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Anndroid box (Mx box 3) won t turn on

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mista1

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Hi Guys i have a problem with mx box 3 won t turn on
And no more standby led light i test ac plug 12v ok any idea?
I will post a picture of pcb i try to measure voltage input on the connector plug on thé pcb no voltage
I dont know if i measure on thé right pin on thé pcb

MX BOX 3 BACK.jpg

MX BOX 3 FRONT.jpg

MX BOX 3 FRONT.jpg
 

Hi any about testing smd capacitor for short?
Thanx
 

Hello mista1,

i try to measure voltage input on the connector plug on thé pcb no voltage

Could you please take a close up picture of the 12V power connector of the MX Box.
Both sides of the connector and some surrounding components would be good.
Regards,
Relayer
 

Hi friend thanx à lot for help i Will do a picture of that thanx
 

hi this is the picture of front connector plug
20180430_181046.jpg 20180430_181046.jpg

and the back side (the connector has 5 pins )
20180430_181204.jpg
 

Hello mista1,
Could you please have a look at the picture below:

Mx Box 3

The arrows marked in RED, could you please check them
for continuity. They should read almost zero ohms.

Same goes for the ones marked in GREEN, these are ferrite
beads. These should also have very low ohms readings.

The ones indicated with BLUE, did you remove either or
both of those electrolytic capacitors?

By the way, its very rare for capacitors (the light tan colored ones) to ever go
short circuit.

Please let us know how you get on.
Regards,
Relayer
 
Last edited:

Hi friend thanx a lot for your response about the blue one i never desolder something there it was original (normally which ic can we add?)

About continuity test do i need to test each side of resistance (red probe) and connector plug (black probe on front or back side (5pins) ?)

Thanx for help
 

Hello mista1,

Hi friend thanx a lot for your response

You're welcome. :wink:

normally which ic can we add?

Sorry, but I don't understand. What IC?

About continuity test do i need to test each side of resistance (red probe) and connector plug (black probe on front or back side (5pins)

You need to check continuity of the resistors and ferrite beads across the component themselves.
It doesn't matter which way your probes are set, as those components I marked are not polarized.
See the two pictures below:

Picture A

Picture B

As you can see, it doesn't matter which probe goes to which ends of the component. It should give you the same readings.
Please don't go by the value indicated on the pictures of the multi-meter, as the readings will be different when you measure
with your meter and the value you get will be dependent on the accuracy of your own meter.
But as long as you read very low ohms, then the component/s should be OK.
If you do get a, "OL" or "OC" indication on your meter, then the part is likely to be open circuit.
If you don't have an auto-ranging meter, then set it to its lowest ohms range. eg. 200 ohms or lower.

Please let us know how you get on.
Regards,
Relayer
 

hi The arrows marked in RED and green the resistor are 0 ohm

about the ones in blue it s was empty

regards
 

Hello mista1,
Could you please refer to the two pictures below:

TOP

BOTTOM

Referring to the "TOP" picture, could you please very carefully inspect the area shaded in
GREEN, as it almost looks to me that it has been overheated.
It also does look like glue or solder of some sort, but it really looks partially melted.

In the "BOTTOM" picture, could you please plug in your power source that came with your
Mx Box. Turn the power supply on, and measure those points shown by the red/black arrows
for voltage measurements.
As you can see I've colored them for polarity for you, so you'll know how to place your probes.
Set your multi-meter to read DC voltage. If you don't have an auto-ranging one, then set it to
read 20 volts DC.

Please let us know how you get on.
Regards,
Relayer
 

hi friend sorry i was too busy with my work ...

so i take some measurement has you say to me you can see on the picture some measurement test.

about the melted plug it s was my fault because i try to desolder smd ceramic cap (red on the picture) to try to test it with hot air solder (not good idea )






GtboHS0.jpg1.jpg


thanx for help
 

Hello mista1,

hi friend sorry i was too busy with my work ...

No problem, I can understand. :wink:

Can you please refer to the picture below:

Image 1

I need you to perform another voltage check, on the ones indicated by the arrows.
We need to determine if there's a problem with your power connector on the PCB
or whether the fault is in the connector itself, or its a fault within the circuit.

Please check next picture:

Image 2

In the above, I need you to trace from the power input pins on the solder side of
the PCB to the points marked by the red arrows on the component side. You need
to see which component/s are physically joined to each one on the connector.

Please let us know how you get on.
Regards,
Relayer
 
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    mista1

    Points: 2
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Hi friend thanx à lot for help about thé second part of your message can i do that with bip test?

Thanx for help
 

Hello mista1,

Hi friend thanx à lot for help about thé second part of your message can i do that with bip test?

Yes, as it should show continuity. But not when doing the voltage test.

Regards,
Relayer
 
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Reactions: mista1

    mista1

    Points: 2
    Helpful Answer Positive Rating
hi friend i follow my study about voltage test and continuity test

i post all information on the pictures

thanx a lotw.jpgx.jpg
 

Hello mista1,
My apologies for not getting back to you much sooner... I've been busy with other projects
non-electronics related. :-(
Anyway, what we need to do now is to isolate your power supply to determine if its the PSU
or the main board that's causing the voltage fluctuations.
Looking at the picture below:

Picture 1

What I need you to do is to associate Pin2 and Pin3 with the picture shown below:

Picture 2

You need to find out what component/s 1, 2 3 and 4 are connected to Pins 2 and/or 3 that's
shown below the main board (Bottom).
If, lets say for example, that one of the inductors and one of those resistors are connected
to Pin 2, then you need to remove one of those components, but that's if one inductor is in
series with one of the resistors. But if they are in parallel, then we need to move along to
the next component/s that are in series.
As I've said above, we need to isolate your PSU from the main board.
Are you able to measure the plug end on your power supply end, or is it too small for you to
insert your probes into it?

Please let us know how you get on.
Regards,
Relayer
 

hi friend thanx a lot for you help and for your time first and i understand that you are busy ;) it s not a problem about the test of the end of plug i can measure it without problem
when i test it i have 12.26v at the end of the plug and test an other plug to be sure on this android box and same problem not starting and no stby light

i follow my study about my bip test i post the result with pictures thanx a lota.jpgx.jpg
 

Hello mista1,
What we need to do is follow the course of your main voltage rails into the rest of the
circuitry on the main board, which is going to get a bit complicated and perhaps frustrating.
What makes it harder is that you have no circuit designations on the main PCB to identify
each component number. :sad:
But before we get into it; I find it very strange that your power supply outputs 12.26 volts,
yet the electrolytic capacitors near the power connector are only rated for 6.3 volts. :???:
For this factor alone, I guess we can't completely rule out your PSU. Though it is ouputing
something at least, but 12.26 volts seems a bit too high.
Another point is that the Ricoh RN5T618M IC is rated with a maximum input voltage at
Vsys1 (Pin12) = 7.0 volts and at Vsys2 (Pin13) = 6.0 volts. Typical volts should be for both
inputs is 3.6 volts.
Can you please have a good look at the power supply to see what its output is supposed to
be? It should be printed on the same side as the mains pins.
I did a Google search on your device and according to most info I got, the power adapter
is supposed to output 5 volts @ 2Amps.
I might get you to check that before getting into the complicated stuff...
Regards,
Relayer
 

hi friend thanx a lot for your help first i test for you again the voltage output and it s 12.26v (pictures 1 and 2) i post too some information of the ac plug output voltage that i use for mx box (picture 3) i test too with othe ac plug with 5v output but i don t know if it s enough to start the mx box but nothing happen (picture 4).

i forgot to add a small information on the mx box android there is a switch button with a led light connected to the mainboard i post the picture too maybe it can help? (picture 5) thanx again for your help and your time


20180614_092611.jpg20180614_092625.jpg20180614_092413.jpg20180614_092432.jpg20180614_092526.jpg
 

Hello mista1,
I deeply fear that your M3 Box maybe beyond repair, due to you applying 12 volts to it. :sad:
The Ricoh (RN5T618M) marked IC does the DC to DC voltage conversion and regulation; converting
5 volts to 3.6 volts for the rest of the circuitry. Its maximum voltage input is 7 volts, but you exceeded
this by 5 volts.
I'm assuming that the original power supply you used was the 5 volt unit, but due to the Box no longer
working, you tried the 12 volt PSU in hopes that it was just the power supply (i.e. 5 volt unit) was the
cause of your Box's problem?
I doubt the unit has any over voltage protection on its input and this is why you were getting an unstable
voltage when you plugged the 12 volt supply in.

Could you please look at the picture below:

Continuity Check

What I need to get you to do is do a beep test between the green and red arrows. I want to see if this
transistor is the one that switches the input voltage into the rest of the PCB. If it does, then there should
be continuity to either the Emitter or Collector of the device.

We can continue to trouble-shoot this, but since you may have two different faults, (your original one,
and now the over-voltage one), it may be impossible to repair it. We would firstly need to assess what
part/s may have been damaged with over-voltage, but the only way of being certain, is to replace the
faulty ones. For one, you would need to replace the IC I mentioned above. But unfortunately a new one
doesn't come in the same package as your original. I don't think there would even be an adapter socket
to suit. Even if we were able to replace that IC, we still have the problem of seeing if anything else has
also been damaged, in addition, we need to find your original fault.
I really think you need to bite the bullet and write the unit off.
Sorry that I can't give you better news, but if we try to continue, it would be like flogging a dead horse.
Regards,
Relayer
 

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