U12 chip burnt on a Roomba 560 mainboard

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U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » December 5th, 2017, 9:35 am

Hello all ! :)

I just found a Roomba 560 for a cheap price, and I'd like to repair it.
I bought a new battery because there wasn't any, and when I plugged it, the robot started vacuuming but no button active, no led signal, nothing else... And it doesn't stop vacuuming.

So I thought it could be a electronic problem, which was confirmed when I opened it : a chip called "U12" is burnt on the mainboard:
Image

Do you know what chip it is and where I can find it ? (I tried to google it around, but didn't find the info.) I'm a bit used to electronic soldering and I think I could replace it... But as the chip is seriously burnt, I don't know the reference...

Thank you very much ! :)
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby a1robotrepair » December 5th, 2017, 10:38 am

74HC14http://www.robotreviews.com/chat/download/file.php?id=8550
Remove it by cutting the leads very close to the chip and see if the board will respond with battery power.
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » December 5th, 2017, 12:24 pm

a1robotrepair wrote:74HC14http://www.robotreviews.com/chat/download/file.php?id=8550
Remove it by cutting the leads very close to the chip and see if the board will respond with battery power.


Do you mean that I can test the mainboard without the chip on it ? Isn't this chip needed for the board to start ? :?:
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby a1robotrepair » December 5th, 2017, 12:59 pm

I don't think it is used for the PCA to start. I do know that 4 of the 8 inverters are used for the Right Wheel and Front Brush PWM circuit.

U12 is probably pulling down the 5Vreg which can be checked on the solder joints of L1 to GND.
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » December 5th, 2017, 2:48 pm

I just tried removing it from the mainboard...
Well, it doesn't change anything to the problem : the vacuum starts and never stops, and the robot doesn't react.

Plus, the chip was literally soldered by the fire to the PCB, and removing it (even cautiously) from the PCB pulled a part of the contact tracks off it :(
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby a1robotrepair » December 5th, 2017, 3:27 pm

Vacuum runs constantly! Vac circuit fried. Burnt chip fried to board, PWM circuits fried. PCA fried.
New board needed. Read number under chasis after bin is removed. Will let you know which PCA to order.
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » December 6th, 2017, 1:05 pm

Thank you for your help, a1robotrepair.
I'll let you know the chassis number as soon as I go back home.
But if I'm not mistaken, changing the PCA is almost as expensive as buying another second hand robot, isn't it ?
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » December 6th, 2017, 2:33 pm

a1robotrepair wrote:Vacuum runs constantly! Vac circuit fried. Burnt chip fried to board, PWM circuits fried. PCA fried.
New board needed. Read number under chasis after bin is removed. Will let you know which PCA to order.


So the PCB reading is the following:
Code: Select all
iRobot
4104037
REV. C
2007.03.02
R3 MAIN ELECTRONICS PCB


Did I got it right ?
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby a1robotrepair » December 6th, 2017, 3:08 pm

The board markings are too similar between the 530, 560, 560L and 610 to tell the difference. Does it have a small piggy back board on the lower left of the main board? 560 with RF. No piggy back board, 560Light without RF.

The serial number should be on a white sticker on the chassis cover where the bin inserts.
Example: KYN560010808080300001
The 6th number from the right will tell you the firmware revision.
0 to 5 are RF on all 560s I have found.
6 & 7 are light...except 581, 587.
7 and above can use Auto Virtual Walls.

I have a few 560 boards that need checked, Rf and Light.
Message me when you figure out which one you want as either will work.
I do have the 500 series 2012 Osmo to update firmware.
BTW, 530 non RF or 540 RF will work also but no time or schedule buttons.
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » December 7th, 2017, 5:08 am

I didn't see the white sticker in the bin dock :/ Maybe it has been removed by the former owner...
(Anyway, I'll double-check tonight when I'm back from office, now that I know how the serial number spells like.)

But : yes, it does have this small piggy back board on the lower left corner :) So I assume it's a 560 with RF ;)

I have a few 560 boards that need checked, Rf and Light.
Message me when you figure out which one you want as either will work.
I do have the 500 series 2012 Osmo to update firmware.


Wow, that's nice ! :cheers:
If you have a 560 mainboard that would fit my poor broken roomba, I'm very interested ! :D
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby a1robotrepair » December 7th, 2017, 12:20 pm

OK, before buying a circuit board let's check the motors and charger port.
You will want a new 9V battery.
Remove battery from bot and take it apart down to where the circuit board is exposed.
Do not remove modules.
The front brush is easy, apply the battery to the front brush contacts. Reverse battery and check again. Should run forward and reverse.
IMG_1637.JPG

Connect 2 wires to your 9V battery and connect them to pins 1 & 2 of the 3 solder connections both wheels and the CHM. You will need to block your bot off of the surface you're working on while doing this so that they can spin freely.
Again, forward and reverse.
IMG_1638.JPG

You will see where the side charging jack is. Check continuity with ohm meter between circuit board pins corresponding to the black and brown wires
I received your message.
Get back to me when all is checked.

This method is not recommended for a working circuit board.
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » Yesterday, 4:44 pm

Hi a1robotrepair,

I did the tests as well as I could...
The front brush test worked, so does the charging port.

But concerning the pins for the wheels motors, on this point I have to say that I didn't get very clearly the action you showed me.
You mentioned pins 1 & 2, but on your photograph, there are 4 of them that are crossed by the red line... :doh:

So I tried only 2 of the pins you showed, it only moves the front brush. No matter any group of pins I try with the 9v battery... If I try with all the 4 pins you show, nothing seems to happen.
Does it mean both wheels are dead ? Or maybe I simply didn't get your point with their test ? :think:
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby a1robotrepair » Yesterday, 6:36 pm

There are 12 solder points which correspond to 6 connections. The red line represents 2 solder joints on 1 connection.
#1 red line represents connection 1 and #2 red line represents the other. Connect + to #1 and - to #2 then reverse to check both directions, reverse and forward. The solder joints are connected on the circuit board.
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » Yesterday, 8:04 pm

All right, got it ;)

I did the test as you indicated, and each time, on each group of 12 pins, I can hear a motor sound, but the wheels don't turn. Maybe it's the sound of the vacuum motor ?

I did a video, so you can see and hear. Note that even if it appears so, I'm not blocking the robot from moving ;)
https://www.dropbox.com/s/8yjzn9ztg81ki ... 7.mov?dl=0

What do you think ?
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby a1robotrepair » Yesterday, 8:14 pm

I can't believe that board is that shorted out. You should add a picture here of that board. Full editor, add a file, take or choose pic.
Remove modules, the motor contacts are the left 2 contacts of all modules oriented the way they fit into the bot. Be careful not to put 9V on any other contacts.
BTW, that's the bin running.
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Re: U12 chip burnt on a Roomba 560 mainboard

Postby Astrolab3 » Yesterday, 9:19 pm

How do you get the full editor mode ? Can't see that option anywhere on the reply page :)

Anyway, I can give you a Dropbox link again to the board picture :
https://www.dropbox.com/s/w5wmfwm41klmp ... 4.jpg?dl=0

So you mean I should remove the two wheels from the structure and test it with the 9V battery ?
Can you show me a picture of the wheel module contacts that should be alimented with 9V for that test ? Sorry, I'm too afraid of putting it on the wrong ones ><
Thank you very much ;) :thanks:
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