Getting to the brain- unit works but shuts off prematurely? Come read this!

by Dom Landowski
(Santa Clarita, CA)

So like many of you I purchased a Dolphin to clean my pool because I am lazy, it does a better job than I ever could, and it reduces the strain on my pump and main filter which in turn saves me a load of money by looking at the comparison of power consumption on the pump vs the unit.

So, you are here reading this because you stumbled upon the topic and noticed your unit is turning off anywhere from 1 min to anything after an hour even.

"Why is this the case?" you have asked yourself.... simple, much like many others on here, there is a good chance that over the years the motors have degraded and now draw a bit too much power causing the CPU to think the bag is full or go into protect and shutdown.

So now you must be thinking "How do I fix it?"

Also simple if you are semi-mechanically inclined, if you are not and have not taken something basic apart or have no patience, then stop now before you cause a mess or potentially hurt yourself.

For those of you willing to take the chance continue reading...

You will do the following:

1.) Always check that your power supply is in fact functioning by using the test on here.

2.) Since you know the power supply is good and you are not using any extension cords to power the unit, always insuring you have a good ground on your outlet, you will now unplug the unit from its power supply (after it is unplugged for about 10 seconds allowing any potential residual power to dissipate). You may leave the switch in the on position.

3.) Start to disassemble the unit. This is the P.I.T.A. part and small hands are almost necessary here. I recommend having plastic bags and a sharpie next to you so you can place the parts in a bag and not get them mixed up because some screws are longer than others. it is also advisable to use a power tool like a drill with a Philips attachment to make this process go faster.

- to disassemble the unit, be on a large flat surface so nothing like screws can go rolling under places and get lost in the infinite abyss that is tool cabinets and such. There are 14 plastic screws in total (6 on each side of the dolphin, which is split again in 3 on each side of the "brain box") and 2 that hold the plastic cage over the "brain box." Removing these two first is advised.

4.) next flip the unit onto its side and remove the gren panels by first unscrewing both bolts that hold the float handle to the unit. Then use a wide but small flat head to gently, and I mean gently work around it and separate them from the main housing that is yellow and pinkish purple.

5.) once you've done this you can remove the rollers and belts. Be careful with the side that has the drive motor on it, there is a gear that can slip out that connects the motor to the drive bearing.

6.) on each side of the main housing there are two bolts that hold the brain unit in. While the unit is upside down, remove all 4 bolts and store as you have (or should have) been doing.

7.) there are now two tiny screws holding the cable to the inside of the housing, this is the cable strain relief.

remove and pull the plastic yellow piece out and again store it.

8.) start to pull some of the cable through the side hole so you can pull the brain box out.

9.) after pulling about a foot of this cable out, you can pull the brain unit out and flip it right side up.

10.) begin to remove and store all the bolts and nuts (they can fall out so be careful here) to gain access to the brain unit.

11.) using two thin (not very wide) but thick; hope that makes some sense, flat heads place them into the side tabs to help you pull the cover off.

12.) you should now be in the motor/brain compartment. Gently tug on the power wires and use the sharpie to label which power wire goes where. This is where some of the more technical stuff comes into play. I would not recommend opening the motors up if you have never done so, on the power tabs are spring loaded 'brushes' made of graphite that supply and lubricate the motor with power. If you think you are up for it, I do recommend getting some q tips and denatured alcohol to clean out the dust that is in here and prolong the life of the motor.

YOU MAY CHOOSE TO SKIP OPENING THE MOTORS- again it is a bit hard to do, especially if you have no clue what to expect or are doing.

13.) Next, most of these units again shut down due to over-current/voltage issues caused by the buildup of the brushes in the motor. So cleaning them helps but ultimately you will need to add a 1/4 watt 10 ohm resistor to effectively trick the brain or CPU/micro-processor here to think the motors are taking 10% less power than they are. We are going to trick the circuitry that looks at this power consumption/draw and tell it that its doing good. Every unit has a very slim threshold that allows the unit to continue to operate.

You will add in parallel, NOT SERIES, this new 1 ohm resistor, and you will just solder it in series to the giant blue existing one that is right next to the impeller motor that you have on the lid of the brain box.

Additionally since your soldering iron is hot and you probably have a pair of wire cutters/strippers handy, check to make sure the cheapy white plastic connectors for this impeller motor are not showing a dark spot on them. Mine had what looked like Arc marks due to someone or something crimping over the wire insulation and not the bare wire causing some continuity problems or the motor drawing too much current and getting hot. I want to say some of these units may have had blown motors due to this.

14.) grab a drink, and do everything in reverse order to re-assemble the unit. Making sure no sand or anything got into the Brain box Gasket Groove. It is highly recommended you have some O-ring grease handy and apply a thin and semi-conservative coat onto the o-ring after cleaning to keep it water-tight and prevent it from rolling/pinching during assembly that can cause leaks.

Like wise if you are super scared of leaks, just get some RTV or Silicone that is pliable when dry and apply some to the crack where the two parts of the brain box separate.

16.) during re-assembly I recommend getting some marine grease and some latex gloves to re-grease the bearings as well as some plastic components that you will see have been rubbing and apply again semi-conservatively but spreading a thin coat everywhere as well as doing your best to pack the bearings.

17.) plug it in after it has been assembled, cross your fingers and it should all be perfect after that.

Viola, thanks for reading this term paper of semi-detailed repair instructions, sorry there are no pics, I was covered in grease and in too much of a panic that my investment was gone just like that to think I would ever write a tip or take pics.

Enjoy =)

also supposedly sells boards for CHEAP for our units. So if yours has corruption of physical damage then give them a try. I am working on seeing if we can get a motor connect as I have some friends in the UK and Germany as the motor manufacturer is a German company.

Also my unit stopped doing a full cycle one day after months of good service to me and my pool. It wasn't until I was looking for spare parts that I stumbled upon this wonderful community.

Cheers to all of you I hope for your sakes that this was helpful and worked as a fix for you.

Also I take no responsibility if you messed something up and got lost. This is meant to serve as a guide and you take full responsibility for trying to do any work on your unit.

-Dom Landowski
Santa Clarita, CA

Comments for Getting to the brain- unit works but shuts off prematurely? Come read this!

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Apr 21, 2017
Dolphin m5
by: Anonymous

Hi Dom, if your still there i would like to get some pictures of your modified board. I have this dolphin that has quit working four times in 2.5 years and they want $1800 for the "motor" which they say is bad.

Apr 22, 2016
by: Anonymous

I have spent the past few days playing with a control board I have some major issues with. No matter what the darn thing continues to just do a test cycle. I built a test bench and have a tub with the pump installed so I can run it as long as I want...

Looking at the unit opened up, once again I need to reaffirm I was correct the first time... Use a 1 ohm resistor, not a 10 ohm. The main resistor is a .2 ohm 2w resistor... However in my case even dropping to a .5 ohm in parallel has done absolutely nothing to solve this dilemma. I am going to do further research as well as testing to see if there may be an issues with the software and or board.

Oct 07, 2015
by: Dom Lando

There is a typo in my original post. Resistor should be 10 ohms not 1 ohm. Sorry***

ADMIN: I changed 1 to 10 in the original post.

Oct 07, 2015
Not a 1 ohm
by: Dom Lando

You should not have used a 1 ohm 1/4w resistor.

I recommend swapping it for a 10ohm 1/2w or better watt resistor. 1 ohm would only change the current draw the sensor sees by 1%, a 10 ohm does a 10% drop, and 100ohm would be overkill.

Try replacing it with a 10 ohm resistor (between 10 and 16 ohms is fine) and let me know. Last thing to do is use compressed air on the board, micro particulates can get on and cause the boards to do weird things. If that all fails, most likely you either have a failing motor or power supply. Just because the power supply voltage is present, does NOT mean the current is there to supply it. I use an independent power supply with and ammeter in series to check. Current draw should not exceed 3-4 amps when running. It will peak at 5amps MAX!

Most likely though, the motor has too much brush dust and is sagging the input current and arcing inside.

Otherwise a bad transformer coil, rectifier, or capacitor bank is the part of the PSU that failed.

Oct 06, 2015
resistor made no difference
by: Anonymous

I just did your sugestion and soldered a 1/4 watt 1ohm resistor in parrellel right beside the old old one and the same reuslts. I have two of these machines and love them when they work right but this is toooooo much Anymore sugestion.s?

Aug 12, 2015
Update! @Diego
by: Dom Lando

Got another one just to mess around with; seeing as how it was only $50 on craigslist with no power supply,

Cool thing was I fixed it! So now I've got a working unit, at least so far. If you need pics I can supply you with some. At least up until I put it back together, but I am going to try and 'copy' the programming from my now working now unit onto the one that got water on the pcb.

So let me know what you need Diego. I've mapped out most of the PCB and taken enough pics to get part numbers off of any component

Jul 29, 2015
by: Dom Lando

I took a really bad one, in the heat of the moment and my hands all greasy covered in silicon I did not really take any.

Jun 16, 2015
Help request
by: Diego

Don't you have a picture of your update?
I have a problem with my Dolphin Diagnostic, a burned resistor, but I cannot see its resistance value (OHM).
I would appreciate your help, my email address is
Many thanks
My best

Jun 13, 2015
by: D Landowski

You should re-seal the brain box with silicon, the o ring will leak. I learned that the hard way.

Also, the website I listed does not sell boards anymore :/ if anyone has a connect please let me know.

Jun 07, 2015
No problem
by: Dom Landowski

No problem :) I will post a new article about the motors if I get anywhere and can source some.

I am looking into getting an empty brain box or a one with bad internals to see if we can swap them out for something else, I've messed with these mentors in the past and my father is a retired electrical engineer that has some connections to companies that may have just what we are looking for :)

Jun 07, 2015
Excellent Instruction

Thank you for taking time to write a great informative article!

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