belial
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Red is off, green is on, pi is very hot

Sun Jan 04, 2015 8:01 am

Hi to all!
A have a very strange problem with my Pi B+. It worked fine, but one day i decided to play with Gpio's. I wanted to plug in the old computer Hdd Ide (ata) cable, to connect Pi to the breadboard. But when i plugged it, pi shutted down.
After unplugging I have red led permanently off, green led permanently on. And board is abnormally very-very hot near CPU.

What happened? Is this the end for my board?

drgeoff
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 10:16 am

Your board is probably dead especially if the ribbon cable was an 80 conductor one.

belial
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 10:58 am

But why did it happened?
In my opinion, i only made all pins "longer" by the connecting cable...

DirkS
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 11:07 am

belial wrote:But why did it happened?
In my opinion, i only made all pins "longer" by the connecting cable...
If it is an 80 wire ribbon cable there are probably cross-connections between the pins and your Pi gets fried.
You can only use the 40 wire ribbon cable with the Pi.

Gr.
Dirk.

belial
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 11:31 am

Thanks for replies!
Cable is really 80 wires. I was so silly, that i did not count wires. I could not suppose 40pin connector had 80 wires that are crossed each other :oops:
Good experience for me, I shoul be more carefully.

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DougieLawson
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 12:28 pm

DirkS wrote:
belial wrote:But why did it happened?
In my opinion, i only made all pins "longer" by the connecting cable...
If it is an 80 wire ribbon cable there are probably cross-connections between the pins and your Pi gets fried.
You can only use the 40 wire ribbon cable with the Pi.

Gr.
Dirk.
How can you tell?

What external markings warn you that it's a "fry your pi" cable?
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pwinwood
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 12:48 pm

DougieLawson wrote: What external markings warn you that it's a "fry your pi" cable?
Don't assume that any old cable is suitable.

To adapt the old adage:

Measure (with a continuity tester) twice, plug in once ;)

Specifically pin 34 on the connector is grounded on the motherboard (blue) end of the cable.

fruitoftheloom
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 12:52 pm

DougieLawson wrote:
DirkS wrote:
belial wrote:But why did it happened?
In my opinion, i only made all pins "longer" by the connecting cable...
If it is an 80 wire ribbon cable there are probably cross-connections between the pins and your Pi gets fried.
You can only use the 40 wire ribbon cable with the Pi.

Gr.
Dirk.
How can you tell?

What external markings warn you that it's a "fry your pi" cable?

80 pin Cables should be sold as ATA66 / 100 / 133 ;)
Retired disgracefully.....

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DougieLawson
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 1:41 pm

pwinwood wrote:
DougieLawson wrote: What external markings warn you that it's a "fry your pi" cable?
Specifically pin 34 on the connector is grounded on the motherboard (blue) end of the cable.
Assume I'm from the planet Zogg and a kind human has just given me a RPi (to show how advanced the Human race has got). I've never seen a motherboard, an ATA disk or one wired to another but there's a random cable in a box of bits that came from the charity shop. [Note: In real life I honestly have never moved on from plain old IDE drives.]

Now explain how to identify the cable.

The reason behind this is to stop the new users from killing their equipment. We can get Mahjong to add a line item to the "pitfalls" sticky thread if we can develop a simple explanation.
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pwinwood
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 3:13 pm

[quote="DougieLawson]Now explain how to identify the cable.[/quote]

An 80 pin IDE cable should has a blue connector on end and a black connector on the other. It may also have a grey connector in the middle. However as they are mass-produced where price is everything, it is not guaranteed that these conventions are followed. In addition a surplus cable may have been roughly handled causing pins to have become disconnected from the wires in the cable. The simple explanation is to only use a cable specifically designed / purchased for the job or you test the cable with a continuity tester to check before using it.

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mahjongg
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 3:23 pm

simply count the wires, 40 is okay, 80 will fry your PI!

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rpdom
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 3:32 pm

Often the 80 conductor ones will have a blue connector on at least one end. Some of the 40 conductor ones will as well, but the ones with just grey connectors are pretty safe.

Also if you look at the cables themselves, the 40 conductor ones are fairly chunky and the individual cables are reasonably easy to count. The 80 conductor ones are very fine and if you can see well enough to count them you might as well do it.

Count just 10 wires from one end. If you are about a quarter of the way across the cable it is a good one. If you barely seem to have started... throw it back ;)

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pluggy
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Re: Red is off, green is on, pi is very hot

Sun Jan 04, 2015 3:37 pm

If its been manufactured in the past 15 years for ATA hard drive use, its almost certainly an 80 way cable. ATA has been practically defunct for 10 years anyway.

If you're pulling one out of an old computer with a floppy drive, a 40 way cable looks like a wider version of the floppy cable without the twists. An 80 way has much finer conductors.
Don't judge Linux by the Pi.......
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