External Hard Drive Bridgeboard

Thread Starter

billycar

Joined Dec 10, 2018
47
Looking to learn about circuit boards so I can test components, debug and repair this one:

The board LED and Hard drive doesn't power on. The hard drive is working in another enclosure. The 12V power supply is good. Power seems to be getting into the receptacle, but maybe not further?

Would like recommendations for basic soldering equipment that would get me started.
Also, a good lamp / magnifier: what magnification power(s) are best, LED? color light options? Not terribly expensive.
Suggestions for a board holding stand.
(Other project uses: Also need to use the magnifier to do detail work on repairing a few torn artist paintings, thread by thread, so the way it mounts and stands is a concern)

I have an Extech MiniTec 24 that has various settings to test circuits and other electronics.

Suggestions welcomed.
Thankyou.
OWCMercuryEliteClassic.jpg OWCMercuryEliteClassicBridgeBoard.jpg
 

MrChips

Joined Oct 2, 2009
22,917
Welcome to AAC!

Looks like a 12VDC to 5VDC buck converter behind the 12V power jack.
I would start looking for 5VDC output.
 

Thread Starter

billycar

Joined Dec 10, 2018
47
Testing Power In (12V) and Power to HDD Plug (both 5V and 12V measure 0)
Correct interpretation of Yellow/Black/Red?
So no power through board to the plug.
Solder point of the Receptacle? Other?

I tested continuity of Switch in the ON (—) and OFF (O) positions.

Also continuity of the little black box (buck converter?) to right of Receptacle. (JP3)

TestPowerHDD_IMG_20181211_101153540.jpg TestPowerHDD_IMG_20181211_100956251.jpg
 
Last edited:

MrChips

Joined Oct 2, 2009
22,917
Two tests to perform.

With the power disconnected from the power jack, wait for 1 minute for the charge to dissipate.
Turn the power switch ON with no power connected.
Measure for continuity between the input power pin and all YELLOW wires.
Measure for continuity between the input power pin and pin-1 of U8.

TO-263 pins are numbered 1 to 5, left to right.



U8 is a Sanken SI-8050JD 5V buck converter.
Apply power.
Measure the voltage between GND and U8 pin-1.
Measure the voltage between GND and U8 pin-5.

The BLACK cable is GND.
Any of the four mounting holes in the corners of the board is also GND.
 

Thread Starter

billycar

Joined Dec 10, 2018
47
I don't seem to be getting any continuity ... no Alarm, for any of the measurements.

Also no voltage measured from Ground to Post 1 and 5.
 

Thread Starter

billycar

Joined Dec 10, 2018
47
I did notice this - Testing Continuity
When I connect a probe to each end, although not an Alarm, I get a flash numeric value or steady value depending on which wire color I am testing to:

Probe Wire Display
Red Yellow HDD steady 616
Black Center pole

Red Red HDD flashes 800-1500
Black Center pole

Black Red HDD steady 1685
Red Center Pole

Black Yellow HDD flashes 1000-1600
Red Center Pole
 

MrChips

Joined Oct 2, 2009
22,917
Post two more photos, top and bottom side, of close-up around the input power jack,
with the ON/OFF switch unplugged, just that corner of the board, including JP2.
Make sure the photos are clear and well focused.
 

MrChips

Joined Oct 2, 2009
22,917
Set the voltmeter to measure 200VDC
Apply power and measure the voltages at the pins of the two connectors shown.
Do not connect the POWER SWITCH.

Connect the BLACK test lead to ground around one of the mounting holes.
Use the RED lead and test all the pins of the connectors, being careful not to short any two pins at the same time.
Number the pins from left to right as oriented in this photo, i.e. the fist pin on the left is pin-1.

The upper connector has pins 1, 2, 3.

The lower connector has pins 1, 2, 3, 4.

ReceptacleDetailBack_MG_0221_test01.jpg
 

LesJones

Joined Jan 8, 2017
2,972
Is it possible that the power to the drive from the 12 volt socket is only enabled when the 5 volts from the uUSB connector is presesnt. (Or it might even need to see some signals on the USB.)

Les.
 

MrChips

Joined Oct 2, 2009
22,917
Disconnect the 12VDC power jack.

Examine the board visually and with the aid of a continuity tester (the diode test on your DMM).

Try and trace how the 12VDC gets to the 4-pin connector.
Pin-3 ought to have a direct connection to the 12VDC input jack. There should be a trace on the component side (top side) of the board.
 
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