[mythtvnz] Help troubleshooting signal interference

[Tortise]

Could it be the PSU has a component with a heat related fault?  I'd suggest try swapping it out with another and see if problem persists.
Kind regards
David

  ----- Original Message ----- 
  From: Matt Poff 
  To: MythTV in NZ 
  Sent: Saturday, February 07, 2009 11:46 AM
  Subject: Re: [mythtvnz] Help troubleshooting signal interference


  It's fairly grunty - a RaidMax 380 Watt unit:


  http://www.tigerdirect.com/applications/searchtools/item-Details.asp?EdpNo=1648607&sku=R456-1002


  Not near the machine currently so can't try disabling the additional SATA. Here are the system specs of the box:


  AMD Athlon 64 X2 Dual Core 3800+ Socket AM2 Processor 
  Geforce 7600GS 256MB DDR3 Graphics card 
  1G DDR2 667 RAM 
  320GB SATA2 7200rpm HDD 
  18x DVD-R/+R, Dual Layer DVD writer 
  500W Raidmax Power supply 
  MSI K9N Neo-F Motherboard, Socket AM2 Motherboard 
  Silverstone Lascala SST-LC16S-MR ATX Home Theatre Case, Silver (has 2 built-in fans).


  Not convinced it's an under-powering issue though as I wouldn't expect to see the interference still occurring on the TV video-input when the Myth box is powered down (but still plugged in with the main power switch on).


  Noticed a few posts on the web where people were reporting electrical leakage into ATI graphics cards affecting outputs. I'm wondering if an earth from a case screw onto the RCA-connector (plugged into the S-Video->Composite converter that came with the Gfx card) might be worth a try. Still - it's run fine for a year and a half so can't understand why it's a problem now. 


  Will take a DVI monitor home and see if that outputs signal OK - perhaps the aforementioned converter is faulty?


  Matt




  On 7/02/2009, at 11:30 AM, Douglas Pearless wrote:


    Are you running near the limits of the power supply? (What size is it?  
    If it only requires a 4 pin extra power plug for the motherboard, then I 
    have a spare you could borrow to troubleshoot).

    If you remove the extra sata drive, does this fix it?

    Douglas.

    Matt Poff wrote:

      Over the last couple of weeks my MythBox has developed some weird  

      signal interference which obliterates the picture feed to the TV.  

      There have been no electrical wiring changes in the house or new  

      appliances plugged in so it's a mystery. I unplugged every other  

      device from the mains running off the same dual socket except the TV  

      and Myth box and unplugged everything else (audio jack, DVB-S feeds  

      etc.) from the box but the interference persists even when the Myth  

      box is not running.  I even grabbed an extension cord and fed the TV  

      and Myth Box of completely different loops with no effect. Only when I  

      actually turn off the power switch at the back does the interference  

      stop.



      I opened the box up to check whether there were any loose cables etc  

      but couldn't find any. The only change I've made recently was adding  

      another SATA drive to the rig.



      I'm assuming the problem stems from the power supply but not sure how  

      to fix it? Do I need to ground the box in some way? It's a purpose- 

      built PVR case (Silverstone LC16M) so should be fit-for-purpose.



      The actual supply of power is fine and the system runs but the feed  

      out to the TV is borked. Turning the RCA jack  (good quality video  

      gold-plated) in the Video-In socket sometimes improves the picture  

      fleetingly. If the system is unplugged from the mains and left for 10  

      minutes or so the signal is usually OK on the next restart for half an  

      hour or so before the interference kicks in.



      Any ideas how to fix or further troubleshoot this?



      Cheers,

      Matt







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