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Rive
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 6:23 pm

Heater wrote:I have had any stuff trashed by any upgrade yet. I was talking about what happened to you.

Although a weird thing happened yesterday when the power supply I was testing that Pi 3 with accidentally got switched to 12v !

Let's just say I had to run out and buy a new Pi 3.

I'll have to try and get a nice picture of the damage. It's quite interesting what happened and unexpected.
Ouch.
DNPNWO

klricks
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 6:42 pm

Noticed that sound over HDMI now works without having to add hdmi_drive=2 to /boot/config.txt
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

JumpZero
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 6:48 pm

Heater wrote:Although a weird thing happened yesterday when the power supply I was testing that Pi 3 with accidentally got switched to 12v .
:lol: Well done.
A few years ago I energized my Pi at 5V on the 3.3V pin by a USB->serial cable. The SD card died but the Pi is still running 24/7. It's the very first Pi (Pi 1 with 256Mb).
But 12V!.. You did it well ;)

Heater
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 7:14 pm

OK here is the story of my gross stupidity and idiotism...with an unexpected twist...

The Pi 3 was complaining that it's supply voltage was dipping low when running xphl, no matter what USB wall wart or power bank I used. Time to hook up bigger supply.

The only thing I had to hand was a big black box from Vanson. It has a slide switch on the side to select 3v, 6v, 9v or 12v output. I remember now the first time I ever saw that thing that it was just an accident waiting to happen...

So I set the thing to 5v, chop a USB cable and hook it up to the Pi 3.

Well of course, it was time for that accident, whilst messing around with this and that the supply switch gets jiggled to 12 volts. Next time I power it up smokes starts billowing out. Quick as I can I turn it off. "Oh dear" is the polite version of what I shouted. Surely everything is dead.

Just out of curiosity, I set the thing back to 5 volts and tried again. Wow, the Pi booted. Everything still worked.

Well, xhpl was now causing the Pi 3 to complain it was getting too hot. Time for a heat sink.

If that is not interesting enough, I took a close look at the board for signs of damage. What's that...the diode D5 is now standing upright on one pad. Clearly it's solder had melted and it had "tombstoned" as they say in the PCB assembly business.

What is D5? Why do we need it? How come everything worked fine without it connected any more?

Otherwise the board looked fine.

If that is not stupid enough, guess what? The next day I managed to make the same mistake again! More smoke. This time the Pi 3 is dead.

gregeric
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 7:18 pm

D5 is the diode which affords protection against over-voltage. See https://www.raspberrypi.org/documentati ... EDUCED.pdf

Looks like it did its job well, for as long as it could.

Edit: having said that, you might have hoped the polyfuse would trip before the zener let go.

Heater
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 7:50 pm

gregeric,

Thanks. So if I had been patient and replaced D5 the Pi 3 may have survived my second, er, experiment as well.

Actually that D5 seems to still be working, as some kind of diode, according to a simple test with a multimeter.

Heater
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 8:01 pm

gregeric,

Do you happen to know how much over voltage D5 can handle safely long term?

My next available power supply is putting out 5.58 volts with no load.

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rpdom
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 8:13 pm

Heater wrote:gregeric,

Do you happen to know how much over voltage D5 can handle safely long term?

My next available power supply is putting out 5.58 volts with no load.
I don't know how much it can cope with, but the idea is it shorts out if the voltage exceeds about 6V and causes the fuse to "blow" to protect the circuit.

Heater
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 8:25 pm

That makes sense to me. It's a kind of "crow bar" circuit.

So, in theory, I could just try it and the worst that would happen is the polyfuse would open.

gregeric
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 8:32 pm

Heater wrote:gregeric,

Do you happen to know how much over voltage D5 can handle safely long term?

My next available power supply is putting out 5.58 volts with no load.
In short, no.

If you look at the datasheet, it's described as a transient voltage suppressor. You would hope that the maximum duration of any transient it could tolerate whilst shorting said to ground would trip the polyfuse.

Your 5.58V unloaded at the PSU isn't a useful metric versus what might be seen delivered with a typical Pi, load upwards of 300mA.

Heater
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 8:52 pm

gregeric,

Yeah. On reflection it rather depends on the PSU.

If it had a high internal resistance, say some little batteries or sloppy regulated supply the the load the Pi presents, and especially the D5 zener, would pull it down to something tolerable.

If it were a "stiff" supply then the D5 zener would be sinking tons of current trying to pull it down to a safe level. The polyfuse, or something would pop.

I'm not about to try it.

Heater
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 9:02 pm

Wait a minute. The schematic shows that D5 is an SMBJ5.0A. That is not a zener it's a transient voltage suppressor.

Isn't that the wrong symbol used on the schematic ?
Last edited by Heater on Sat May 14, 2016 10:03 pm, edited 1 time in total.

klricks
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sat May 14, 2016 9:48 pm

Heater wrote:Wait a minute. The schematic shows that D5 is a SMBJ5.0A. That is not a zener that is a transient voltage suppressor.

Isn't that the wrong symbol used on the schematic ?
They do appear to have used a zener symbol on the 3B schematic.
Note that the SMBJ5.0A is the unidirectional type TVS. The schematic symbols are so similar that I have to look up the part number to distinguish the uni TVS from a zener. The TVS has a bit thicker 'cross bar'.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.

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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sun May 15, 2016 11:44 am

So raspbian now has a feature to edit wifi settings on the boot partition:
If a wpa_supplicant.conf file is placed into the /boot/ directory, this will be moved to the /etc/wpa_supplicant/ directory the next time the system is booted, overwriting the network settings; this allows a Wifi configuration to be preloaded onto a card from a Windows or other machine that can only see the boot partition.
It seems that's for raspbian .img install only - not NOOBS ? (i.e wifi for the OS downloads)
Android app - Raspi Card Imager - download and image SD cards - No PC required !

mikerr
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sun May 15, 2016 11:58 am

So I went ahead and tried it and it's a no-go :(

I was hoping a suitable wpa_supplicant.conf file would enable the noobs (lite) installer to use preconfigured wifi
for the OS image downloads as well as the final raspbian installation.
That in combination with silentinstall would allow a full headless start from noobs lite.
Android app - Raspi Card Imager - download and image SD cards - No PC required !

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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sun May 15, 2016 3:34 pm

mikerr wrote: I was hoping a suitable wpa_supplicant.conf file would enable the noobs (lite) installer to use preconfigured wifi
for the OS image downloads as well as the final raspbian installation.
That in combination with silentinstall would allow a full headless start from noobs lite.
NOOBS documentation says it should work: https://github.com/raspberrypi/noobs/bl ... fi-network

Maybe with the qualifier that it needs to be an 'official' Wifi dongle, or the Pi3 built-in: read in conjunction with https://github.com/raspberrypi/noobs/bl ... i-networks

[I raised this in the Comments on the RPF blog post - the reply wasn't quite clear.]

mikerr
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sun May 15, 2016 4:14 pm

Ah, that's where I saw it although that section has now moved down the page to advanced setup:
Preconfiguring a WiFi network

If you already know your WiFi details, you can preconfigure NOOBS to use it straight away. Put a copy of your wpa_supplicant.conf file on the NOOBS root partition and NOOBS will read it and store it in its settings for all future uses.
https://github.com/raspberrypi/noobs/bl ... tall-an-os)
tried it on a pi3 with my wpa_supplicant.conf on the fat32 partition - no luck
the wpa_supplicant file in installed raspbian was the default, not mine.
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KanyonKris
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sun May 15, 2016 5:22 pm

Please make a command line version of piclone. I am running Raspbian Jesse Lite and would love to use piclone.

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B.Goode
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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Sun May 15, 2016 6:06 pm

KanyonKris wrote:Please make a command line version of piclone. I am running Raspbian Jesse Lite and would love to use piclone.
From https://www.raspberrypi.org/blog/anothe ... /#comments
Simon Long wrote:Have a look at our GitHub repo for piclone – https://github.com/raspberrypi/piclone There is a script in the src directory called backup – this is the original command-line prototype for SD Card Copier. It might need a bit of polishing, but it should be pretty close to what you need.

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Re: 13th May 2016 Changes to the Raspbian Jessie Desktop

Wed Nov 23, 2016 12:05 pm

Gerd wrote:Old and busted: Mathematica shows its splashscreen and then crashes every RPD session. viewtopic.php?f=94&t=131051
New hotness: Mathematica shows its splashscreen in blue and then crashes every RPD session.
The attachment blues.png is no longer available
Something weird going on in XRDP. I will retest this weekend with fresh image, but not today.
For the other reported bug with XRDP (no ldxepanel showing up over XRDP), switching between boot into gui/console in raspi-config and rebooting inbetween solved that one for me.

Apart from this: nice release and thanks for including Geany.
Mathematica is back ( on xrdp session)
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