Balboa EL2001 Mach 3 Board Information

[caldog20]

Hi,

I have a Balboa EL2001 Mach 3 board that is immediately displaying an OHH flashing code. It has the same behavior whether topside is connected or disconnected. I have done some research and came to the conclusion it is more than likely a bad component on the board. I have done some testing and possibly found a bad diode but it has no markings for identification. I can't order replacements to repair without proper identification of the bad components. Does anyone have detailed schematics or information on these boards?

 

The diode at D7 seems to be bad but it has either gotten too hot and the markings are gone, or just faded.

 

[cranbiz]

I see a heater relay that looks suspect. If the relay is shorted, that can easily cause an overheat situation.

Relays are around $15 each. I would test the 2 heater relays and replace them if bad.

[caldog20]

1 hour ago, cranbiz said:

I see a heater relay that looks suspect. If the relay is shorted, that can easily cause an overheat situation.

Relays are around $15 each. I would test the 2 heater relays and replace them if bad.

I tested them and each tested okay. Are you talking about the black line on the heater relay? That is a shadow from the picture. From what I understand the heater relay being shorted won't immediately throw an OHH code immediately on bootup?

[caldog20]

One thing I did notice is that even though it consistently blinks OHH, if I short the sensor leads on it displays SnA or SnB depending on which one I short. I checked each sensor and they are reading proper resistance based on water temperature. So it seems the logic is working to some extent for the sensor readings. 

[caldog20]

I think I may have found the failure point. It looks like this area got extremely hot at some point. The resistors here look fried and possibly the 2 diodes.

[caldog20]

D3 is a burnt diode for sure. If it had markings on it I could identify it's voltage at least for replacement. 

 

Edit:

 

Found markings after cleaning with ~pure Isoprop. D3 is a 13V Zenner Diode and D7 is a 10V Zenner Diode. I am going to go ahead and replace both. I will update if that fixes the problem.

 

 

Edited June 7, 2023 by caldog20
Identified components

[Michael H]

Ok this sounds promising as I have a EL2000 M3 in my Maax 461 Hot Tub that also just got stuck on OHH. There doesn’t seem to be a reason for this code to not reset so I will look at my board in the above locations. 

I will report back my findings tonight

Thanks

Michael

[Michael H]

I see the area on the board with D3 and D7 and provided the image below

[Michael H]

I see the area on the board with D3 and D7 and provided the some better images below

[caldog20]

2 hours ago, Michael H said:

I see the area on the board with D3 and D7 and provided the some better images below

I had to put an LED flashlight under the board to actually see how hot it got. From looking at D3 and the colorization, it looks like it got hot. Also the trace between D7 and R32 is darker, same as mine, probably due to overcurrent in that area. 

You can see on your board D7 has taken some damage. I am replacing D7 and D3 on my board. I also checked the 2 resistors that were darkened but they both checkout out at 150 ohms which matches their code. This area must have something to do with the sensor circuit for readings/comparisons between the sensors for checking for flow.

If you look on the back of the board in that area, you will probably see where D3 got really hot and made a square mark due to heat on the board. 

 

I have read this can be caused by a stuck heater relay, causing resistance in the temperature sensors to drastically reduce, which can cause overcurrent in the sensor circuit when the temperature stays too hot for too long. Might be a good idea to verify heater relays as well.

[caldog20]

Once my parts come in and I replace the diodes I will report back with my results in case anyone else has the same issue. No disrespect to the board repair people out there, but I prefer to fix these things myself if possible.

[cranbiz]

Why would anyone take offense? The whole premise of this board is to help each other fix their tubs. Some people have the ability to fully DIY, some don't.

Go for it and let us know how you make out.

[Michael H]

Thanks for posting this information as I now understand why my board stopped working correctly and that a board repair might be possible. 

I will do some testing of the board today if I get a chance to determine the faults  

I have also started to look at replacing the whole spa pack with a BP7 5.5kW and a TP700 which can then be connected to remote access with the wifi adaptor. 

[caldog20]

I just wanted to report back with my results. I replaced 13V Zenner Diode D3 and 10V Zenner Diode D7, and the problem has been resolved. The board is working properly now, reporting proper temperatures, and toggling the heater on/off at set temperature. 

 

Thanks,

Caleb

[Michael H]

This is great news and I wonder how I could repair mine. My neighbour is electronically handy so he might be able to help. How and where did you get the diodes so quickly?

I tested my diodes and D3 is gone and D7 partially so I could use your help to attempt my repair in Windsor, Ontario. 

Do you have a repair picture th share?

Thanks Michael

[caldog20]

1 hour ago, Michael H said:

This is great news and I wonder how I could repair mine. My neighbour is electronically handy so he might be able to help. How and where did you get the diodes so quickly?

I tested my diodes and D3 is gone and D7 partially so I could use your help to attempt my repair in Windsor, Ontario. 

Do you have a repair picture th share?

Thanks Michael

When I get back home I can give you exact links from Digikey to order parts. As far as picture it really looks no different. Just unsoldered old diodes, cleaned pads, resoldered new diodes and done. 

[Michael H]

Ok I’ll search for Digikey to see if I can source D3 & D7

[Michael H]

I did some searching but I’m not familiar with sites and the components being listed. If you can provide links then I’ll see if mouser.ca has them which I might be able to get on Monday

[caldog20]

16 hours ago, Michael H said:

I did some searching but I’m not familiar with sites and the components being listed. If you can provide links then I’ll see if mouser.ca has them which I might be able to get on Monday

13V Zenner Diode - https://www.digikey.com/en/products/detail/diodes-incorporated/BZX84C13-7-F/775729

10V Zenner Diode - https://www.digikey.com/en/products/detail/good-ark-semiconductor/BZX84C10/18648842

[Michael H]

Thanks for the links to the replacement diodes and I will order these for my repair and hopefully the board will be functioning soon. 
I will report back on my repair and testing once I receive the parts provided in the link above. 
 

Thanks Michael 

[Michael H]

Expecting to get the Diodes today to do my repair this weekend and then return the my board to the Cottage Hot Tub next week for testing. I will report back in a couple of weeks

[mojonotworking]

Hi, I have this same issue on a GL2000 M3 board, immediately displays OHH on boot, then after 5min everything turns on full, pumps jets and blower! Had some intermittent OH problems before this, caused by the main pump motor stalling, sorted with a couple of new capacitors on the motor. temp probes measure the right resistance.

looking at the board it appears there are some similarities and some differences with the GL2000 vs the EL2000, I have found D3 and D7 but they are further apart on my board see photos below. Defiantly looks like some evidence of over heating on D7 but not sure about D3. D7 and D3 are both the Z9W diodes which is the 10v one I think. Also some evidence of heat at Z11 which is a circuit protection diode I believe.

 

 

 

I have ordered some replacements and I’ll let you know how I get on

@Michael H did the diodes fix your problem on the EL2001 board?

[MilkManPower]

I have a Balboa Mach 2 EL2000. I found the jumper wire between the 2 relays on HTR1 cooked themselves and 1 of the relays. I ordered 3 new Zettler AZ2120-1A-15DF relays and replaced both the HTR1 and HTR2 relays. While at it, I examined the board and noticed a dark spot at D3 on my board. (Searching D3 lead me here) The neighboring D7 looks okay. I'm not sure if the 2 issues are even related.

Both D3 and D7 read about 0.7 volts in diode mode while in circuit forward-biased. Both read close to 2 volts reverse-biased. But I think that's because it's in circuit? The neighboring 5 18A resistors all tested okay at 150 ohms.

I replaced the relays and my hot tub is working again. I did order both the D3 and D7 diodes but I'll save them if the hot tub starts showing the OHH error. I've attached a picture showing the name of my D3 and D7 chips. (Y3 and Z9)