- Aug 5, 2023
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I am trying to upgrade my AAXA projector by replacing the really noisy fans. The original fans are 50x50x10mm 3-pin 12V fans rated for 0.19A. There are two of them, each with their own 3-pin port (pretty sure they are using micro JST connectors) on the circuit.
My first attempt at this was to replace each of the two fans with a Noctua 60x60x25mm fan (NF-A6x25 FLX). I 3D printed a custom mounting plate for the bigger fans and soldered on the old connectors. Red to red, black to black, and yellow to yellow. Unfortunately, this did not work. The fans would not spin up when I energized the circuit. Then I tested the fans using my power supply, and the fans spun up just fine. So for some reason, the circuit was not accepting of the new fans. The news fans are rated for 0.12A, so they aren't trying to take more power than is available. I did some more testing and found that the original fans start spinning at lower voltages when compared to the Noctua fans, and that is my best guess as to why it wasn't working. Also the original fans are brushless.
Next, I said screw using their ports, I'll use the USB port to power one 120mm Noctua fan. When I removed the old fans entirely and had nothing plugged into their ports, the projector would shut itself off after maybe 30 seconds of being on. I figured this was the circuit not sensing the fan signal, and fearing overheating, the projector would shut itself off. After a second failed attempt, I tried to just put it back the way it was originally by soldering the connectors back to the original fans. Same deal, red to red, black to black, and yellow to yellow. But now, these fans don't spin at all. But weirdly enough, the projector no longer shuts itself off. I tested the fans again using my power supply, and they spun up just fine.
What I did next was use the USB powered 120mm fan to actually cool the projector, and have the two original fans literally dangle outside of the case doing nothing. They don;t spin at all, but somehow they tricked the projector into working. This did work, for a handful of hours, but now the projector is shutting itself off again. I tested the fans again through the connectors, and they both spin when I put 5-12v through. I fear that something may have occurred and now the circuit is no longer sending power (or enough power) to the fan ports, which is why they aren't spinning.
That leaves me where I am now... I have a working projector but the fans are causing all the issues, causing the projector to shut itself off. I just ordered some new 3-pin fans and some micro JST connectors to try those out, but I am doubtful it will work. If not, I don't have many other ideas. By the way, I know for sure that it is the fans causing the issues. The projector has three brightness settings, the lowest of which does not power the fans at all. On this setting, the projector works regardless of the fans being there or not. It is on the brighter modes that fans are needed, and then the projector shuts itself off.
My first plan of action is to try the new fans with new connectors when I get them in the mail. If that doesn't work, then I am wondering if I can trick the circuit by sending a signal to the fan ports. I read a thread about someone trying to disable a fan but was unable to find a way to trick the circuit board. People suggested all sorts of resistor combinations to try and send the right signal, but from what I can see nothing ever worked. But something that apparently does work is to send a signal to the circuit fan port from an entirely different fan. Can I use the signal lead on my 5v fan and wire the signal lead to the fan ports? Or will the circuit know that I am only sending a signal and not drawing power, and continue to shut off the projector? And if I can just send the yellow signal lead to the fan ports from my one 5V fan, can I split the lead and send it to both fan ports, or do I need two fans to send two separate signals?
Another option would be to somehow disable this feature in the software, but I have no clue how to do that or if that is even an option. I have read some other threads about similar situations, and they find that disabling the fan is not an option in the BIOS. But this is for other devices, so I went ahead and reached out to AAXA in the hopes that they may be able to help. Will report back on that if anything happens.
Also if there are any other solutions you may come up with, please let me know. I am not too familiar with this stuff, I am a mechanical engineering student so my electrical knowledge only goes so far. This is also my first post on Tom's Hardware, and I am hopeful that I can get some guidance. I really hope I didn't just trash my working projector.
My first attempt at this was to replace each of the two fans with a Noctua 60x60x25mm fan (NF-A6x25 FLX). I 3D printed a custom mounting plate for the bigger fans and soldered on the old connectors. Red to red, black to black, and yellow to yellow. Unfortunately, this did not work. The fans would not spin up when I energized the circuit. Then I tested the fans using my power supply, and the fans spun up just fine. So for some reason, the circuit was not accepting of the new fans. The news fans are rated for 0.12A, so they aren't trying to take more power than is available. I did some more testing and found that the original fans start spinning at lower voltages when compared to the Noctua fans, and that is my best guess as to why it wasn't working. Also the original fans are brushless.
Next, I said screw using their ports, I'll use the USB port to power one 120mm Noctua fan. When I removed the old fans entirely and had nothing plugged into their ports, the projector would shut itself off after maybe 30 seconds of being on. I figured this was the circuit not sensing the fan signal, and fearing overheating, the projector would shut itself off. After a second failed attempt, I tried to just put it back the way it was originally by soldering the connectors back to the original fans. Same deal, red to red, black to black, and yellow to yellow. But now, these fans don't spin at all. But weirdly enough, the projector no longer shuts itself off. I tested the fans again using my power supply, and they spun up just fine.
What I did next was use the USB powered 120mm fan to actually cool the projector, and have the two original fans literally dangle outside of the case doing nothing. They don;t spin at all, but somehow they tricked the projector into working. This did work, for a handful of hours, but now the projector is shutting itself off again. I tested the fans again through the connectors, and they both spin when I put 5-12v through. I fear that something may have occurred and now the circuit is no longer sending power (or enough power) to the fan ports, which is why they aren't spinning.
That leaves me where I am now... I have a working projector but the fans are causing all the issues, causing the projector to shut itself off. I just ordered some new 3-pin fans and some micro JST connectors to try those out, but I am doubtful it will work. If not, I don't have many other ideas. By the way, I know for sure that it is the fans causing the issues. The projector has three brightness settings, the lowest of which does not power the fans at all. On this setting, the projector works regardless of the fans being there or not. It is on the brighter modes that fans are needed, and then the projector shuts itself off.
My first plan of action is to try the new fans with new connectors when I get them in the mail. If that doesn't work, then I am wondering if I can trick the circuit by sending a signal to the fan ports. I read a thread about someone trying to disable a fan but was unable to find a way to trick the circuit board. People suggested all sorts of resistor combinations to try and send the right signal, but from what I can see nothing ever worked. But something that apparently does work is to send a signal to the circuit fan port from an entirely different fan. Can I use the signal lead on my 5v fan and wire the signal lead to the fan ports? Or will the circuit know that I am only sending a signal and not drawing power, and continue to shut off the projector? And if I can just send the yellow signal lead to the fan ports from my one 5V fan, can I split the lead and send it to both fan ports, or do I need two fans to send two separate signals?
Another option would be to somehow disable this feature in the software, but I have no clue how to do that or if that is even an option. I have read some other threads about similar situations, and they find that disabling the fan is not an option in the BIOS. But this is for other devices, so I went ahead and reached out to AAXA in the hopes that they may be able to help. Will report back on that if anything happens.
Also if there are any other solutions you may come up with, please let me know. I am not too familiar with this stuff, I am a mechanical engineering student so my electrical knowledge only goes so far. This is also my first post on Tom's Hardware, and I am hopeful that I can get some guidance. I really hope I didn't just trash my working projector.
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