iRobot Roomba 5xx schematics wanted

[madan1]

Hi everyone.

Has anyone seen proper schematics for Roomba 5 series ( 530 )?
I just got a faulty one. The problem is that it reads one of the bumper sensors constantly as "ON" while the sensor works fine.
Unfortunately the board is totally user un-friendly and it will be kind of mission impossible to troubleshoot it without the schematics .
Here are some photos:

[sam_sam_sam]

Re: iRobot Roomba 5xx schematics wanted

Hi everyone.

Has anyone seen proper schematics for Roomba 5 series ( 530 )?
I just got a faulty one. The problem is that it reads one of the bumper sensors constantly as "ON" while the sensor works fine.
Unfortunately the board is totally user un-friendly and it will be kind of mission impossible to troubleshoot it without the schematics .

Not necessarily the case

Here are some photos:

Dose it have an optic sensor IC chip that hook to the bumper sensor
If not then there might be a resistor that pull it high or pull it low make sure that this resistor is not shorted or has very low resistance

How most of these inputs work is either it is 5 volts or 0 volts that tells the controller that it needs to do something

Check it against the side that works

Post a photo of where the bumper wires hook to the board

[madan1]

Re: iRobot Roomba 5xx schematics wanted

Thanks for the reply.
The sensors consist of IR LED and light detector. The IR LEDs are connected in series to PIN 1 and 2 on the connector.
The Left lihgt detector is connected directly to pins 3 and 4, the right - pins 5 and 6.
Here are some Voltages measured in reference to the board's common ground.
PIN ( light detector NOT obstructed - OFF / light detector obstructed - ON )
1 - 3.6 / 3.6
2 - 1.3 / 1.3
LEFT
3 - 0.09 / 4.82
4 - 0.01 / 0.01
RIGHT
5 - 0.11 / 4.7
6 - 0.02 / 0.01

I was able to trace the paths to the following resistors and see the same voltage behavior when the sensors are triggered:
Left sensor - R86 and R87
Right sensor - R82 and R83

[madan1]

Re: iRobot Roomba 5xx schematics wanted

update - today the roomba decided to work.. at least for some time. Several times it worked fine for about 30-60 seconds before the sensor failed again.
In BIT mode, the sensor also is detected properly for some time and then it again goes in constant ON mode.


update 2 - Just found the following diagram in a russian website

[madan1]

Re: iRobot Roomba 5xx schematics wanted

Update:

Thanks to the above scheme, I was able to "locate" the problem in the trace between C189 and R86.
I really doubt that I would have the nerves to trace the path for the whole ~15cm and the XX passes from side to side.
It is really a shame that otherwise good and perfectly working equipment dies and gets dumped for such small issues, which are easily fixed if the proper schematics are available!

[madan1]

Re: iRobot Roomba 5xx schematics wanted

And to finish the topic for me.

I wired C189 to R86 and did full manual BIT and several full clean, dock, spot cycles without any issues noticed. The robot works as good as new at least sensor-wise ( there is a suspicious noise probably coming from one of the wheel motors, but it is not a matter of this topic or forum ).

And to make the topic useful for other iRobot roomba 5xx 500 530 560 6xx 600 690 and probably for 700 800 900 series I'm including the following information:

The website where I got the diagram that solved the problem for me is http://ixbt.photo/?id=album:56510

I'm also uploading copies of the diagrams form the above link ( for backup purposes ).

[sam_sam_sam]

Re: iRobot Roomba 5xx schematics wanted

I am glad that you figured out what the problem was with your machine
Thanks for sharing your results and the schematic diagram for this product

What did you do exactly to fix your problem with this machine
Was it a bad soldering joints or something else

[madan1]

Re: iRobot Roomba 5xx schematics wanted

I fixed the problem by soldering a wire from R86 to C189.
Here https://www.badcaps.net/forum/attach...1&d=1587352824 you can see R86 next to the 4 transistors ( only the legs visible ) on the upper-right side of the photo.
C189 is right ( 1 o'clock ) to the crystal on the same photo.
First I noticed that the resistance in the left and right sensor circuits b/n R83/86 and C190/189 is different. The right was showing values close to 0 ( cheap multimeter, so can not be truly trusted ), the left one ( the problematic ) was all over the place. Then I noticed that the value changes when the board is pushen/flexed. That lead me to believe that the problem was cause by a faulty trace bridge(?) between the upper and lower PCB sides ( looks like the trace goes at least several times from side to side, so I did not even try to find where exactly it failed ).
The board looks nice and pretty with that white paint, but my personal opinion is that it is not very good quality. I would not be surprised if there is a significant percentage of units reaching the dumpster due to similar issues.

By the way, I recently dissembled the main brush gearbox and its motor reductor. In some occasions it was sounding like some of the gears were grounded, but to my surprise, all gears ( all plastic ) are absolutely fine. There is only a small play in the reductor axle ( unfortunately it is in a sleeve, not bearing ), which considering the units 10+years age is more than good.

[sam_sam_sam]

Re: iRobot Roomba 5xx schematics wanted

That what I though it was the way you were talking about it that it was bad joint or a bad trace

I have seen this a few times before on this type of boards

“The board looks nice and pretty with that white paint, but my personal opinion is that it is not very good quality.”

I would not either

“ I would not be surprised if there is a significant percentage of units reaching the dumpster due to similar issues.”

[madan1]

Re: iRobot Roomba 5xx schematics wanted

And another great example of the roomba mainboard quality...

Symptom - from time to time indicates "charging error 3" when docked or plugged in. In the only available service manual, the error is explained as "Charging FET Failed. The error occurs when the FET test fails at the beginning of the charge cycle."

Some background - when the unit arrived, there was heavy crystallization on the battery electrodes, spreading to the contact plates. From the beginning it was giving the error message, but I thought it was the bad battery and contact plates. Even with two other batteries, cleaned and covered with solder contact plates, the unit was still occasionally throwing the error. To recover from the error, it was needed to disconnect the battery ( which includes some disassembly ).
Since the unit is intended for a friend, it was about time to dig deep and get to the root cause.

So I cleaned the board with some spirit and brush, reheated the FETs joints and now will have to see how the tests will go.
Will also have to figure out with what to cover the exposed paths

[sam_sam_sam]

Re: iRobot Roomba 5xx schematics wanted

You can use finger nail polish it you are that concern about it but unless you are in a high humidity area and using in this kind of environment then yes you should be concerned about it

Other wise I personally would not worry about it

[lbrmnk]

Re: iRobot Roomba 5xx schematics wanted

Hello madan1,
have you succeeded with the charging error 3 repair?
Can you please advice me, which part did you reheated?
I've just cleaned the board and contacts but still having same chaging 3 error.

Thanks Libor

And another great example of the roomba mainboard quality...

Symptom - from time to time indicates "charging error 3" when docked or plugged in. In the only available service manual, the error is explained as "Charging FET Failed. The error occurs when the FET test fails at the beginning of the charge cycle."

Some background - when the unit arrived, there was heavy crystallization on the battery electrodes, spreading to the contact plates. From the beginning it was giving the error message, but I thought it was the bad battery and contact plates. Even with two other batteries, cleaned and covered with solder contact plates, the unit was still occasionally throwing the error. To recover from the error, it was needed to disconnect the battery ( which includes some disassembly ).
Since the unit is intended for a friend, it was about time to dig deep and get to the root cause.

So I cleaned the board with some spirit and brush, reheated the FETs joints and now will have to see how the tests will go.
Will also have to figure out with what to cover the exposed paths

[madan1]

Re: iRobot Roomba 5xx schematics wanted

Hello madan1,
have you succeeded with the charging error 3 repair?
Can you please advice me, which part did you reheated?
I've just cleaned the board and contacts but still having same chaging 3 error.

Thanks Libor

Hello, sorry for the delay.
Yes, I fixed the charging error by just some good cleaning.
Most likely the problem was caused by shorten traces ( see here, right to J15 - the traces have lost their protective cover and some copper oxidation is visible https://www.badcaps.net/forum/attach...9&d=1596407328 ).
If you still have not fixed your unit and still have it, post some details about the problems that you are experiencing and what troubleshooting you have done.