal but you will likely need a proprietary PCB rather than a generic replacement (note the discrete power supply that enters via the thin white wire bundle to the other circuit board.

    Best of luck with it.
     
  7. davenn

    davenn Moderator

    13,580
    1,868
    Sep 5, 2009
    No, not quite correct. ;)
    This is a switchmode PSU, actually in this case there appears to be 2 SMPS's on the same board. the DC voltage on the output of the bridge rectifier is likely to be up ~ 200 - 250DC. The voltage rating on that BIG black electro capacitor in the lower right corner will be rated a little bit higher than the working voltage of the circuit its in.

    [​IMG]

    OK above is the PSU board sectioned off into its various parts

    there's several DC outputs off the board, that twin red and black wires are the main PSU to the amplifier board
    Theres a white twin that feeds power to that black thing and tuner in the top left of the case in pic 1
    and finally a multi pin connector supplying various voltages to other parts of the system

    None of your pics are in focus, so I cant read any markings on the board for volatges at various places

    cheers
    Dave
     

    Attached Files:

    Last edited: Jan 12, 2014
  8. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    Thanks for correcting my post Davenn. I shall have a more careful look at the theory and practice of switch mode PSUs :D
     
  9. quantumtangles

    quantumtangles

    152
    3
    Dec 19, 2012
    This is the manual for the device (unfortunately not the service manual).

    http://www.sony.co.uk/support/en/product/BDV-E300/manuals

    Fairly useless.

    Service manuals (containing schematics) are on sale from about $15 dollars from:

    http://www.manualuniverse.com/manag...8&shwBt=0&xpageG=15&xmdelG=BDV-E300&xmrcG=184

    and from:

    http://sparedparts.com/parts/details/sony-bdv-e190-e290-e490-e690-service-manual-complete

    Be careful that sites do not try to pass off the 'user manual' (which essentially tells you how to plug the device in and operate the remote) as the service manual which contains the schematics, as there are a lot of useless manual selling sites about :D

    The service manual may have been available for free on filetube but the government have shut down access to that site from the UK because of alleged music copyright violations :D

    Edit: Even if you get hold of the service manual, it is possible they may have drawn up block diagrams instead of detailed schematics
     
    Last edited: Jan 12, 2014
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