Roomba 560 not working brush

[przemo33]

Hello,
I my roomba 560 not working brush.
(I tested on three different modules)

In BIT 16 test brush shall be attached in only one direction and then silence.

I think it's not a signal comes from the motherboard.


Please help.

Best regards.

[a1robotrepair]

See Thread "560 brush motor not working" on page 2 in this forum to find the answers you seek.

To point you in the right direction, I would start by check the solder joint of the forward PNP transistors emitter connection to V Bat, 0 ohm, and the forward NPN emitter connection to Bat -, 0.15 ohm.

[przemo33]

Hello,

Where are these components on the PCB?
(I understand that it is a H-BRIDGE?)

Regards

[przemo33]

Hello,
I changed one diode in the H-bridge, but further brushes do not spin the other way.

[a1robotrepair]

See Thread "560 brush motor not working" on page 2 in this forum to find the answers you seek.
There you will find pictures of the circuit board, links to other threads that have suggested ways to troubleshoot that circuit and drawings of a typical H Bridge circuit.

The transistors are the 4 large side by side 3 legged devices on the bottom side of the PCB with bolts to their heat sinks.

[przemo33]

Hello,





I changed element highlighted in red (it was broken), and continue the same symptoms.

Should I to change it all FET?


How check the solder joint of the forward PNP FETs Drain connection to V Bat, 0 ohm, and the forward NPN FETs Drain connection to Bat -, 0.15 ohm. (You could show / describe where this measure)

Regards

[a1robotrepair]

top side shows transistor solder connections
black marks shows collector transistor connections to pin 1 of brush connector.
purple mark shows collector transistor connections to pin 2...
red shows VBAT connections to PNP transistors emitters.
green shows GND connection to NPN transistors emitters.
Q82 is forward PNP, Q66 is forward NPN
Q81 is reverse PNP, Q67 is reverse NPN

Diode checker in circuit without battery, check from base to emittor of the PNP transistors and from emittor to base of NPN Transistors. All should read about 0.6V.
both black marked solder joints should show 0.0 ohms to pin 1 of brush connector
both purple marked solder joints should show 0.0 ohms to pin 2 of brush connector
both red marked solder joints should show 0.0 ohms to VBAT
both green marked solder joints should show 0.15 ohms to GND





bk=black p=purple r=red gr=green

[przemo33]

Hello,
Thanks a lot,
I replaced the two elements Q82 and Q67.
And it works.

Regards

[TechGuy]

I like to thank you a1robotrepair for the quick test guide on repairing H-Bridge circuit.

Yesterday, I went through a 500 series Roomba repair marathon using the information on this thread on H-Bridge circuits. All boards were water damaged.

Board #1 with main brush motor H-Bridge
Board #2 with all 4 H-Bridge circuits were damaged
--- Left and right wheel H-Bridge circuits
--- Main brush motor H-bridge circuit
--- Side brush motor H-Bridge circuit
Board #3 with left wheel H-Bridge circuit

I did the quick measurements suggested by a1robotrepair to make sure that there is not burnt trace or open components before testing the power transistors. For the board #2 left wheel H-Bridge, green marked solder joints to GND was open at R73. After replacing R73, it was easy to locate the faulty power transistor(s) and fixed the left wheel.

Tips: At the start, I use my solder sucker to get the transistor off the board without damaging plated through holes. This method is time consuming. After a few transistors, I found a better procedure.
1. I added low melting point solder to mix with the board solder.
2. I use the soldering iron tip to melt the solder on all three leads.
3. I gave the board a gentle shake while the solder is in fluid state. The transistor will fall off the board easily.

Next repair marathon will tackle the H-Bridges on my 880 and 780 boards. It is time for me to practice my skill on SMD components first.

[a1robotrepair]

TechGuy, a Canadian hero!
Thanks
I put together a post listing urls to some good trouble shooting posts.
http://www.robotreviews.com/chat/viewto ... =4&t=19533
Last year taking on major commitments.
I'm traveling and tinkering starting 2018, god willing.