Bench measurements and trace analysis:

- Pin 2: GND (Vcc-)

- Pin 5: 10V Vcc+

- Pins 1 & 3: AC line phase monitoring (zero-crossing/heartbeat inputs)

- Pin 4: Output running through a 10k resistor to the anode of a PC817 optocoupler (cathode to GND), sending the power-available heartbeat signal across to the secondary-side processor board.

Because Pin 4 drives an optocoupler LED via a 10k resistor rather than a standard logic trace, an open-collector/open-drain output configuration is actually required (sinking current through the optocoupler). We are looking for an exact cross-reference or identification for the '21ASP' SOT-23-5 IC matching this open-collector comparator or logic function.

Since replacement power boards are unavailable, does anyone know the exact cross-reference or functional equivalent for this IC?

⟐ Answered August 27, 2026 at 5:04 MST

⟐ Commented August 26, 2026 at 0:33 MST

⟐ Commented August 24, 2026 at 18:09 MST

Edited to add: I checked the voltage on the docking station and it is getting voltage. The feet on the docking station are springy so they are not stuck. Everything has been cleaned with rubbing alcohol.

Edited again 8-24-2026:

Changed the battery out, but the behavior persists. Suspect it is probably the charging board. Firmware update requires installing an app that wants far too much information for the purpose it fills. No way am I going to turn loose a robot from Shenzhen, China on my WiFi network that is all ready having issues with a ton of personal info. I don't see any other external ports to plug the robot in via usb either. Will put this in the junk pile. Maybe some other parts will find their way here someday and I can cannibalize those pieces into one working machine.

⟐ Edited by author August 24, 2026 at 17:39 MST

When attempting to register, it says device needs factory reset. After performing factory reset, it says it failed and to try again. I also do not hear any tones or sound. Any recommendations? I've tried numerous solutions but nothing seems to work.

I switched off both the loader and the robot. Then I switched on both the loader and the robot and got an undefined signal: upper lights on, middle and under lihgts flash.

So what can I do?

R1138 model

⟐ Commented August 18, 2026 at 2:31 MST

⟐ Answered August 13, 2026 at 11:01 MST

⟐ Commented July 30, 2026 at 0:09 MST

recently the main brush motor stopped spinning so i opened it up to replace the motor. i have now bought 3 different replacement motors that say they are for the T8 or 8x. but none of them fit correctly. i have searched like crazy but can not for the life of my find my motor anywhere online. (pictures below) am i crazy? are these no longer in production? is one of the other motors supposed to fit even though the L shape is wrong? your wisdom is appreciated.

ok so with some inspiration from oldturkey03 i think im close. im going to walk through what i did if anyone else is ballzie enough to try this.

so i decided i was going to transfer the old L drive shaft to the new motor. i started by unclipping the snaps around the perimeter (picture1).

once inside i cleaned all the gears as they were very full of dirty grease (picture2).

i then removed the two screws on the left side of the image (picture3) (this is where the motor attaches) and screwed in the new motor.

but as i put it back together i realized that the gear attached to the new motor was beveled to the left but all the old gears were beveled to the right! so i pried the motor gear off of the old motor and transferred it to the new one. (be careful when prying off it toke a lot of force and mine ended up half way across the room in my white shag carpet. much cussing ensued.)

ive got all the pieces together and clean now i guess the last thing i need is to figure out what kind of lubricant to use on the gears. any ideas?

⟐ Commented July 26, 2026 at 12:09 MST

⟐ Commented July 21, 2026 at 14:43 MST

⟐ Commented July 15, 2026 at 18:28 MST

i bought a batrie to my roombai7 that you said that was compatible but my roomba said that not ricognize

⟐ Answered July 11, 2026 at 18:48 MST

I'm trying to figure out whether I'm dealing with a hardware fault or a software/firmware bug on my Roborock S7 Max Ultra.

Firmware: v02.26.80 (currently up to date, per the app)

The problem: After the robot finishes a cleaning cycle, it does not automatically empty its bin into the dock. This happens regardless of whether the auto-empty setting is on "Smart" or "Max."

What works fine:

If I manually trigger emptying from the app, it works perfectly every time. Even when the robot's onboard bin is completely packed full (mostly dog hair), the manual empty cycle pulls everything through into the dust bag in the dock with no issues.

What doesn't work:

• The automatic emptying after a cleaning run simply never triggers on its own.
• The bin indicator in the app never turns red/full, even when the bin is genuinely packed solid. The robot will happily keep cleaning with an already-full bin instead of stopping or flagging it.
• Eventually I do get an "empty ASAP" notification, but given the above, I suspect that's just timer-based (e.g. "X days since last empty") rather than tied to an actual full-bin reading.

Has anyone dealt with something similar? Is there a known sensor (e.g., bin-full sensor or dock contact sensor) that could cause this exact symptom, or is this more likely a bug that needs a factory reset or re-pairing to fix?

Any troubleshooting tips or shared experiences would be appreciated.