According to https://www.modmypi.com/shop/raspberry- ... s-Adaptor) is not.aaa801 wrote:Is your powered hub backpowering?
I forgot to mention that I'm not using HDMI but Composite video, and unfortunately, I don't have a volt/multimeter.johnbeetem wrote:Take a look at this entry at the RasPi Troubleshooting Wiki: http://elinux.org/R-Pi_Troubleshooting# ... VI_monitor
I have this happen when my TP1-TP2 voltage drops below 4.65V. If you have a volt/multimeter, check TP1-TP2: it should be at least 4.75V for reliable operation.
You may be able to fix the problem by editing the config.txt file to set config_hdmi_boost=4, as suggested by the Wiki.
No, those points will already be connected. You need to connect either of those to a real ground (i.e. something connected to a mains earth pin).jjggag wrote:Ok, I just tried to connect the outer part of the composite video to TP2 (ground) in the raspberry using just a piece of wire with no results.
Its very annoying because apart from the static/snowy image, I also get buzzing (sound).
I've seen the description and the photos.jjggag wrote:Scenario:
Raspberry model B powered by 1A usb.
Hard drive: 2TB WD20Ears 3.5'' so I use this adaptor from sata to usb: http://dx.com/p/usb-2-0-to-sata-ide-5-c ... 113?item=8 so it's self powered.
Do I need a better usb hub providing more Amps? even when the hd is self powered? Or what do you think is the problem? Thank you very much in advance.
From the TV loudspeaker though is a constant buzzing, no matters if I volume up, it doesnt sound louder. It only goes away if I press mute on tv.How are you hearing the buzzing sound? From the TV loudspeaker, from the power supply, from the hard disk, ...?
Yes, I use that power supply, it's low quality/cheap but actually it works, and no other problems when using it with a laptop.Did you use the power supply in the photo to power the hard disc drive?
The TV set you're using uses an earthed plug or has only two pins for the main socket? It's an LCD or CRT model?
I used some plug adapters not to use the third pin (earth) on 1 of the sides, and still the same.If both these thing are true a connection earth -> tvset -> composite cable -> pi -> usb cable -> usb hub -> SATA adapter -> hard disc -> power supply-> earth is made. This connection is a ground loop. Colul be a mess to get rid of it.
If I dont use the usb hub and I connect the hdd directly to the raspberry, same happens.Static/snowy image, buzzing sound ...
I'd be wondering if the PSU for the hub is putting rubbish on the ground connection - at its switching frequency or a multiple.
As I commented, I'm not into electronics so I still don't know how to do this, but probably u're right and that would solve it. I can use a piece of wire, put an end in the outer part of the rca cable and the other one??have you tryed earthing the composite cable yet?
You may just have a duff/damaged composite video cable. Can you try another one? For testing it doesn't need to to be a video quality one. If you have a stereo audio cable with a pair of RCA phono plugs (typically red and white but sometimes red and black) at each end, that will do. Just use one plug at each end; same colour of course!jjggag wrote:I had the opportunity to connect the raspberry to a monitor through hdmi, keeping the rest of the configuration. It worked! noise/snow disappared. So obviously is related to the composite video cable.