Hi guys i have problem with motherboard of toy car kids , when i plug 12v to the board i notice that the ic Mx3212b is heat quickly, when i test the vcc of ic i read 12v on dmm !!
The Mx3212b is motor drive ic it need only 3v or 5v maximum .
And the second problem is short circuit on the motor connector on the board .


Can any one help me to solve the problem please

 

CERTAINLY a short circuit can lead to overheating. So the very first step is to fix the short circuit problem. Usually that is either an incorrect connection or a damaged wire or a failed component.
What have you done so far?? Please let us know.

 

Certainly a shorted connection can cause serious damage to any electronic component that will experience excessive current.

 

Certainly a shorted connection cab cause serious damage to anyelectronic component that will experience excessive current.

Dear can u give me your whatsapp number please

 

I do not, as far as I know, have such a "whatsapp" number.
WHAT is the intended battery voltage supply to this board??
From the very limited information it is not possible to suggest what will solve the problem. In addition, I am unable to know what is not described about the rest of the system.

 

The supply is 12V do u think that the problem will solved by changing the MX3212B IC??

 

Quite often a failed IC is the result of some other portion of a system having some problem, or a fault. The device marked as "U3" may have been damaged by the shorted circuit, and it may be related to the overheating of the U8 IC.

So let us know what that U3 device actually is, please.

 

Quite often a failed IC is the result of some other portion of a system having some problem, or a fault. The device marked as "U3" may have been damaged by the shorted circuit, and it may be related to the overheating of the U8 IC.

So let us know what that U3 device actually is, please.

U3 is mosfet 150n03 i change it with irf1404

 

Also The short circuit is in relay place in the board i

 

I forget to tell u that the voltage regulator 7530m (3v regulator) has a 12v in input and output

 

Welcome to AAC.

Can you give us a picture of the other side? I suspect what you're seeing as a short is just a closed relay. That may be totally normal for the operation of the board. Also:

when i plug 12v to the board i notice that the ic Mx3212b is heat quickly. • • • The Mx3212b is motor drive ic it need only 3v or 5v maximum .

If the IC needs only 3V or 5V and you're pushing 12V into it - Yeah, that's going to overheat it. We need to see how and where you're introducing the 12V to fully understand how and why it's experiencing problems.

Quite often a failed IC is the result of some other portion of a system having some problem, or a fault.

And I second that sentiment. Often a problem that has been manifested is the result of a failure elsewhere. A shorted transistor or cap can lead to a cascading failure where one component fails and in its failure it damages another part or parts of a circuit. The old adage is to always fully diagnose a problem before you start fixing it. Changing a FET with one that doesn't match can also become another issue. I'd have to look at the data sheets for both components and compare whether the new one is same or better than the one you replaced. But that leads me to another question: Why did you replace the FET in the first place?

U3 is mosfet 150n03 i change it with irf1404

Did you compare the specs of the two devices?

 

OK, how did you change this:



with this:

 

Are you saying your 3V regulator is putting out 12V in these places?

If so - you have a shorted regulator. And likely a lot of other failed components.

 

OK, how did you change this:

View attachment 369648

with this:

View attachment 369649

Certainly changing a single device for another single device with an entirely different package can be done. And just as certainly it requires changes that are possibly quite extreme, in the connection arangement. Always, it requires knowing the actual connections arrangement of both devices, annd usually it also requires some creativity, and compromise.

 

U3 is mosfet 150n03 i change it with irf1404

Looking more closely, U3 is the stated component he changed. 150N03 is what he called it but obviously it couldn't have been. I think he misquoted his components.

 

Since I AM ONLY ABLE tp perceive what folks post, but not what is in their heads, some times interpreting posts gets a bit confusing for me.