56 replies to this topic

[dog-man]

I just did an over the air update to my vuduo running openpli4 and now the box will boot up properly.

 

It will display the boot up channel but the display on the vuduo stays at restarting or a garbled version of 'reading usb' even though there is no usb to read.

 

The box is unresponsive and all I can do is power down and up with the power switch at the rear of the vuduo.

 

Is it just me?

[Huevos]

My Duo often does that. It has ever since I got it. Nothing to do with any image in particular. Just switch it off and on at the rocker switch normally clears it.

Edited by Huevos, 2 May 2014 - 19:11.

[WanWizard]

Last time I had that a capacitor was about to blow...

[dog-man]

Replaced the capacitor with a higher spec end of last year so unlikely to be that.

 

I have now managed after about 15 power downs and back on again to get it to boot up fully.

 

Panic over for now.

[Erik Slagter]

Then probably this capacitor is going to fault any time soon as well (because you didn't add a ceramic capacitor in parallel, probably) or the voltage regulator itself is dying, because it has been stressed for a long time by a bad capacitor.

[dog-man]

Is there a FAQ about this ceramic capacitor?

I don' recall ever seeing anything about this.
I just replaced one capacitor with a higher value when all I had when powering on was a red light.

dog-man...

[WanWizard]

There's a design problem related to high frequencies that causes the capacitor to deteriorate prematurely.

The ceramic capacitor is there to filter those frequencies, if you don't add it you new elco will go quite quickly as well.

 

You should be able to find plenty here if you search for C807.

[dog-man]

Thanks. I shall investigate.

[Erik Slagter]

BTW replacing the capacitor with a "higher" value won't help. If it's a higher capacity (more uF's) it may not even work and a higher voltage won't help.

[dog-man]

Just checked and 807 is the one I replaced last November.

[dog-man]

Can anyone give me details about the ceramic capacitor?

[Erik Slagter]

It actually not that important exactly what ceramic capacitor to use. Just use whatever you have lying around, anything with a capacitance of 100 nF or bigger, being a ceramic or a plastic C doesn't even matter (MKT, MKC, MKP...). As long as it's no electrolytic C, I wouldn't advice using tantalium as well. It has to do with "high" frequencies detoriating the electrolytic C, the non-elco will short these frequencies.

[dog-man]

I replaced C807 late last year, so which number is the ceramic capacitor I should also change?

[Erik Slagter]

You don't replace the ceramic C, you add it. Make the ceramic C short the elco. In other words, solder the ceramic C to the same points the elco is soldered to. For the elco, watch the polarity, for the ceramic (or plastic) the polarity doesn't matter.

[dog-man]

So I need a ceramic capacitor and I solder it to the C807?

 

Can you give me exact details / specs of a ceramic cap I should get?

 

I can get one either tomorrow or Monday if I have enough time.

[Erik Slagter]

Yes solder it parallel to the C807. Or actually, solder both the elco and the ceramic C to the points where the C807 was soldered originally. I can't explain it more clearly .

 

Like I said above, it's not quite important what value or type to use. As long as it's "solid" (ceramic, plastic). Capacitance about 100 nF or bigger, voltage > 12 V, that's all. It doesn't have to cost more than a few cents.

[dog-man]

OK, Thanks. I will definitely do this when I can get one.

 

I have known about C807 cap failing for many years, but have never known about adding a ceramic cap also.

 

 

 

dog-man....

[Pedro_Newbie]

You could use such as these: http://www.ebay.com/itm/330824144938
But it can take a while before you get them

[dog-man]

Thanks.

I am in the UK, but I am sure that I can source them.

[dog-man]

Order placed so hopefully within 2 weeks it will arrive all the way from China.