Hello,
Ive got a maple mini about a month ago and everything was working fine. The only source of power i was applying to it was trough the USB. Today iv tryed to power it with a external battery and iv putted to the Vin 11.7V. I saw some smoke and i immediately cut the power. My question is why that happend?? In the maple mini page says that you can feed the Vin with max 12V! Also did i bricked the chip or just the voltage regulators?Anyway to check this?
fried maple mini?!
(13 posts) (4 voices)-
lucky13
MemberPosted 3 years ago # -
lucky13
MemberOne more thing.. i found that one MCP1703 was burned! Im putting 5V at the input and getting 0.9V at the output while in the other i give 5V in the input and get 3.3V at the output. I can find and replace the burned MCP1703 but the thing that makes me wondering if its only this, is that i hear the buzzer from the multimeter if check the VCC and GND in the "diode" setting.
Posted 3 years ago # -
siy
MemberI'd check capacitors, in particular one at supply input - C1, but C2/C2 also very possible candidates. Initially I thought that transistor Q1 might be damaged, but it has 47K resistor in the base, so this is unlikely. And, of course, MCU itself. Disconnect and reset pins are connected to VCC via resistors, but while resistors can protect against excessive current, they can't protect against overvoltage especially taking into account that input resistance of CMOS IC's is quite high (external resistor and input resistance form a voltage divider, but in this case division ratio is too low to protect the pin).
Posted 3 years ago # -
mikep
MemberYou said you're using the diode buzzer on your voltmeter:
1. do you have the "short" in both direction? I.e. reverse the voltmeter cables and see if you still get the buzzer
2. Use the resistor measurement mode on your voltmeter. A real short would show up as close to 0 Ohms.Sometimes it's hard to tell with integrated circuits because there are all these internal protection diodes in the IC, so the diode buzzer might not be 100% accurate.
Last resort: worst case is the CPU is fried anyway, so just apply 3.3V to the CPU with a 100Ohm resistor and your Ampmeter in series .. if there is a short then you should see close to 30mA of current flowing. if it's significantly less than that your CPU might still be ok, and you could lower the resistors to maybe 47Ohm and test again etc.
These are just suggestions how I would approach it based on the info you have given us. I don't think they would hurt anything, but don't hold me to it :)
Posted 3 years ago # -
lucky13
Memberhello mikep thanx for your help.
Ive tryed your suggestions and here are the results..
1)Ive tryed both of them and same thing..
2)If i measure the resistance between VCC and GND i get 1.6 Ohm's.
And last with a 150Ohm resistor (that was the smaller resistor laying around) and ive got 20mA of current. So is that showing that the uC is ok?Another thing..if i try to give 3.3V from an arduino to VCC and connect the GND's the arduino resets which shows that obviously i have a short
(*Note that all the tests have been done without the 2 MPC1703)
Posted 3 years ago # -
mikep
MemberSorry man, 1.6 Ohms is a short.
It doesn't look good to be honest.
Since you have most of the parts already removed from the board I think that leaves pretty much the uC as the culprit...3.3v/150Ohm = 22 mA ... which is pretty much the current you saw -> another indicator that it's a short.
RIP
Posted 3 years ago # -
lucky13
Membervery nice!=/ so now ive got 2 questions..
1) why this thing happend? i just gave 12v in the input..
the only components that i had connected to the board was an itg 3200 and a bma180..
maybe looking at the mpc1730 datasheet this thing makes sense but all i want to say is that this regulator can only work in real life with inputs around 3.3V , which is totally impractical..
2) Im working for a project with a deadline that uses the maple mini and as far as ive searched i cant find it available anywhere. Do you know when it will be in stock again? even at seeedstudio its out of stock nowPosted 3 years ago # -
mikep
Member1) yes, I always thought the voltage regulators on the Maple (and maple Mini) are underpowered. I assume you read this: http://leaflabs.com/docs/hardware/maple-mini.html#maple-mini-power-regulation
So they state you have only 10mA left over if powering at 12V. I assume the itg3200 + bma180 took that and then some, sending the MCP1703 to Nirvana.
Unfortunately it looks like for any shields and peripherals you have to provide your own 3.3V voltage and not use the on-board regulators (this Makes the maple itself useless for use with a number of shields unfortunately).2) I usually would not recommend going the "clone" route, but since you are under a deadline (it would still take 2 weeks to get these):
http://www.ebay.com/itm/STM32F103CB-Core-Board-STM32-Nano-Dev-Board-Arduino-Compatible-/180770771342Good luck.
Posted 3 years ago # -
pra
MemberI have a mini I don't use and haven't used other than to make sure it worked..contact me at PeterRArcher@hotmail.com and I'll get it to you.
Posted 3 years ago #
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