Roomba 625 Vacuum motor turns on and off

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Roomba 625 Vacuum motor turns on and off

Postby przemo33 » March 11th, 2015, 3:52 am

Hello,
I have a problem with a motor during operation Bin Vacuum switches on and off for a few minutes (less time and once more).

How to Turn on 17 Built-In-Test is operating normally.

Pin MCU which is responsible for the Init Vacuum Motor?


In addition, you can not perform a reset by the (SPOT + DOCK 10s).
After attempting to perform a reset is not quenched CLEAN and silent melody, and for that he says to clean the brush and never will enable the CLEAN cleaning.
Only after removing and inserting the battery can be switched on again.

Thank you in advance for your help.
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Re: Roomba 625 Vacuum motor turns on and off

Postby Gordon » March 11th, 2015, 12:53 pm

przemo33 wrote:Hello, ...I have a problem with a motor during operation Bin Vacuum switches on and off for a few minutes (less time and once more).
Hello przemo33. It appears to me that all we know at this instant is: Your 635's vacuum fan motor does not remain in operation when it should. The fault can be in the 'motor', or due to a resistive connector contact, a broken wire, a failed transistor switch, or a faulty MCU port.
How to Turn on 17 Built-In-Test is operating normally.
I'm not sure why you ask about "BiT#17". That one applies to particle debris sensing. Bit#18 runs the Fan motor test.
Pin MCU which is responsible for the Init Vacuum Motor?
To my knowledge that information has not been made public. Any way, your fan-motor troubleshooting can proceed nicely without that datum.
In addition, you can not perform a reset by the (SPOT + DOCK 10s)... a reset is not quenched CLEAN and silent melody, ...
I do not have any direct reply that associates intermittent fan-motor operation with your described RESET response.

If you have not run all BiTs (via Manual Advance), I suggest you do that and report any anomalous results.
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Re: Roomba 625 Vacuum motor turns on and off

Postby przemo33 » March 11th, 2015, 6:29 pm

Thanks for the reply,

When you turn on the Built-In-Test (of course 18) when the engine is running normally all the time,

However, during the operation (by pressing CLEAN) and once again did not work.
(voltage occurs once and once there J6)

I checked other Vacuum Bin and it is the same :(.

What can I check and how?
Is it possible to somehow get around to turning it on, or in some other way?


Oh, and what about this "reset"?

Best regards
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Re: Roomba 625 Vacuum motor turns on and off

Postby Gordon » March 11th, 2015, 8:22 pm

przemo33 wrote:Thanks for the reply,
Welcome!
When you turn on the Built-In-Test (of course 18) when the engine is running normally all the time,
Sorry, that is not clear to me, so I mentally translate it to say: "... (of course 18) then the Fan Motor is running normally as long as I wish."

And here, too:
However, during the operation (by pressing CLEAN) and once again did not work.
...I obtain this meaning from those words: "However, by pressing CLEAN, to start a cleaning mission, once again the vacuum Fan did not work."

If my understanding is correct, tell me what other motors in your 625 became powered after depressing the Clean button.

For this statement:
(voltage occurs once and once there J6)
...I must presume that you used a voltmeter across pins of J6 to confirm Fan Motor power reaching that point. If so, what voltage did you measure?
...What can I check and how?
I think you have shown all suspects in my earlier posted sentence: "The fault can be in the 'motor', or due to a resistive connector contact, a broken wire, a failed transistor switch, or a faulty MCU port", to now be clear of guilt. Hence, some other (non fan sub-system) cause for 625's problems must be found. See my closing sentences.
Is it possible to somehow get around to turning it on, or in some other way?
iRobot provides no alternate command options that can be run while the robot is processing Clean-Mode firmware. Maybe some other rr-member will post an idea.
Oh, and what about this "reset"?
For now, simply R&R the battery to accomplish a system reset. The two-button-press Reset should become operational after you correct what is really bothering the robot.

Since you have not run ALL BiTs (via Manual Advance), I suggest you do that and report any anomalous results.

In addition, you should report measured data that reveals your battery's current state of health.

Best regards.
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Re: Roomba 625 Vacuum motor turns on and off

Postby przemo33 » March 12th, 2015, 3:36 am

Thanks for the reply,

Sorry for my English,
Again, I will describe.

When I turn on the Built-In-Test (test 18) - the engine is running normally all the time without break. (J6 voltage 12V)

In normal mode, cleaning (by pressing Clean) - the engine runs for a few seconds and then turns off for a few seconds and so alternately
(voltage 12V and 0V J6 alternately)


I checked "Vacuum Bin" with the other Roomba 625 and is the same :(.

In summary,
- The motor is - OK
- Contacts connection Vaccum Bin - OK
- Cables - OK
- Transistor switch (Q79) - how to check? (I noticed the changes the voltage when the engine OFF and ON)
- MCU - I do not know how to check (do not know which "PIN" in U8)


Best regards
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Re: Roomba 625 Vacuum motor turns on and off

Postby Gordon » March 12th, 2015, 1:15 pm

przemo33 wrote:...When I turn on the Built-In-Test (test 18) - the engine is running normally all the time without break. (J6 voltage 12V)...
I think "12V" is way too low. This low value suggests your battery is not able to properly power the Roomba!
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Re: Roomba 625 Vacuum motor turns on and off

Postby przemo33 » March 12th, 2015, 1:38 pm

The battery is OK, running 2 hours
12v is on pins Vaccum Bin unplugging it as it is about 15V
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Re: Roomba 625 Vacuum motor turns on and off

Postby Gordon » March 12th, 2015, 6:44 pm

przemo33 wrote:The battery is OK, running 2 hours
"Running 2 hours" gives the battery a good report--so long as the test was for the robot running a cleaning mission for two hours; ELSE, a poor report, if battery simply operated the Fan Motor and operating system in BiT-mode for two hours. Please clarify.
12v is on pins Vaccum Bin
Sorry, but I do not have the R3-Fan-Motor Sub-system schematic, so I can't be emphatic (like I know precisely what I'm talking about), BUT, I expect for you to measure almost the full (maybe one volt shy) battery voltage across a running R3 Fan Motor. I doubt that the R3 schematic is greatly different than what we have seen in R2-Roomba. For reference, here is the R2-schematic: Image Refer to this post to see or copy the entire image: viewtopic.php?p=29586#p29586
unplugging it as it is about 15V
That is a very large change in voltage! Your 625's Fan Motor may be ailing, i.e., drawing way too much current. Or, there could be a fault in the motor-driver circuit that shows only when its transistor switch ("Q79", I believe you said) is commanded ON.

Amongst other "SUMMARY" records and automatically stepped BiT mode will print a line like this for the "vacuum-current exam:
page-46 Service Man'l wrote:SUMMARY: (vacuum-current-ok?) PASS mA -143 min -230 max -50 mV 15947 degrees-C 37
If you know how to translate that stuff into something meaningful, you will obtain the allowable current limits for your R3-Roomba's Fan Motor operation. Reading the line backwards, it says:
    1) When motor current was assessed, the temperature of the battery was 37C.
    2) Battery voltage was 15.9V.
    3) 230 mA is the maximum assigned motor current.
    4) 50 mA is the minimum assigned motor current.
    5) At test time, 143 mA was being drawn by the motor, hence BiT#18 passed.
Elements (3), (4), & (5) are assigned negative values because current through the system-current sensor detects a negative voltage across the system current shunt. Note that when charging of the battery takes place, current goes the opposite way through the shunt and a positive voltage is sensed. In addition, the ill educated writer of the Service Manual thinks that "-230 mA" is smaller than "-50 mA", hence "min -230" & "max -50", thus all load current limits are expressed backwards in the manual!

Now then, by using your "Q79" pointer, coupled with the old R2 schematic7, I have been able to flesh out a portion of the R3 Fan-Motor driver schematic. Lets take a look.

Viewing the top face of 625's main Printed Circuit Assembly (PCA), and with it turned to position the curved PCB edge away from you, Roomba's left edge will be at your left, and its right edge at your right.

The Bin's PCA-mounted jack will be at the right, rear (close to you) PCB corner.

TO-92 cased Q79 transistor, (xstr), mounts to the PCB from its underside, but the three pads of Q79 are easy to access for voltage / continuity measurements on the top-face at coordinate x=24 mm, y=98 mm with respect to, (wrt), the PCA's Clean-switch center, (0,0).

Q79 is a BJT-S8050 xstr of NPN polarity.

Q79's base pin, (b), soldered to the center pad. Its emitter, (e), is soldered to the left pad, and its collector, (c), is soldered to the right pad.

Using Roomba-R2 Impeller Motor Driver's schematic as a template, I will descriptively overlay Roomba-R3 component markers so you can visualize the power control portion of your 625's circuit.

Note that I did not pursue detailing R3's Q79 'driver', such as the R2-Q18 xstr. I will only point to it as Q15, located at (14,88), a SOT-23 "2X", NPN xstr. If the 625 does have an excess current fault, I doubt the fault will involve Q15.

Now, looking at schematic7, for the R2-Roomba, I begin matching R3 markers with the R2-markers in the schematic:
    a) Supply voltage "V_batt_pos" is R3's "VBAT", a.k.a. "J17". Also, D20K connects to this supply, as does R3's D54K to VBAT.
    b) Bin connector "J17" is R3's "J6", its left pin.
    c) "Impeller Motor" = R3's "Fan Motor".
    d) The low voltage terminal of the Fan Motor connects to R3-J6's right pin. Also, D20A and Q35c are on this node, as will be R3's D54A and Q79c.
    e) Q35e passes motor current into R2's shunt resistance "R173", and R2's "R142" contributes to sampling the voltage developed across R142. R3's current shunt resistance is "R182", ~ 121 ohms. I did not identify R3's voltage tap resistor.
    f) R2's Q35b is pulled HI to switch the motor ON. R3's Q79b is also pulled HI when the Fan Motor is required to operate.
    g) R2 uses a 100 ohm resistor, "R124", to limit Q35's base current, but R3 uses larger 470 ohms "R181" to do that limiting.
    h) In both robots, motor current is returned to system ground, which is noted by TP#206 on the R2-PCA. On R3's PCA, system ground, (SYS_GND) is known to be the right-end pads of parallel, power resistors "R235" and "R257" -- see these just to right of PCB "GND", a.k.a. "J14" marked on the PCB.
From the above information, you should see that monitoring Q79b, wrt SYS_GND, a.k.a. signal return, is a reasonable thing to do.

You should also verify the resistance value of R182, for if it has drifted to a larger value, a larger sample voltage will be seen by the MCU even though the correct, nominal motor current is coursing through R182!
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Re: Roomba 625 Vacuum motor turns on and off

Postby przemo33 » March 17th, 2015, 2:29 am

Hello,
Thank you very much for your time.

Unfortunately, I could not fix it. Additionally did some short and I fell completely :(

Yours
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Re: Roomba 625 Vacuum motor turns on and off

Postby Teilchen » February 28th, 2019, 8:00 am

Sorry for digging this topic out, but it seems I have a similar issue with my Roomba615 robot.
The vacuum turned on and off during the cleaning cycle, pretty much as the topic starter refers to.

I can see the diagram, and I have found the corresponding components on my PCB, however, I do not seem to understand, why the BIT would state a correct current reading, and the cleaning cycle would shut the vacuum on and off without throwing an error code of some kind...
I mean if a current sensing resistor would drift away from its original value, the current reading would not be inside the limits. And if it is during the BIT, why would the MCU Pulse the vacuum?
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Re: Roomba 625 Vacuum motor turns on and off

Postby Kelad » February 28th, 2019, 3:37 pm

You sure its not the bin motor? Put a 9v battery on the bin terminals...does it run ok?
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Re: Roomba 625 Vacuum motor turns on and off

Postby Teilchen » March 1st, 2019, 2:12 am

Yes, th BIT runs fine as I have mentioned...
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Re: Roomba 625 Vacuum motor turns on and off

Postby vic7767 » March 1st, 2019, 2:34 am

Remember, when the Bits are active, ALL sensor monitoring is terminated.
Roomba and Neato Mods, come visit: http://www.vic7767.com/
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Re: Roomba 625 Vacuum motor turns on and off

Postby Teilchen » March 1st, 2019, 4:15 am

Thanks for the tip! But what sensor would stop the vacuum during the cleaning cycle without throwing an error?
Again, during the BIT the vacuum runs over a long period of time, and the current consumption is well within limits, and pretty close to a direct test with a lab power source...
If a component would fail under the load, it would also fail during the BIT, I suppose.
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