Joe4488 Posted October 20, 2022 Report Share Posted October 20, 2022 Hot tub is equipped with a Balboa ms501 board. Motor will not shut off when selecting high speed there is a loud noise and then motor will shut off after pause starts back up on low speed. Read the topic of bad relay so pulled the board and used 9 volt battery to trip relays with ohm meter across switched pins and when tripped I do get tone when released tone stops. Did this test on both the big and small relays. My question is could it still be relay stuck issue? Could top side control cause relay to have constant power if so how do you test that signal? Is there a test for whatever(if I am tracing correctly looks like a small chip?)sends the voltage to the coil to see if that is continuously sending power and bad? Quote Link to comment Share on other sites More sharing options...
Joe4488 Posted October 20, 2022 Author Report Share Posted October 20, 2022 Additional info that might be pertinent. The water is heating fine but 2 of the 3 heater relays(K1 & K5) measure 76 ohms at the coil and all the other large relays on the board measure in the 150 ohm range. Maybe could cause motor to continue, if so would this also cause the can’t switch to high speed issue? Pump 2 is single speed on a separate board all works fine. Pump 1 when connected to pump 2 connection works fine on high speed. Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted October 20, 2022 Report Share Posted October 20, 2022 Sounds like a stuck relay and it's sending power to both speeds at the same time causing the hard buzzing sound 1 Quote Link to comment Share on other sites More sharing options...
Joe4488 Posted February 9 Author Report Share Posted February 9 Wanted to give a follow up for anyone who might deal with this in the future. It was a relay issue, the smaller one K4. While I was at it I just replaced them all K4 and K2 style, bought on Amazon for around $10 each. I replaced all K2 style both motor and heater while doing it. The replacement is not hard but you do need a soldering iron that gets real hot, originally I tried with my small butane iron and it wouldn’t get the factory solder melting enough so I took to my friend with a better tool and it took about 45 minutes to complete. In regards to the issue of me testing the relay on the bench and functioning correctly prior to the repair, I then reconnected board back to tub and everything worked fine for a week and then same issue so I tested relay right then while issue just happened and sure enough relay showed stuck and once removed and sat on bench for awhile tested good again. So my conclusion was/is when relay would get hot it would stick and once it cooled it would release. Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted February 9 Report Share Posted February 9 6 hours ago, Joe4488 said: then same issue so I tested relay right then while issue just happened and sure enough relay showed stuck and once removed and sat on bench for awhile tested good again. So my conclusion was/is when relay would get hot it would stick and once it cooled it would release. Pump or heater relay? Not sure why there would be excessive heat at the relay. Something odd here. I've been a tech for 25 years and still send them out for repair. Lucky to have a guy that is local and does great work at a reasonable price. Quote Link to comment Share on other sites More sharing options...
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