# External Hard Drive troubleshooting

#### Etienne_Pelletier

Joined Apr 19, 2020
7
Hi there. I've recently modified an internal hhd from an old computer to use it as an external hhd. To do so I bought a SATA to USB convertor, but when I received it, I found out that it needed a 12V 2A power supply. I don't have such power supply, so I decided to take my bench power supply to power it (I know). And to my suprise it worked, but today I made a mistake and shoot 16V into the adapter... I think the hhd turned into protection mode because the voltage dropped quickly after. When I try to power the hhd (with the correct voltage), the voltage drops again... Does anyone knows the problem and how to fix it?

#### Bobes

Joined Mar 19, 2020
51
It might gone short circuit, computer power supply has protection against short circuit to prevent fire or explosion.

#### DickCappels

Joined Aug 21, 2008
7,147
It is not a protection mode, it is in a dead mode.

A long time ago I bought my own microprocessor and built it int a primitive microcomputer. I was powered by my adjustable bench-top power supply. I accidentally hit the voltage adjustment knob and later I found that one bit in the address bus was stuck in one state. That really limited the size of possible programs. I had to wait weeks until I saved up enough money to buy another (MOS6502). After that, I always included some kind of voltage limiting on projects after that. Typically, the first thing the power input to any board is a 78M05, and later 3.3V versions

Change the chip and don't use it until you put some over-voltage protection circuit in place.

#### AlbertHall

Joined Jun 4, 2014
11,098
Recently I was going to use a switchable wall wart to power a PIC & HC12 board. As it happened the supply was set to 7.5V. When I connected it to the board it didn't work but there was no smoke. After investigation I discovered my mistake and set the supply correctly and both the HC12 and the PIC were undamaged. I don't know how that is possible.

#### DickCappels

Joined Aug 21, 2008
7,147
My point is to protect the expensive parts of the project against operator errors. On another project I switched off the bench-top power supplies in the wrong sequence while on a consulting job. It cost me US $3,000. Another reason I am more careful these days. #### bertus Joined Apr 5, 2008 21,237 Hello, Could it be that some decoupling capacitor created a short? I have had some tantalium capacitors that created the short on the powersupply. Bertus Thread Starter #### Etienne_Pelletier Joined Apr 19, 2020 7 I'll be more careful for sure. What type of voltage protection do you use? Thread Starter #### Etienne_Pelletier Joined Apr 19, 2020 7 How can I verify that. I've just tested some motors and the power supply seem to work just fine... Thread Starter #### Etienne_Pelletier Joined Apr 19, 2020 7 My point is to protect the expensive parts of the project against operator errors. On another project I switched off the bench-top power supply in the wrong sequence while on a consulting job. It cost me US$3,000. Another reason I am more careful these days.
I'll be more careful for sure. What type of voltage protection do you use?

#### Etienne_Pelletier

Joined Apr 19, 2020
7
Hello,

Could it be that some decoupling capacitor created a short?
I have had some tantalium capacitors that created the short on the powersupply.

Bertus
How can I verify that. I've just tested some motors and the power supply seem to work just fine...

#### bertus

Joined Apr 5, 2008
21,237
Hello,

Then the fault must be on the converter board.
Connect the converter board without the HDD (on the correct voltage).
When the short is still occuring, you know the fault is on that board.

Bertus

#### Etienne_Pelletier

Joined Apr 19, 2020
7
Hello,

Then the fault must be on the converter board.
Connect the converter board without the HDD (on the correct voltage).
When the short is still occuring, you know the fault is on that board.

Bertus
I just did and you're right the voltage drops. It sucks but that drive still didn't cost me anything. Thanks by the way.

#### DickCappels

Joined Aug 21, 2008
7,147
I'll be more careful for sure. What type of voltage protection do you use?
Predominantly voltage regulators between the input and the rest of the circuity. In circuits without an on-board regulator Zener diodes are sometimes used.

How can I verify that. I've just tested some motors and the power supply seem to work just fine...
The best test is to remove the suspected capacitor from the power supply. It the short remains, that wasn't the problem. If the short is gone either the capacitor is shorted (confirm with an ohmmeter) or the soldering operation cleared the short.