PCB Power Issue

I

iori3310

New Member
Hello friends.

I am posting here after very long time. Hope you all doing great.

Recently I received some devices known as Cloud Computer. I don't know who the manufacturer is but the concept of cloud computer is great regarding this pcb. Well here are the pictures of the device (outside and inside) -








Now lets go for the problem part. The only main problem with 4 of these devices is that it powers up when I plug in the 6v 1A adapter. But the device doesn't boot up. So, I opened them up and touched the PCB while power on. There is only one component that heats up like hell and becomes untouchable. Here is the picture of it -



Unfortunately, I do not know what this component is and it becomes excessively hot. Note that, I already opened the good ones that boot up and there was no heating issue on any components. Could this component be faulty? Should I replace it? Please provide me with some suggestions. I need these devices working for a computer lab.

Waiting for your kind reply.

Iori
 
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Make sure the voltage applied matches the label on the box. It seems like the glass Zener is working too hard. But the Green LED is a good sign.
 
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iori3310 said:
The only main problem with 4 of these devices is that it powers up when I plug in the 6v 1A adapter.
Click to expand...

The powers supply for those appears to be 5V, not 6V!
(See line 6 of the specs below).

That diode is likely a transient protector & it's trying to hold the voltage down. If the input supply goes directly to any critical 5V devices, it's possible things have already been damaged.

If the "6V" was a typo, someone may have connected a wrong adapter or the wrong polarity adapter in the past and damaged the protection diode.


Specifications, from an old ad I found:

HSIPC ARM Cortex A9 Quad Core 1.6GHz Linux thin client pc station network terminal computer Cloud PC With RAM 1G,FLASH 8G,Wifi Include USB VGA HDMI,RDP8.0,Embedded linux 3.0 OS​

Click to expand...

 
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starLED said:
It's a diode.

Do you have a multimeter to test it?

You can replace it of course, do you know how to solder?
Click to expand...
Thanks for the reply. I have a multimeter but I do not know how to test it. Although I can replace it but I don't know where to search for it. Yes, I can solder.


For The Popcorn said:
Do you have the polarity reversed?
Click to expand...

I don't know how to check that. But the SMD above the zener diode is SS24 and I get negative readings when I attach it with the multimeter. Negative 6v.

Tony Stewart said:
Make sure the voltage applied matches the label on the box. It seems like the glass Zener is working too hard. But the Green LED is a good sign.
Click to expand...

The green LED is a good sign for all the devices because they all have green light up when power adapter is attached. The voltage matches with the label on the box but it seems some components were damaged.



Yes, someone used unspecified adapter to run this component and damaged most of the devices. But here is the twist part. Although it is written 5v 2A on the back label of the device, but it doesn't run with 5v 2A adapters. The devices boot up only when it is attached with 6v 1A. Remeber I said, some of the devices working just fine. But the devices don't boot up with 5v 2A or 5v 1A. I tried many adapters with same output range. I just need to figure out how to replace that zener diode.

Thank you for your suggestions. Looking forward to more solutions.

Regards
Iori
 
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Check the polarity of the adaptors, it's looks likely that the 5V ones you have are the wrong polarity.
 
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starLED said:
Isn't the polarity on the adapters like those always the same?
Click to expand...

No, NO and NO!!

They can be either polarity, it used to be about 50/50, but in more recent years it's tended more towards centre positive.

This is why those universal adaptors, that come with multiple plug-in connectors, can be configured either way.
 
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If the diode gets hot with 5V 2A, remove it and try again. If not, it's supposed to be an overvoltage protector and get hot so 6V is wrong.

As I recall, the older ones were centre-negative, trying to be difficult and single-sourced and really old ones were AC in which case polarity is moot. I see this board has dual rectifier power diodes and four DCDC converters nearby and one in the corner. Show the label with power info.
 
Last edited:
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Well, I was in delusion.

I used couple of universal adapters, luckily they were fine, so no damage was inflicted to the device, but in the future I will be careful.

Thanks for the enlightenment.
 
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Hello.

You can see above that I replaced the zener diode. But whenever I plug in the adapter the SS24 SMD above the zener shows reading negative -6.01 V. But this time the zener diode does not get hot. I am not sure now what could cause the problem. Please help me out here.


Reagrds
Iori
 
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