fix faulty non working Maytronics Dolphin M500 pool robot complete diagnosis and repair

[@TonyTony-by2vr]

One of the best do it yourself, disassembly and reassembly videos I’ve ever seen in my life. Mic drop.

[@Dentinvent]

After that nice comment, I have to watch it again myself. Many thanks . I am planning to make more videos with some other models ( starting from a broken machine to complete diagnosis ).

[@johnburgess8758]

Hi Dentivent and thanks tons for your video. I am really hoping you can help me with my faulty machine. About a week ago I noted that my Maytronics DB2 Robotic Cleaner D9440H - 20/07/2021 was moving forward about 10cm and then backwards about 20cm and then it would stop. Yesterday, I took it out of the water, checked that there was no visible obstructions, cleaned the impeller and then did the upside down out of water test. It was during this test that I noted that there was a clunk after every rotation. It operated for approximately 15 or 20 seconds and then stopped for about 5 seconds and then started up again, but it did not turn itself off (with the continual clunk every rotation). I turned it off, put it back in the pool and it did the same thing; forward 10cm, back 20cm and then would not move. Today I have removed the track covers and confirmed that there is no blockage. I hand spun the cleaner rolls and noted that there is a 'clunk' on every rotation. I then tried the upside down out of water test again; however this time the tracks moved very slowly for approximately 2 seconds and then it stopped. I waited approximately 2 minutes and it did not commence operating again, so I turned it off. Can you please suggest anything with this one? Cheers, John

[@Dentinvent]

Glad to help. I’ve fixed two DB2 machines in the last few weeks . They are similar to the S200. The clunk is most likely why it is not working . I’d take the tracks off and spin the wheels to see if you have a broken gear or the gear is not engaging properly. Let me know what you find.

[@nomnob]

Your video is great. I’m about to give up my 10 years old Dolphin supreme m3 and try one of the Chinese battery robot from online. But you made me feel like I still have something to do before I give up!

[@Dentinvent]

That’s a great comment. Makes me feel warm and fuzzy inside . Many are going the cordless robot way . I still always prefer the corded models which don’t run out of batteries . I’m making some videos on restoring the corroded , sticky cables .

[@1chrisandrew1]

This is an amazing walkthrough. Thank you very much

[@Dentinvent]

No worries and thanks for the reply. Any problems and I’ll try and help you out . I’m making a video to check the bearings and current draw.

[@alexvengerovsky2812]

@dentinvent - thank you for the detailed and thorough explanation! Very useful. On my M5 with tracks and rollers removed, the dry test goes well on one side (~10 sec) but on another side the motor stops after 3 sec. Before opening the motor I wanted to ask the expert - thoughts?

[@Dentinvent]

I always thought both sides operate for the same time . I’ve taken many of the motors apart and I’m making videos on current draw and bearing changes. The robot in the video ended up stopping all the time . I took it apart and compared the two sides and one drew more current . I changed the bearing on the high craw motor and … it works like normal . Still working on that video of you want me to make it . I did note high draw current does make the robot stop completely.

[@Dentinvent]

If you open the motor it usually seals back well and you get a chance to check moisture inside it so that’s a bonus .

[@NN-tk7uw]

Thanks for this helpful video! Our unit has a 3-pin cable and I think the power supply is faulty (erratic voltages). Do you know the expected voltages at the power supply socket? 30V between which pin numbers, and what about the third pin? Thanks for any help!

[@Dentinvent]

I’ll check when I get home but the third voltage is very low like around 5 volts and that is only used to change floor/wall/ water line selections . Best place to check voltages would be the power supply and then check at the robot end but you have to take the cable out of the robot so make sure you silicone grease the connection well and check for corrosion inside the motor box connection . Also do not over tighten that white ( or black ) nylon nut .

[@Dentinvent]

If your multimeter lead is negative on pin 3 the 29 volts DC is pin 2. There is a signal voltage on the third pin . I can check what that is if you want but be careful that you are using a good quality meter as some of the low end meters can give fluctuations.

[@NN-tk7uw]

@@Dentinvent Hmm, with the robot unplugged, I'm getting nothing between pins 2 & 3. Keeping neg lead on #4 I get +5V when the app says it's not cleaning and -16.7V when I hit start. Good quality Tektronix DMM. I think the supply is busted. I removed the connector and the familiar stench of burnt electronics was intense. Thanks for hanging in there with me! Any info on that control signal would be great. I'd like to get this running using my benchtop supply as a temporary fix but not sure if I need a command signal or just give it the 30V.

[@jamestsoi6506]

I have a Dolphin Sigma cleaner but very similar to your machine (about 3.5 years old). Mine runs a few feet and then stops with the red light shown on the power supply unit. I did the upside down test and it is fine. I have replaced the guide wheels, tracks, climbing rings and brush set; but the problem still persists. Since it passed the upside down test, so I assume the problem is not with the electricity. Or I may be wrong? What can be the problem? Will great appreciate any advice.

[@Dentinvent]

Strange if it passes the upside down test . When the wheels run with robot upside down does it look smooth? If it has a central active brush , often the bearings go and cause the gears to run crookedly . This can make the robot stop . If the gears of the active brush look suspect , remove the active brush completely and see if that works . What in the red light on power supply ( what does it mean ?) show .

[@rickbickerton4618]

M500 powers up in water but then shuts down within 10-15 seconds. I disassembled down to and including motor box ...all dry. 28V at cable end. Connections clean (gold). The unit was tested upside down as the video suggests it runs one drive for about 5 seconds then the other drive...so all good. when I placed the unit in the pool. It powers up but within 15-30 seconds it shuts down. Any suggestions.. circuit board gone? The motor has been replaced once.

[@Dentinvent]

When it was upside down , did the wheels spin smoothly ? I found one two weeks ago that the pool shop said it was a blown motor and it was actually the active brush bearings broken causing robot to just stop . Have a look there . Other place it can be is the bearing of the impeller motor . I’d check the active brush bearings and get back to me . One way to check is to have it all back together and take the active brush right off and see if it runs . Let me know .

[@nickwesterkamp103]

Hey man - great video but still having issues- it does the test cycle fine and the impeller goes - put it in the pool and it just says nah - it had some debris wrapped around the impeller and was a bit stiff to start with but it’s humming on dry land / troubleshot everything else but just thinking it might be the impeller bearings with the extra resistance from the water making it say no more - any thoughts as it’s beyond a joke Cheers, Nick

[@Dentinvent]

Nick , After that video , I had a few problems ( coming up in a new video when I get to it ). I completely disassembled the black box and took the motors out . Seems like one of the motors had a stiffness in the bearing and that caused the robot to keep stopping. Another thing to check is the active brush wheel bearings . If the bearings wobble it causes stress on the drive and robot stops . Let me know how you go .

[@nickwesterkamp103]

@@Dentinvent Thanks on the prompt follow up. Here’s what miss temperamental has been doing. Stopped working so replaced the main drive rollers as teeth missing. Great, problem fixed - 3 weeks later same deal/- playing up going a metre each way and shutting down. Replaced the side bearings rollers for tracks /- goes again (for one cycle) and then nada again. Used a mates control box and it went fine for about 5 minutes and just stopped so back to same old - it doesn’t even turn on unless it’s unplugged for 15 - 30 minutes and then does it’s haka and that’s it again - so I think I’ll dismantle the drive motors and start there and then come back to the oracle and let you know how it goes. Appreciation again on your videos as they are very informative and it’s hard to find the proper oil in this day and age of information hoarding so top marks good sir!

[@nickwesterkamp103]

Success and joy finally - it was becoming like my nemesis or the better half lol But yeah, it required unplugging the two drivers in the black box and taking them out and then just unscrewing the two bottom screws on each and pull the bottom plate off that has the small switchboard attached - lots of carbon dust so blew it out with the central slide housing off. I then used 400 grit sandpaper and cleaned up the copper spinning bit and scraped the centres with a razor, sprayed with contact cleaner and wiped off /- also sanded the face of the two spring loaded small magnets on the switchboard and put back together /- trick with the spring loaded magnets was I looped the copper feed wire over the back of their guide runners / - put back together and put screws in and tighten up - then loosen them off just so you can see inside and use a small screwdriver to flick the wire off the runner so that the springs reengage and then tighten back up put back together and hopefully your away - cheers again Dentinvent - it’s always good to have the intel 👍🏿🤙✌️

[@whoknewit]

@dentinvent Hi I am working on my neighbors Supreme M4. I have continuity all through the cables and the correct voltage all the way up to the motherboard where the voltage reads the same as the box. The motors will run off the box when I jump from the box. but nothing happens after I reconnect everything. My neighbor said a rag was sucked into it. The tracks spin easily and motors work. Could it be the motherboard. It does light up though and give the correct voltage. I did use his other box that currently runs the premium model and no change. Thanks for any advice!!

[@Dentinvent]

That’s really interesting that if you run directly off the power supply it works but not with the cable . Sometimes voltage is not an indication of being correct . Can you swap the cable with another one to check ? Also is there any corrosion at the motor box - cable connection and is there any corrosion in the anti tangle swivel connector ?

[@whoknewit]

@@Dentinvent Funny enough I was thinking the same thing about the cable. His cable is fairly twisted. I could try his box and cable on his premiere and see if that makes a difference? I checked for corrosion through out the cable and connection and box, I did not find any.. Initially the inverter motor did not work so I got another off of Ebay so that is what is in there now. The replacement was the Exact same motor. The seal was new on the motor case so no water damage I could see. It never has tried to do the test part. Could it be the bearings on the drive motor causing too much resistance? I mean would it at least try to do something once all is connected? Right now it does nothing so that is why I thought the motherboard since both motors were turning? Thank so much for your thoughts on my problem. I will update you as soon as I try the other cable and box at the same time. Wow you should start your own forum and definitely the buy me a coffee thing on you tube. There are all kinds of people trying to repair these things :)

[@whoknewit]

@dentinvent Hello again. I tried my neighbors box and cable still a no go on his broken supreme robot.. I even tried the original power box through his cable and it started his premiere robot. I am guessing the motherboard? Any other ideas. The boards are just so expensive just to try one. Any other ideas?? About to give up..Thanks buddy :)

[@whoknewit]

@Dentinvent Just an update. I was able to get another board fairly cheap and everything started right up...Guess it was something on the board burned up. No obvious signs of damage. Thanks for the advice and help..

[@alessi1973]

Thankyou for producing comprehensive video. I have a question though. What should I be looking for when one of the dual motors continually stop working and requires the movement of the track in one direction or another to commence operating again. I have replaced the bushes inside the motor but it reappear once more, approximately 48 hours later. Should I be looking at the spindle shaft associated with the affected motor or is it sometime else?

[@Dentinvent]

Thank you for the nice compliment. I would take the motor out and spin in by hand . If it feels gritty or rough , change the bearing on the spindle of the motor . Message back if you have problems.

[@alessi1973]

They do not feel gritty. But I am happy to replace. Would you have part numbers of both sides aswell as the o rings? If not sizes possibly.

[@Dentinvent]

⁠@@alessi1973 I don’t have part numbers but best to look at the ball bearing nearer the water side ( near the long end of the shaft ). Use a flat piece of steel with a slot cut into it to fit the shaft and tap the motor shaft to remove the bearing and read the number on the bearing and buy off eBay or Amazon ( watch as some bearings are poor quality … cheap ones are the bad ones ).

[@pattiyohe4196]

I have an M500 cleaner. One of the climbing pads broke so we replaced all 4 of them. Now, the cleaner will move left, right, and rotate, but will only go forward about 2 feet. It shuts off after 5 minutes of rotating around. What can I do to fix it? Out of water test appears fine. Could it be the bearings? We are not sure which parts to order. Thank you.

[@Dentinvent]

If it worked when the climbing pads were old and worn, it possibly could be that the new ones are too tight . Are the pads genuine Maytronics ones ? In my video , this cleaner kept stopping afterwards and it was the bearings . I’m still making that video . I’d try swapping the climbing pads ( rings ) back and let me know if that works again.

[@pattiyohe4196]

@@Dentinvent Yes, they were genuine Maytronics parts. It makes sense that the bearings would stop the robot from moving. I will order new wheels. The tracks are is excellent condition. The active brush is missing most of its little tab brushes so that will need replaced. Thank you!

[@1chrisandrew1]

Hi - just adding another comment. I've followed your tutorial and repaired my M500. This is amazing thank you. For me it was the swivel cable contacts. One of them was pushed in - I had zero volts on the robot side. Could you add a donation link to your video or let me know your PayPal address please. I'd like to send you $20 as a thanks

[@Dentinvent]

Thank you for the nice comment. No need to pay me . You keep the money for future repairs . Remember if the pin ever pushes in too far and loses connection and you cannot get it out far enough , you can make the pin extension in my other video .

[@justfun-ij5xn]

What controls direction - the board in the motor or the board in the Power Supply? Replaced corroded board in motor housing now it starts impeller and drive motor right up and only goes in one direction - no self test happening????

[@Dentinvent]

The direction is controlled by the board in the motor . The power supply mainly just gives power and timer functions and can send signals to the motor to stay on floor etc. I think your problem is still in your motor box. Did you check the actual drive motors for current draw? I have found the actual current draw can affect start / stop of the robot . If only one of your drive motors is running, it will affect direction.

[@justfun-ij5xn]

@@Dentinvent it is an M4 so only one drive motor. Board must not be proper one as from eBay seller.......ugh.

[@Dentinvent]

@@justfun-ij5xn Best way to get a replacement board is wait for a broken robot to come up that does not work but assess to make sure it has no water into the motor housing (work this out by the seller's description of how the robot died). Don't buy one off ebay as the seller makes ten times the price of a broken robot.

[@pattiyohe4196]

I was hoping this video would help me fix my M500's bearings. You started out fixing an M500, but during the final out of water test, you are showing an M400.

[@Dentinvent]

That out of water test was actually a M500 set into the body of a M5 Liberty ( has no active brush in the middle of the robot body ). I’ll still make a video on the bearings. Did a heap of tests on current draw with old bearings and new bearings and strangely , seems like the new bearings were drawing MORE current ? Didn’t understand that but the new bearings on a machine which kept stopping would actually fix it. Stay tuned and I’ll make that video soon.

[@pattiyohe4196]

@@Dentinvent Thank you! I saw the active brush in the beginning, but it was missing at the end of the video. I was hoping to learn how to replace the active brush. I did learn how to remove the side panels to remove the wheels if I ever needed to replace the tracks. When I opened one side, there should have been a main roller bearing (4 circles with the bearings inside). There were only 8 ball bearings floating around. The two inner circles that hold the bearings were missing on that side. I found 1 smaller ball bearing inside one of the guide wheels. I opened the other side, and the ball bearings were inside the circles like they are supposed to be. I am ordering new guide wheels and pully gears today. When I removed the active brush's 4 screws, one side fell apart. It was missing one of the eight bearings, so that is where the small bearing came from. I could not get the ball bearings to stay inside on the one side that fell apart so something is broken. I am not sure how that one side is missing the center plastic parts. Not sure how they could have come off. This is the first time we have taken the robot apart, and we bought it new from Maytronics. I would love to see how the bearings are installed in the wheels and the active brush. Thanks.

[@mannycancel120]

Mine works in Manual Mode but when i run it in Auto it runs for a few feet and then stops. I did the upside down test and it runs and then stops like its suppose to. What can be the problem?

[@Dentinvent]

Do you have the motor out ? If it runs with motor in the water but still stops, it will most likely be the drive bearing of the motor . Let me know and I’ll guide you .

[@Dentinvent]

Do you have the motor out ? If it runs with motor in the water but still stops, it will most likely be the drive bearing of the motor . Let me know and I’ll guide you .

[@mannycancel120]

@@Dentinvent thank you. Ill check it out tmw. I appreciate it.