Beaglebone black HDMI/VGA converter problems

[lee jones]

Hello all :) (newbie alert btw!)

I've just recently (only in the last few days) bought a beaglebone black and also a mini hdmi to normal sized hdmi cable to go with it. Unfortunatly I'm not managing to get any display with an HDMI to VGA converter however.

I can confirm the beaglebone is doing something as I was able to connect it to a TV with HDMI input, and it displayed a picture ok.

After looking into all of this I noticed this page regarding HDMI to VGA converters - http://circuitco.com/support/index.php?title=BeagleBone_Black_Accessories#HDMI-VGA_Adapters . My HDMI to VGA looks very similar but not quite the same to that converter, in fact it looks rather like this - http://www.amazon.co.uk/Adapter-Laptop-Power-Free-Raspberry-support/dp/B0088K7QUQ/ref=sr_1_2?ie=UTF8&qid=1371231750&sr=8-2&keywords=HDMI+to+vga

One difference I noticed is that the one linked to in the circuitco webpage appears to be powered (presumably by the micro usb port on the converter?). Mine dosen't have that at all; btw originally my converter was bought to be used with the rasberry pi. Since one converter is powered and the other isn't am I right in assuming that the beaglebone dosen't supply the neccecary +5V to power a device connected to the HDMI port at all, hence the failure?

This is only speculation but prehaps most of the HDMI to VGA converters originally bought for rasberry pi's and then subsequently used to try to work on the beaglebone black won't work  at all?

ljones

[Gerald Coley]

The ones listed work. If it isn't listed, then either it did not work or we did not test it. It MUST be externally powered.

Gerald

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Gerald

 

ger...@beagleboard.org

g-co...@ti.com

http://beagleboard.org/

http://circuitco.com/support/

[dfqp...@gmail.com]

i got the same problem, but now i get my BBB over a vga monitor using unpowered converter :)

[kelton...@embarqmail.com]

I just bought a BBB along with a HDMI to VGA converter from Adafruit (long with the other accroutrements). The converter is very similar to the one pictured on the web page as compatible:.http://circuitco.com/support/index.php?title=BeagleBone_Black_Accessories. Note the one pictured is unpowered, or at least appears to be so, so I figured I would be fine. As you can guess, I have no video (sigh)

 

Is there no way to get this to work with the unpowered adapter?

 

The adapter cost almost as much as the BBB and I can't return it. Oh well...

 

Kelton

[kelton...@embarqmail.com]

I stand corrected. I clicked through all the links, and the one they show *is* the USB-powered adapter, as sold by Amazon (made by Cable Matters). That's not what Adafruit sells, alas.

 

Kelton

[fordch...@gmail.com]

After a lot of frustration, I have finally got my HDMI to VGA adapter working.  At first I got a very inexpensive adapter from Meritline.  I could get the initial splash screen, but then nothing. Then I got a recommended adapter and cable that cost twice as much.  I could get the initial screen for a few minutes, but then it disconnected.

Reading a post on Sparkfun, I realized that the adapter was pulling too much current through the Beaglebone.  I touched the capactors next to the HDMI port, and they were very, very hot just before the VGA monitor lost connection.  So I took the adapter apart to find where the 5 volt power was coming in.  A little checking and I found which pin supplies the 5 VDC to the HDMI cable.  I traced the pin out to the adapter circuit board.  Then I cut that wire and soldered a wire onto it.  I ran that wire to the Beaglebone circuit board where the barrel connector connects power in.  I connected the wire up, powered up the board, then powered on the VGA monitor, and everything works like a charm now!  The Beaglebone Black just can't supply enough 5 volt current to run the adapter, so it needs to be powered directly from the 5 vdc source.

[fordch...@gmail.com]

I agree with the post below.  However I am now using a cheap Meritline HDMI to VGA adapter and powering it from the Beaglebone Black 5 vdc power source.  I just had to hack into the adapter and find the wire that supplies +5vdc.  I soldered a wire from the power barrel connector to the adapter circuit board, and now it works great.

[AGSCalabrese]

..... where is the board revision # printed on the PCB ?   I have looked all over the PCB with a magnifying glass.  If the revision is not silkscreened.... why not ?

99guspuppet

[Donald Jacob]

On the side of the GPIO connector there is a white label with serial
number (?) and the revision, A5C on one of my and A5A on the other.

Don

[fridayfo...@gmail.com]

My hopes of using a cheap vga monitor drifted away when my HDMI to VGA converter shut down within a few seconds.  A peek at the BeagleBoneBlack schematic shows a 100 ma resettable fuse guarding the mini hdmi power pin.  It's the yellow thing that looks like a ceramic capacitor. Luckily it's not surface mounted, so is relatively easy to replace with a 200 ma fuse -- digikey#RXEF020-ND.  Now 35 cents and ten minutes work later, all is well.  I do use a powered USB hub so as not to overload the BB power regulator -- the reason, is suppose, why the designers used the fuse.  

[Gerald Coley]

It is not a fuse. It is a PTC. That is why on the Wiki we recommend an externally powered converter. The 5V comes from the power supply in the wall, so there is no regulator on the board to overload.

We decided to meet the HDMI specification, so that is the reason for the current limit.

 Gerald

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[Gerald Carpenter]

Thanks for noticing my post.

I wasn't suggesting that the BeagleBone design needs to be changed.  I shared my experience to show that the Beaglebone design allows for a semi-competent hardware hacker to make nuance changes to solve a particular problem if one is willing to risk a modest investment.  Isn't solving problems part of the fun? 

I have experienced no problems since I changed the polymeric positive temperature coefficient device (PPTC, commonly known as a resettable fuse).  It doesn't look kluged or hacked.  All internally measured voltages and temperatures remain nominal.

My old VGA monitor has a new purpose  

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[Gerald Coley]

Oh, I totally understand where you are coming from. The only issue I have is that not everyone is you or me.Yes, it can be easily done.  

Other people notice these posts as well and I need to make sure there is a level set for those that try to do the same thing, blow up a board and then send it in to our RMA shop for us to fix.

Everyone is free to do whatever they like to their board. But there are certain things they need to understand before doing so.

Gerald