[mythtv-users] Two mysteries

[Mike Perkins]

On 28/04/13 18:21, Matt B wrote:
> Hi folks, In the face of plummeting WAF and rising frustrations I'm appealing
> to you to help me solve two mysteries plaguing my mythtv.
>
> First the background: My recently retired mythbox ran for several years with
> excellent reliability.  I have all my AV gear in another room and I control
> it all with a wired IR repeater (the Xantech dinky link).  I was using an MCE
> remote receiver (the big blocky one that came with a model 1039) and
> everything worked fine.  However, I was looking to add more storage and my
> case was already bursting so I decided it was time for an upgrade.  I chose a
> mini-ITX motherboard (DQ77KB) with a DC power input from an laptop style
> brick.
>
> I finished my build and plugged in the MCE remote receiver but it didn't
> work.  The little LED on the MCE receiver said that it was seeing button
> presses but they weren't being relayed to the OS.  I tried several different
> things with LIRC but concluded that somehow the USB3 ports wouldn't work with
> this ancient remote receiver (possibly incorrect conclusion).  My old box was
> running ubuntu 10.04 with mythtv 0.24 while the new one was ubuntu 12.04 with
> 0.25.  What also happened when I plugged in the new mythbox is that my dinky
> link was registering button presses randomly as if there was a remote being
> pressed randomly.  I discovered later that the new mythbox was causing the
> spurious signals, whenever I powered off the new mythbox the dinky link
> stopped seeing bogus signals.  About a week after I converted my old mythbox
> into a remote frontend with the new machine as master backend/FE the old
> machine died.  So now I have a FE/BE machine with not remote control (except
> mythmote android app) and a little LED on the dinky link that flashes
> randomly 24/7.  Both together are sinking the WAF.
>
> Mystery #1: With my new mythtv box turned on but disconnected from HDMI and
> ethernet (so the only cord attached is the DC power cord) my dinky link IR
> repeater is firing randomly.  It is worse when I'm playing back content and
> seems to be quieter when the mythbox is idle.  I thought electro-magnetic
> noise might be coupling from the new mythtbox into the dinky link.  So I
> tried wrapping the dinky unit in tin foil but that didn't help.  Then I
> wrapped the AC/DC power brick and my network switch in tin foil but it didn't
> help.  So now I'm thinking that somehow the mythbox is putting a ton of noise
> onto the AC lines and that's how it is messing up the IR repeater.
>
> Mystery #2: Based on the failure of my MCE receiver I bought a FLIRC IR
> receiver.  However when I plug it in to the mythbox it receives bogus key
> presses such that I can't program it.  I've tried covering every LED I could
> find with electrical tape but that didn't help.  If I plug the flirc into my
> laptop then I can program it successfully but when I plug it back into the
> mythbox it keeps on getting random button presses.
>
> If the new mythbox was emitting IR randomly then that might explain both
> symptoms but I've done everything but wrapping the whole machine in a light
> proof bag.  I guess that'll be my next step but maybe these two problems are
> not related? Any suggestions and/or brilliant ideas?
>
I'm not sure USB3 ports are always backwards compatible with USB2. On my
motherboard there is a BIOS option to select whether you want the ports to be
USB2 or USB3; YMMV.

Try using a different set of ports if you can, to eliminate this possibility.

-- 

Mike Perkins