My Roomba 570 has the dreaded nine beep issue, and after researching this board I tried the onboard diagnostics with the following result
Test 2 shows both left and right bumper sensors being stuck on.
I can understand one sensor failing but both failing at the at the same time leads me to believe there maybe something else wrong besides the sensors themselves.
Has anybody come across this issue before ?
Thanks
Roomba 570 Nine Beeps
- vic7767
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Re: Roomba 570 Nine Beeps
I've had both left and right sensors fail just not at the same time. In your case it may possibly be something else but replacing the IReds wouldn't hurt. While you're disassembling you may discover a poor connection from the sensor array connector and the PCB.
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Re: Roomba 570 Nine Beeps
Quite right. As vic767 alludes, there is great possibility of an open circuit due to a poor solder connection or failed open semiconductor in the IREDs' power string. Do take a tour through tnoone's thread and study the wiring verbiage:Scotty59 wrote:My Roomba 570 has the dreaded nine beep issue, and ...I can understand one sensor failing but both failing at the at the same time leads me to believe there maybe something else wrong besides the sensors themselves. ...
http://www.robotreviews.com/chat/viewto ... 984#p75984
If you then want to dig in and get your hands dirty just let me know. I can provide newer information about some voltage test points. You would be checking voltage on a couple pins (topside) of this bottom-side mounted J11 jack: and at pins of the BUMP-IREDs' power-switch, xstr Q61 (out of view beyond left edge of above photo's frame). In addition, touching specific pads on the sensor-module boards (shown by tnoone) with your DVM's probes may be required.
Last edited by Gordon on July 1st, 2011, 11:38 am, edited 1 time in total.
Re: Roomba 570 Nine Beeps
Thanks Gordon, if it wouldn't be too much trouble I would appreciate the information
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Re: Roomba 570 Nine Beeps
Sorry about the delay, but just about the time I read your message I also discovered a flaw in my assessment of the transistor that is in series with the two IREDs. I had to go back to work to find out what was going on.Scotty59 wrote:... I would appreciate the information
Instead of using "Q56" in the circuit, I should have been talking about "Q61" as the BUMP-IREDs' driver! I was misled by colors in published pix of the P11 harness by taking an orange (ORG) color to be RED.
In this post I show a schematic that is admittedly incomplete, but should satisfy your troubleshooting needs. Features omitted from the schematic are: a) a few bypass capacitors, and b) the control-signal path from MCU to this circuit's driver input. There is no mention of the IREDs' sensor-partners, i.e., their photo-transistor radiance detectors, since they have no circuit relationship to IREDs' faults, and have historically not been prone to failure.
Another qualifying bit of info is all of my work is derived from working only with a loose main board. I do not have on hand (other than in my operational 535) the IRED pair and wiring harness. You will see that I had to resort to connecting a test resistance to the board as a means to determine the probable IREDs' current level. I looked at the IRED's data-sheet to find its FWD voltage drop at 30mA FWD current is ~1,2 volts (NOM.). So, R_TEST = 2*1.2V / 0.03A = 80 ohms. I used a resistor that measured 83 ohms to emulate and carry IREDs' current.
Now, with that preamble dispatched, here is a schematic drawing that fairly well represents the power path through the IREDs and their driver xstr: I'll give you a minute to look it over...
Once you connect Roomba's battery, then VBAT and +5VREG power supplies are distributed around the board, and the robot is in (what I call) the Standby Mode (STBY). which is awaiting an operator's instruction, or a scheduled instruction to do something. No lights are lit in that condition.
After you momentarily depress the Clean button, the robot goes into the ready-to-Clean-state, and awaits the next Clean button push. My loose 510 board lights up its GRN Clean-button LEDs, then waits.
To begin your troubleshooting I think you would like to have left all the motorized modules removed from the robot, and you need test access to the top face of the main board ("mobo"). The Bump-Switch Sensor boxes may be open or closed to start with.
Unless otherwise indicated, all voltages are measured wrt the huge plated through, but blocked, hole named "GND" & "J14" on the upper side of the mobo. Hand directions (such as left or right) are relative to Roomba's left or right. Stand behind Roomba, then your right & left and forward & rearward directions conform to Roomba's.
STEP-1) With the robot in STBY mode measure & record "VBAT" (J15) voltage; and measure and record the +5VREG voltage. (An easy to access spot to measure the five-volts bus is on the plus pin of e-cap C287. That e-cap is mounted via the PCA's lower face, but its pair of pin pads on the upper side may be located at a coordinate position eight millimeters left of Roomba's fore/aft centerline and about 96 mm forward of the Clean-switch center).
One of C287's solder pads is square, while the other is circular. Measure to the square pad (the round pad is ~GND).
STEP-2) With the robot in ready-to-CLEAN state (one brief press of Clean from STBY state), measure & record "VBAT" / J15 voltage (the value should not have changed from that found in step-1).
Remain in the ready-to-CLEAN state, and viewing upper face of the mobo.
STEP-3) Measure & record YEL/GRN_wire voltage (can access at J11[1,8] solder pad. "[1,8]" means: Far right pad in the FWD row of eight J11 pads.
STEP-4) Measure & record ORG/GRN_wire voltage (can access at J11[2,8] solder pad. "[2,8]" means: Far right pad in the aft row of eight J11 pads.
If the YEL/GRN_wire voltage is not less than the ORG/GRN_wire voltage, there is either in open in the IRED's path, or Q61 has not been commanded ON.
STEP-4) Measure & record V_Q61e. If there is an open in the IREDs' path AND Q61 has been set ON, its collector voltage may be around 4.8V. If Q61 has not been commanded ON, V_Q61c will be ~zero, and suspicion falls on input driver xstr Q6, or earlier parts -- the latter being assumed to be quite unlikely.
If you need guidance for touching e, b, c terminals on these xstrs here is a photo-guide to them:
Contrary to what we see in the pic, the SOT-23 case is a lot smaller than a TO-92 case -- about three SOT-23 case would fit inside the TO-92's plastic.
Transistor Q6 is located on mobo's upper face at about 16 mm to left of e-cap C287's pads.
At this point you have shown that power is available to the IREDs, and their power-control device (Q61) has been told what to do, but no current may be flowing through those IREDs. With that result, you must now go inside the Bump-Switch boxes to probe terminal pads on the small PCA contained in each box.
Since I have no idea whether you will follow this plan, or what your electronic test capability (access to test jumpers and various size small wattage resistors) might be, I will simply outline tactics that should pin point the location of the continuity break.
Watch for any errors I might have made in this area, since what I say is based only on what I can see in tnoone's pix of those two small PCAs!
A) While monitoring Q61c, to see if it rises to around +4.8 volts, jumper-connect a test resistor (80 to 200 ohms) from J11[1,8] to J11[2,8]. If Q61c rises, that insures the fault resides in the J11 harness going round trip through the IREDs.
B) Following the appropriate result from (A), momentarily jumper-contact (needle-like probe tips clipped onto) a zero ohm test lead from J11[1,8] to the indicated pad on the Bump-SW-PCB it goes to.
(i) First touch Bump-SW-PCB pad #1, and observe V_Q61c action to check the ORG/GRN-wire.
(ii) If no action at that point, visibly follow the copper track from pad #1 to the IRED's anode, then touch D1's anode solder pad and watch for V_Q61c's action, to check the ORG/GRN-wire's solder joint.
(iii) If no action at that point, touch the actual lead-wire coming from D1 and watch for V_Q61c action to check that solder joint.
C) If (B) reveals nothing, then perform similar bypass shorts, referred to J11[2,8], of the YEL/GRN_wire and subsequent solder joints, all the way to the other D1, and to its cathode, (K), at pad#2.
D) If (C) reveals nothing, then perform similar bypass-shorting of the WHT (PCA interconnect wire) harness wire and between joints of the first PCA's IRED cathode, (K), to the anode, (A), of D1 on the 2nd PCA. This is to include pad-joint checks where the WHT wire is soldered to pad #2 on one PCB & pad #1 on the next PCB (be careful to distinguish).
The above work should highlight the faulty area.
Let me know if you have any questions.