1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Fried Board on HR23-700

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by DenaliMike, Dec 6, 2012.

  1. Dec 6, 2012 #1 of 38
    DenaliMike

    DenaliMike New Member

    6
    0
    Aug 17, 2010
    This was scary tonight. All of a sudden this evening we had noxious fumes fill the house. We got the kids to one area of the house and I started running around to figure out where they were coming from. I determined it was from one of my receivers --- an HR23-700. That unit had stopped working a couple of days ago, I had spoken to DIRECTV yesterday, and they were in process of shipping me a new one. (Unfortunately they say another HR23.) I had not unplugged the one that stopped working. Little did I know what would happen this evening. I could not help but open the box after this occurred this evening. One of the components/resistors is totally fried as well as the surrounding board.

    Has anyone heard of this happening? The funny thing is that this is the only receiver I have that is not in an AV cabinet. i.e., it had totally unrestricted airflow around the whole unit.

    I called retention saying that I had no confidence in getting another HR23 after this situation. It could have been MUCH worse had we not been home and immediately unplugged the unit. They said they could have someone come out and look at the installation after the new unit arrived. I don't know what good that will be as this was internal to the unit with nothing around it. Alternatively they said a could upgrade to a different model, they would pick up the cost, but that would require a new 24 month agreement. That does not seem right as well.

    Thoughts? Recommendations of how to proceed? Thanks.
     

    Attached Files:

  2. Dec 6, 2012 #2 of 38
    jimmie57

    jimmie57 Hall Of Fame

    6,631
    320
    Jun 26, 2010
    Texas City, TX
  3. Dec 7, 2012 #3 of 38
    MysteryMan

    MysteryMan Well-Known Member DBSTalk Club

    8,324
    460
    May 17, 2010
    USA
  4. Dec 7, 2012 #4 of 38
    JeffBowser

    JeffBowser blah blah blah

    2,549
    18
    Dec 21, 2006
    That happened to me with the same make/model of DVR on Wednesday night at exactly 8:00:01PM. It also happened almost exactly 3 years to the date prior with an HR20-700. I have yet another HD DVR in the bedroom that refuses to run on line voltage below 116v, contrary to spec. I don't think the power supply circuits on these DVRs are very robust.

    I'm just having them send me another DVR, of whatever kind arrives. I'm not going to get excited about what model is what until they finally make one that is demonstrably and reliably faster than what the current models are.
     
  5. Dec 7, 2012 #5 of 38
    Ed-Williams

    Ed-Williams AllStar

    75
    0
    Sep 8, 2006
    DenaliMike,

    How did you get that picture of “MY” HR-23-700? ;)

    A few days ago I experienced exactly the same; I spent some time with it and found most components on the power supply showed short circuit, so I gave up and sent the unit home to DTV.

    Your posting came at a time when I was considering checking my home’s electrical wiring, but now I believe it is just the unit. What a shame that the designers of this product did not made it with better protection so it would not catch fire! :rolleyes:

    Good luck with the new unit.

    Regards,
    Ed.
     
  6. Dec 7, 2012 #6 of 38
    TMan

    TMan Legend

    216
    1
    Oct 30, 2007
    Wow. How close was this failure to starting an actual fire? It sure scorched that resistor and the circuit board. Was it "done" at that point or could it have grown into sustained combustion and spread to nearby objects? That's scary stuff.

    The OP didn't mention whether he deliberately had to extinguish anything, but still...
     
  7. Dec 7, 2012 #7 of 38
    moghedien

    moghedien Legend

    208
    1
    Dec 3, 2007
  8. Dec 7, 2012 #8 of 38
    JeffBowser

    JeffBowser blah blah blah

    2,549
    18
    Dec 21, 2006
    It's unlikely that would have sustained a fire.
     
  9. Dec 7, 2012 #9 of 38
    TomCat

    TomCat Broadcast Engineer

    4,153
    100
    Aug 31, 2002
    I agree. A fire such as this is most assuredly a fire caused by a shorted component in the PS. Once the component burns up there is nothing left to create the short (which results in lowered resistance and high current), and it becomes an open circuit instead (infinite resistance and no current). Assuming the component "on fire" doesn't ignite other items close to it (and none of those items are combustible without high current flowing through them) that should be the end of it. Dramatic, yes, but relatively safe, and chance is low that it would burn down the house. Also, the short will eventually trip a service panel breaker, also stopping the current.

    It's not common. I have worked in TV stations (which literally house thousands of pieces of actively-powered equipment) for decades and can count on one hand the number of items that have burned up, or at least have burned up dramatically when there was someone there close enough to experience the acrid smell. And in each case, the scenario was as I described; it burned out on its own and nothing else was affected.

    What can burn up? Theoretically, anything that has power applied to it, including resistors (more likely) capacitors (less likely) or the voltage regulator chip in the PS (most likely). DC voltages and currents are highest in the PS, and lower in system boards, meaning the drama is more likely if the PS shorts. That is also where 110 VAC is converted to lower DC voltages. Sometimes a cooling fan bearing will freeze, and overheating causes resistive components to change value, starting a vicious cycle of more current, more heat, etc.

    But it does make one a little uncomfortable that we have electronic components running 24/7 (DVRs) that we can't shut off when we leave the house like we can the TV or dishwasher. There is a lot of UL-approved safety in place, but that's hardly a guarantee of no drama.
     
  10. TMan

    TMan Legend

    216
    1
    Oct 30, 2007
    Thanks for the response, TomCat.

    And these days, so many things aren't really "off" when they're turned off, such as televisions and stereo equipment.
     
  11. dennisj00

    dennisj00 Hall Of Fame

    9,679
    190
    Sep 27, 2007
    Lake Norman, NC
    There's a lot of items in the typical house today that are 'on' 24/7. My house looks like a starfield with the LEDs or other lights twinkling at night. Items have a timer or some minimal use of electricity. Coffee pots, Microwave, dishwasher, stove, refrigerator are just a few in the kitchen with at least an LED or LCD display.

    Unless you unplug an item, turning off a surge strip or some other switch is no guarantee that a surge can't jump the switch gap to fry something downfield. And the damage doesn't necessarily show up after you hear the thunder.

    We had a tree by the garage struck by lightning a couple of summers ago. Nothing smoked or caught fire in the house, but I was finding and replacing telephone and network problems / equipment for six months.

    It's amazing we don't have more house fires.
     
  12. Rich

    Rich DBSTalk Club DBSTalk Club

    26,119
    463
    Feb 22, 2007
    Piscataway, NJ
    Look at the picture again. That little round black thing on the right bottom of the picture is the fuse that's supposed to protect the Power Supply which is where the burned resistor is. They do protect it, but no correctly, obviously.

    Rich
     
  13. Rich

    Rich DBSTalk Club DBSTalk Club

    26,119
    463
    Feb 22, 2007
    Piscataway, NJ
    No matter how you look at it, the fuse should have blown. It obviously didn't and I'd be concerned about that. Hmm. If that resistor flashed open, the fuse might be pardoned for not blowing. Not sure about that, have to see a drawing to know for sure.

    Rich
     
  14. Rich

    Rich DBSTalk Club DBSTalk Club

    26,119
    463
    Feb 22, 2007
    Piscataway, NJ
    One of the reasons my home and it's contents are insured for ~ one million dollars. I've only had one HR start burning, it was a 21-200 and put out enough smoke to wake my son up. Thankfully.

    Rich
     
  15. TomCat

    TomCat Broadcast Engineer

    4,153
    100
    Aug 31, 2002
    You're most welcome, and also correct.

    The difference between a TV turned "off" or a computer monitor in sleep mode vs. a DVR is that the DVR is fully powered all of the time (even though the front panel may be dark), and that the TV or computer monitor is powered by a mere trickle of current until turned fully "on". My point is that the odds are much greater of this happening to something like a DVR that never turns off, even in the current DTV sleep mode, which apparently doesn't do much and does not really save power other than if connected to a TV that powers off when the video signal drops. I try to keep my "vampire" wallwarts plugged into a power strip that I can shut off, but DVRs can't be, practically speaking.

    The good news is that DTV is listed just today in the list of STB vendors that are pledging to find ways to cut power consumption and there is legislation pending behind that. I still don't know how you run a DVR that way, unless you spin down the HDD and then spin it back up just before a recording happens, keeping only the timer circuit powered all of the time. Possible, but maybe not enough to really address the problem of safety all that much. Time will tell. You also need an OS that can sleep.

    Another thing is that what may appear to be a fuse is really a surge protector or a breaker. Gradually-increasing current will pass right through that, and some fuses are poorly rated, letting this sort of damage occur before firing. They can fail also. There is a point where higher current can pass through a fuse (below its rating) and still do damage. The reason is that you can't use a fuse rated just above the normal current requirements, or then you have an issue of fuses popping every time the wall voltage fluctuates just a little bit. The PS regulates a wide range of house AC voltages into unwavering (for the most part) DC voltages, but failed components in the PS or even the system boards can still allow enough current to burn stuff up. Fuses are not foolproof.

    Many of the PS failures are due to fluctuating or surging AC from the wall. A UPS will help, but is also not foolproof, since the PS can still fail even if only fed proper AC voltages.
     
  16. TomCat

    TomCat Broadcast Engineer

    4,153
    100
    Aug 31, 2002
    Well, Rich, the odds are a little higher for a guy with 700 or more DVRs on his account. :)
     
  17. zhezhang

    zhezhang AllStar

    70
    0
    May 8, 2010
    I don't see a fuse in the picture.
    That black round thing on the right bottom looks to me like a torx head mounting screw for mounting the PCB to the chassis.
     
  18. jimmie57

    jimmie57 Hall Of Fame

    6,631
    320
    Jun 26, 2010
    Texas City, TX
    +1
     
  19. Rich

    Rich DBSTalk Club DBSTalk Club

    26,119
    463
    Feb 22, 2007
    Piscataway, NJ
    Didn't the Ultimate TV DVRs actually shut down?

    Nope it's a fuse. Pop the top of that little round black thing and you'll see the fuse link. I did it because I was surprised the PS didn't have a glass fuse such as you see in the earlier models.

    Actually, I trust fuses more than CBs. Just an opinion. They do die after a while. You don't need a fuse rated above the normal current requirements, you need a fuse that will not blow when inrush current comes into play. There are a variety of fuses out there that allow for that. Most are called "time delay" fuses.

    Rich
     
  20. Rich

    Rich DBSTalk Club DBSTalk Club

    26,119
    463
    Feb 22, 2007
    Piscataway, NJ
    I hear that. Yeah, that's why we got that policy. I don't think I'll ever forget that 21-200 smoking away in my son's room.

    Rich
     

Share This Page