Hayward AquaTrol - No display, leds or power to pump

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M

MBXDroid

0
Jul 9, 2014
9
Fishkill,NY
So yesterday I went to clean the pool and I noticed neither the pump nor the swg were working. After the usual checks, I determined it was the swg since I was able to bypass it and plug my pump directly to the main timer switch. I ran through the troubleshooting and everything checked out okay until I get to step H ( If pins are good, check for 3 to 5 volts (DC) on pins 2 & 4, starting from the left). I'm not reading any power to the display board.

After reading multiple threads here and around the net, I see that the thermistor is usually the main problem. Thing is, in pretty much all those cases, the display still worked. Also I have the MF73T-1 2/18 thermistor which if I read correctly is one of the better ones, so I'm not exactly sure if that is the issue. My thoughts were to replace the thermistor and see if that fixes the issue but I can't seem to find it anywhere.

Also it may be worth noting that I don't see any damage to the board. No burn spots, bulged capacitors and even the thermistor looks fine. So now I'm stumped and reaching out to the community. Is this a lost cause? Should I bother to replace the thermistor even though I can't seem to find the exact one? Is my only option to replace the entire main board?

I'm including some pictures of my main board. I can't seem to find this exact model either and maybe someone will see something that I missed or guide me in the right direction.

Thanks in advance!

6e0m7b.jpg


2j0bkg2.jpg


i50q4k.jpg
 
Welcome to TFP :wave:

I don't think the thermistor is the issue since you don't have the 5 volts on pin 4 of the display header. But if you are adventurous, here's how to diagnose a faulty Thermistor on your board for reference. Should you need to replace the thermistor MF73T-1 2/18, the AS32 2R025 (Digi-Key 570-1105-ND) is a better choice and is highly recommended.

Using a multimeter, you should be able to follow the instructions on how to test for the voltage readings as mentioned in Post# 3. If you have zero volts on TP-1 to begin with, then most likely your board have a similar problem as discussed in this thread. Most likely the suspect is a shorted U5 and toasts the U7 (24V reg). As a result, no 5 Volts supply.

I am guessing your Mainboard part# is GLX-PCB-TROL-RJ. Please note, the link is used as an example.

Please let us know if you have any questions.

 
Thanks for the welcome!

Been a long time reader but never really posted anything. Thank you very much for the valuable information. The threads you referenced above were part of the wealth of threads I read before posting, but didn't want to get ahead of myself so I appreciate the guidance. I just ordered a new multimeter as I have an old analog one and want to make sure my readings are accurate when I do all this testing.

Now if my problem is the shorted U5 and toasted U7, then I need to replace both correct? I didn't see the OP from that thread post a final "problem solved" so just would like to confirm.
 
huh… I still have my Simpson 260-8 series analog multimeter that I grew up playing with. I hope you did not use your analog meter lower range continuity test to probe your board. Doing so might potentially cause damage to the onboard chips.

The OP on that thread had either fixed his board or damaged the PCB beyond repair. I hope it’s the former otherwise, he would come back with more questions. Now that you found that thread and pretty much aware of the delicate and tedious soldering work involved.
I guess my questions to you are,
1. are you willing to DIY for whatever reasons,
2. get somebody to fix it for you,
3. or buy a new mainboard?

Should you choose #1, the shortcut is to perform a continuity test using a DVM. Measure the resistance between pin10 of U5 and R15. For reference, it should read 40k-50k ohms with respect to R15 or Negative post. If the resistance measured is almost near zero ohm, carefully nip pin 10 of U5 midway between the package and the PCB. Again, measure the resistance between pin 10 on the package. If the resistance is almost near zero ohm, then you can rest assured U5 is shorted and must be replaced. If that is the case, you can say goodbye to the 24V reg. Make sure the resistance of U7 pin3 solder pad is somewhere between 40k-50k ohms when a known good U5 is in place before you solder a known good 24V reg in place.

Other than that, please measure the voltages on the TP (test point) as mentioned in that thread and ask questions you may have.

Repairing a damaged or broken tiny PCB tracks are more difficult and time-consuming process. So be careful. It would be wiser to install a 16 pin DIP socket for ease of replacing U5 the next time around. 10 pcs of 7824 reg (TO-220) package cost about $1.38 but for time constraint repairs, you may want to source them locally.
 
Definitely didn't use the lower range continuity test. I am more than willing to DIY and really like the idea of the DIP socket.

Did you mean an 18 pin though? Like Digi-Key ED3047-5-ND

As soon as my new multimeter gets here, I'll begin testing and report back my findings.
 
Haha no worries, was just double checking. Now the fun part.....

Testing the 5 points according to the thread you referenced I get some odd results.

TP1) 24 Vdc
TP2) 22-23 Vdc
TP3) 5 Vdc
TP4) 0 Vdc
TP5) 34-35 Vdc

TP2 seems too high yet TP3 is right on. TP4 seems to point to an issue with U13. Then TP5 is way high when I thought it would be 0 since TP4=0.

Hopefully you can make sense of this and let me know what I should do next.
 
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MBXDroid said:
Haha no worries, was just double checking. Now the fun part.....

Testing the 5 points according to the thread you referenced I get some odd results.

TP1) 24 Vdc
TP2) 22-23 Vdc
TP3) 5 Vdc
TP4) 0 Vdc
TP5) 34-35 Vdc

TP2 seems too high yet TP3 is right on. TP4 seems to point to an issue with U13. Then TP5 is way high when I thought it would be 0 since TP4=0.

Hopefully you can make sense of this and let me know what I should do next.
Click to expand...
TP2 voltage reading seems high because TP3 (5V reg) has no load with TP4=0. U13 has an integrated error amp and not likely to turn on if the current demand exceeds the limit or overload. More on U13 and U14 later if needed.

As to the TP5, looks like a test error to me. The original post is pointing to 0 volts. The absolute max VDD of the micro-controller along with the other chips is 5.5 volts. At 35 volts supply to the chips, I expect everything to go up in smoke! If you will put together the two low voltage schematic diagrams from that thread side by side, you will notice that the 30-33 volts feed is split into two separate path and completely independent of each other. You can still have a healthy 5 Vdc supply at the end of the line even without the thermistor in place. The R7 (7.15k ohms) is there to provide feedback for the voltage and current reporting.

Anyway, let’s narrow down the troubleshooting. Disconnect the salt cell cable, flow switch and display board from the mainboard to rule those out. Turn on the power and measure the TP voltage. If the results are the same with the above, turn off the power. Measure the resistance of pin#4 (display header) or TP17 with respect to R15 (negative post).
Please report back.
 
It looks like the thermistor was replaced but the legs were not put through the original holes.

I suspect that the new thermistor legs had a different spacing and a new hole was drilled.

There are two types of thermistor. One type has flat legs that are spaced further apart (AS322R025). The other type has rounded wire legs that are spaced closer together (SL322R025).

DigiKey Electronics - Electronic Components Distributor

The original thermistor was the flat leg type but it was replaced with a round wire leg type.

The wire legs can be spread to fit the holes.

I would suggest replacing the thermistor but make sure to get the legs through the correct holes.
 
JamesW said:
It looks like the thermistor was replaced but the legs were not put through the original holes.

I suspect that the new thermistor legs had a different spacing and a new hole was drilled.

There are two types of thermistor. One type has flat legs that are spaced further apart (AS322R025). The other type has rounded wire legs that are spaced closer together (SL322R025).

DigiKey Electronics - Electronic Components Distributor

The original thermistor was the flat leg type but it was replaced with a round wire leg type.

The wire legs can be spread to fit the holes.

I would suggest replacing the thermistor but make sure to get the legs through the correct holes.
Click to expand...


That is interesting, but the funny thing is that I bought the system new 3 years ago and received it like that. This is the first time that I've had an issue with the system and actually taken it apart to look at the main board.
 

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AFAIK, the aqr thermistor solder pads can accommodate either SL32 or AS32. The through holes are fitted with vias to connect the layers. I am guessing, the solder marks in the picture are indicative of OP's attempt to see if his soldering iron is hot enough to replace the thermistor. Just a fyi my AQR T-15 came with the same thermistor MF73T-1, 2/18 out of the box.

If it were me, I'll fix the 5 Vdc power first and deal with the thermistor later if deemed necessary. The thermistor has nothing to do with the missing 5 volts. But that's my interpretation according to the dwg.



 
In the top picture, you can see where the original holes were. The AS322R025 has a wider stance than the SL322R025. The SL322R025 legs can be bent to fit the holes where the AS322R025 thermistor went.

There is a copper pad under the heat shields. So it is possible to get a connection if you miss the original holes but it's not good practice.

In my opinion, the thermistor has almost definitely been replaced and not properly.

I'm pretty sure that a new thermistor would fix the problem if it is installed correctly.

If the diagnostic voltage was low or fluctuating, then it was probably a bad thermistor.
 
JamesW said:
What were the diagnostic readings before you pulled the board?
Click to expand...

I will recheck them tomorrow as I didn't take notes and can't remember. What I do remember was that everything was within the ranges mentioned in the diagnostics manual until I reached step H. What bugs me about the thermistor, is that it's been working in it's current condition for 3 seasons. Seems odd that an incorrectly installed part would work for that long.

Discombobulated said:
AFAIK, the aqr thermistor solder pads can accommodate either SL32 or AS32. The through holes are fitted with vias to connect the layers. I am guessing, the solder marks in the picture are indicative of OP's attempt to see if his soldering iron is hot enough to replace the thermistor. Just a fyi my AQR T-15 came with the same thermistor MF73T-1, 2/18 out of the box.
Click to expand...

Other than checking voltages and removing the board for pictures, I haven't touched the board at all. Only thing I can think of is that I was either sold a refurb or a return where someone swapped out a new board with a repaired board.
 
Last edited:
Meadow said:
TP2 voltage reading seems high because TP3 (5V reg) has no load with TP4=0. U13 has an integrated error amp and not likely to turn on if the current demand exceeds the limit or overload. More on U13 and U14 later if needed.

As to the TP5, looks like a test error to me. The original post is pointing to 0 volts. The absolute max VDD of the micro-controller along with the other chips is 5.5 volts. At 35 volts supply to the chips, I expect everything to go up in smoke! If you will put together the two low voltage schematic diagrams from that thread side by side, you will notice that the 30-33 volts feed is split into two separate path and completely independent of each other. You can still have a healthy 5 Vdc supply at the end of the line even without the thermistor in place. The R7 (7.15k ohms) is there to provide feedback for the voltage and current reporting.

Anyway, let’s narrow down the troubleshooting. Disconnect the salt cell cable, flow switch and display board from the mainboard to rule those out. Turn on the power and measure the TP voltage. If the results are the same with the above, turn off the power. Measure the resistance of pin#4 (display header) or TP17 with respect to R15 (negative post).
Please report back.
Click to expand...

Okay finally had a chance to remeasure voltages.

TP1) 24.0 Vdc
TP2) 23.2 Vdc
TP3) 5.06 Vdc
TP4) 0 Vdc
TP5) 35.5 mVdc <-- was my error for sure as I didn't notice the "m"

Resistance of Pin4/TP17 to R15 = 18k ohm
 
If you're not getting 3 to 5 volts (DC) on pins 2 & 4, starting from the left, then you probably need a new circuit board. Make sure that you have the tester set to DC and not AC.

I would try the thermistor first to see if that works.
 

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