[font=Arial][size=2]Roomba 595
After a mobo swap, this 595 immediately stops with an “uh-oh”, single-beep alert, and “move roomba to a new location…” message, then will not to budge. This behavior is repeatable and consistent. I ran BiT in manual mode and found that both inner cliff sensors and the left outer sensor are not detected. This problem is new since swapping the mobo; the 595 did not have this problem with the original mobo. I have the 595 apart, the mobo removed, and the four cliff sensors out.
At this point, I need to determine if the cliff sensors have failed, or if the mobo is at fault. I have no idea how to bench test either. Sooo… I’m stumped.
Any t’shooting suggestions?[/size][/font]
Hi,
Is it possible that you have installed the sensors at the wrong place?
It could possibly be an issue with the new motherboard you have purchased.
What was the issue with the old motherboard exactly? Is it possible for you to swap it back and see if the sensors are defective?
Can you please send us pictures of your connections? We will verify if they are correctly in place.
[size=2][font=Arial]Thanks for your[/font][/size][font=Arial][size=2]reply, [/size][/font][size=2][font=Arial]Mathieu[/font][/size][size=2][font=Arial]. I’ll answer your questions in order.
[highlight=#ffffff]“Is it possible that you have installed the sensors at the wrong place?”[/highlight]
I swapped the motherboard; I didn’t touch the sensors other than to dis/reconnect them.
[highlight=#ffffff]“It could possibly be an issue with the new motherboard you have purchased.”[/highlight]
Agreed. The BiT (manual) test indicated that a problem with the cliff sensors. The test does not tell me definitively if the problem is with the cliff sensors or within the motherboard. And for the sake of clarity regarding the BiT results: during tests 3 and 4, the “Dock” and “Spot” lights illuminate when the sensors are not blocked, and go dark when they are blocked. In my case, the the “Dock” and “Spot” lights did not illuminate for three of the four sensors. I dunno if this means the xmit/rcvr IR LEDs are bad; but it seems to indicate that the mobo interprets the signal between it and the sensors as “closed”, I guess.
[highlight=#ffffff]“What was the issue with the old motherboard exactly? Is it possible for you to swap it back and see if the sensors are defective?”[/highlight]
A transistor fried (see image below). The mobo was completely unresponsive. It now resides in the county landfill where some sentient semi-transparent mecha-beings might dig it up at the end of the next ice age.
[highlight=#ffffff]“Can you please send us pictures of your connections? We will verify if they are correctly in place.”[/highlight]
I’m pretty sure I didn’t reconnect the harnesses incorrectly. In fact, I don’t think its possible to do that. 1) disconnected plugs hang directly in line with their respective receptacles on the mobo; 2) adjacent plugs-and-their-matching-receptacles are different shapes; and 3) the wire lengths are just long enough to reach their targets.
While I remain skeptical that three of the four cliff sensors have suddenly gone wonky, your question about the nature of the failure of the original motherboard has me thinking. Is it possible that the transistor that got fried also somehow zapped the IR LEDs in the sensors as well? Take a look at the images (below) of the original mobo. The arrow indicates the transistor that fried.[/font][/size]
Maybe the transistor at Q79 interfaces with the cliff sensor array downstream?
Hey,
Thank you for your reply.
The fact the transistor fried could certainly have affected the cliff sensors.
Right now, there’s pretty much two diagnostics:
Either the cliff sensors are defective or the new motherboard is.
The fact that 1 sensor is being detected, we would consider the sensors before the new motherboard.
The cliff sensors are bad.
I swapped in a known-good cliff sensor array into the 595. I immediately ran the BiT, tests 3 & 4 (passed), then started it up. The thing works as expected.
Props to you for your intuition, Mathieu. Guess that which zapped the motherboard also wreaked havoc with a fistful of IR LEDs. …hmmph.
Problem solved… for now.
