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Alientech PRO 5.8G Performance Degradation and Finally Failure (Thermal Problem at First)

Thai Voyager

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A long post coming up, but if you're having the same problem as me, it will be an interesting read, in which case, I'd like to hear your experience with this issue.

I'm an electronics engineer with a lot of experience in soldering and trouble-shooting. Bought a brand new Alientech PRO 5.8G, the R/C mod went flawlessly, and I was impressed with the improvement in range on my Mavic Air. After about 6 months (only about 20 flights with the Alientech), I started getting strange behavior during flights. At first, the record on/off button-push on the controller would sometimes fail to register at the drone. Eventually, the flight controls became erratic and sometimes even unresponsive! During this time the controller would start throwing "Weak Signal" and "Disconnected" errors one after another, even though the drone was only about 20 meters away.

This problem did not begin suddenly, but rather it got worse as the flight progressed. At first, the problem would start a few minutes into the flight. Landing and letting the Alientech cool down would solve the problem, only to have it return again after a few minutes into the next flight. Over the course of a few weeks, the problem appearrd progressively sooner and sooner after powering on the Alientech, until it got to the point where the problem started just a few seconds after power-on. Turning off the Alientech during flight would immediately solve the problem, full control of the drone regained. I can safely conclude that the problem is with the Alientech, problem gets worse as the Alientech's temperature rises, and is a result of some some component(s) having gone through a degradation process as indicated by the fact that after the problem developed, it got progressively worse over time as opposed to happening suddenly.

I was able to get a warrantee replacement from Alientech, new unit worked perfectly, but after only about 3 months this time (≈15 flights), it started to show the initial symptoms of the first unit. Over the following weeks the problem gradually got worse, same as with the first unit. Finally it got to the point where all sorts of transmission errors occur starting a few seconds after power-up. Now I'm back to flying with omni-directional rubber-duckie antennas, no signal problems at all.

I've searched everywhere online and nobody seems to have this problem. I cannot believe that I'm the only one who has experienced this, given that TWO of my units failed only after a few months use!

I've disassembled the unit and there is a small power supply module just behind the power button. I've bypassed this module and now powering the two RF amplifier boards directly off a benchtop power supply. Preliminary tests indicate the Alientech is working fine. I'm suspecting the power module is oscillating, will have to get an o-scope on it next. Will keep you updated as to my progress. If you've experienced this problem, I'd love to hear from you.
 
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You post was directed to me from a well known forum member, both he and I have the AlienTech 5.8 booster. I’m having issues as well, and will contact my AlienTech distributor to let him test my AlienTech 5.8 booster once I get the chance to send it in.

My issues are little different, different than yours with not effecting the controller features. Instead, all cable connectors are good only the booster doesn’t operate like it should. Weak signal, or no signal at all with poor signal. Only three times, did the booster perform like it should. All other flights, poorly results.

On another note, my AlienTech 2.4 booster with my Autel Evo 2 operates terrific. No issues there, but once I did have a cable connector go bad and that caused poor results. After pinpointing which cable was bad, replaced it and since no issues.

Thanks for sharing, maybe others will chime in and share their experiences good or bad.

Paul
 
You post was directed to me from a well known forum member, both he and I have the AlienTech 5.8 booster. I’m having issues as well, and will contact my AlienTech distributor to let him test my AlienTech 5.8 booster once I get the chance to send it in.

My issues are little different, different than yours with not effecting the controller features. Instead, all cable connectors are good only the booster doesn’t operate like it should. Weak signal, or no signal at all with poor signal. Only three times, did the booster perform like it should. All other flights, poorly results.

On another note, my AlienTech 2.4 booster with my Autel Evo 2 operates terrific. No issues there, but once I did have a cable connector go bad and that caused poor results. After pinpointing which cable was bad, replaced it and since no issues.

Thanks for sharing, maybe others will chime in and share their experiences good or bad.

Paul
Hello Paul,

At the start, my problem was a slightly degraded signal with the booster, but over the ensuing weeks the performance deteriorated to the point where my issue sounds similar to yours. Within a few seconds after powering on the Alientech, I am seeing weak signal, lost signal, and disconnects standing only a few meters away with the drone on the ground.

You mentioned that your booster worked properly three times. Did these three times occur before the problem first appeared, or did it work randomly in between episodes of not working?

Judging from your email, you seem to be an experienced drone pilot and know this already, but worth mentioning again to be sure that set your radio transmission frequency to use only the 5.8G band, as opposed to leaving it on Auto Select.

As I was living in Thailand at the time I purchased my signal booster, I purchased it directly from Alientech, so I don't have a local dealer to support me. Anyway, keep me posted as to what your dealer finds during his testing.

Kind Regards,
Tom
 
Hello Paul,

At the start, my problem was a slightly degraded signal with the booster, but over the ensuing weeks the performance deteriorated to the point where my issue sounds similar to yours. Within a few seconds after powering on the Alientech, I am seeing weak signal, lost signal, and disconnects standing only a few meters away with the drone on the ground.

You mentioned that your booster worked properly three times. Did these three times occur before the problem first appeared, or did it work randomly in between episodes of not working?

Judging from your email, you seem to be an experienced drone pilot and know this already, but worth mentioning again to be sure that set your radio transmission frequency to use only the 5.8G band, as opposed to leaving it on Auto Select.

As I was living in Thailand at the time I purchased my signal booster, I purchased it directly from Alientech, so I don't have a local dealer to support me. Anyway, keep me posted as to what your dealer finds during his testing.

Kind Regards,
Tom
Hello Tom,

My AlienTech 5.8 booster on Skydio 2+ from the get go didn’t perform well, originally one of the two cable connectors was defective. Replaced both to play it safe, and these two replacemen cable connectors were good but the booster was not working and probably never was. Tried numerous times, and out of about 20 or so flight attempts the booster did operate correctly randomly three times. Boy, during these three good flights performance was fantastic.

From using an AlienTech 2.4 with the Evo 2, now with Evo 2 SmartController the 2.4 operates great. The Skydios 2+ AlienTech 5.8 must be defective, ill contact my AlienTech distributor soon and sent it in for testing, and if for some reason the 5.8 booster is defective I’m staring to feel Skydio 2+ controller can’t handle a booster?

Then, flights going forward was terrible I’m starting to feel the 5.8 booster is defective. Since then, I’ve removed the booster went back to stock antennas on Skydio 2+.

Will definitely keep you posted, It’s good to share with others as we can learn from others previous experiences.

Thanks Tom!
Paul
 
A long post coming up, but if you're having the same problem as me, it will be an interesting read, in which case, I'd like to hear your experience with this issue.

I'm an electronics engineer with a lot of experience in soldering and trouble-shooting. Bought a brand new Alientech PRO 5.8G, the R/C mod went flawlessly, and I was impressed with the improvement in range on my Mavic Air. After about 6 months (only about 20 flights with the Alientech), I started getting strange behavior during flights. At first, the record on/off button-push on the controller would sometimes fail to register at the drone. Eventually, the flight controls became erratic and sometimes even unresponsive! During this time the controller would start throwing "Weak Signal" and "Disconnected" errors one after another, even though the drone was only about 20 meters away.

This problem did not begin suddenly, but rather it got worse as the flight progressed. At first, the problem would start a few minutes into the flight. Landing and letting the Alientech cool down would solve the problem, only to have it return again after a few minutes into the next flight. Over the course of a few weeks, the problem appearrd progressively sooner and sooner after powering on the Alientech, until it got to the point where the problem started just a few seconds after power-on. Turning off the Alientech during flight would immediately solve the problem, full control of the drone regained. I can safely conclude that the problem is with the Alientech, problem gets worse as the Alientech's temperature rises, and is a result of some some component(s) having gone through a degradation process as indicated by the fact that after the problem developed, it got progressively worse over time as opposed to happening suddenly.

I was able to get a warrantee replacement from Alientech, new unit worked perfectly, but after only about 3 months this time (≈15 flights), it started to show the initial symptoms of the first unit. Over the following weeks the problem gradually got worse, same as with the first unit. Finally it got to the point where all sorts of transmission errors occur starting a few seconds after power-up. Now I'm back to flying with omni-directional rubber-duckie antennas, no signal problems at all.

I've searched everywhere online and nobody seems to have this problem. I cannot believe that I'm the only one who has experienced this, given that TWO of my units failed only after a few months use!

I've disassembled the unit and there is a small power supply module just behind the power button. I've bypassed this module and now powering the two RF amplifier boards directly off a benchtop power supply. Preliminary tests indicate the Alientech is working fine. I'm suspecting the power module is oscillating, will have to get an o-scope on it next. Will keep you updated as to my progress. If you've experienced this problem, I'd love to hear from you.
Hello, I Bought a amplification system from a old company called Titan and with my Mavic 2 Pro I didn’t get any increase in range so I ended up selling the system and bought a Alien Tech pro 5.8G system and a new modified controller and with the Alien tech I actually lost range with it…. I sent it back to the person I do business with and he said he double checked all the connections and couldn’t find any problems there. I continued to attempt to get the Alientech system working; but finally gave up. I actually still have the controller I modified and the Alientech Amplifier sitting in a drawer and stopped worrying about it after I kept sending it top the guy I bought it off of and he would just send it back saying it was working…. Tried to get it refunded and he refused. I kinda assumed it was the DJI OcuSync 2.0 maybe wasn’t compatible because I had the Mavic Pro Platinum back in the day and the amplifiers worked great on that drone. I still like to know why that Amplifier won’t increase my range any…..
 
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Hi, how can i disassemble the alientech antenna? Can you take some pictures? My antenna has defects on the power button in your opinion is it possible to change the button and put a different one? I also wanted to ask you how it is possible to replace the power supply from battery to power supply. Do you think it is possible to make a direct connection so that the antenna turns on when the power supply is turned on without having to press the button?
 
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Hello, I Bought a amplification system from a old company called Titan and with my Mavic 2 Pro I didn’t get any increase in range so I ended up selling the system and bought a Alien Tech pro 5.8G system and a new modified controller and with the Alien tech I actually lost range with it…. I sent it back to the person I do business with and he said he double checked all the connections and couldn’t find any problems there. I continued to attempt to get the Alientech system working; but finally gave up. I actually still have the controller I modified and the Alientech Amplifier sitting in a drawer and stopped worrying about it after I kept sending it top the guy I bought it off of and he would just send it back saying it was working…. Tried to get it refunded and he refused. I kinda assumed it was the DJI OcuSync 2.0 maybe wasn’t compatible because I had the Mavic Pro Platinum back in the day and the amplifiers worked great on that drone. I still like to know why that Amplifier won’t increase my range any…..
Hello RawRock,

As I mentioned, my range doubled using the Alientech, before it started to malfunction, so I can vouch for it. Did you set your transmitter to use the 5.8GHz range? The 5.8GHz Alientech will not amplify a 2.4GHz signal, even worse, it will block the signal from the controller from passing through it, so effectively you'll have the equivalent of a controller with no antennas.
 
Hello Tom,

My AlienTech 5.8 booster on Skydio 2+ from the get go didn’t perform well, originally one of the two cable connectors was defective. Replaced both to play it safe, and these two replacemen cable connectors were good but the booster was not working and probably never was. Tried numerous times, and out of about 20 or so flight attempts the booster did operate correctly randomly three times. Boy, during these three good flights performance was fantastic.

From using an AlienTech 2.4 with the Evo 2, now with Evo 2 SmartController the 2.4 operates great. The Skydios 2+ AlienTech 5.8 must be defective, ill contact my AlienTech distributor soon and sent it in for testing, and if for some reason the 5.8 booster is defective I’m staring to feel Skydio 2+ controller can’t handle a booster?

Then, flights going forward was terrible I’m starting to feel the 5.8 booster is defective. Since then, I’ve removed the booster went back to stock antennas on Skydio 2+.

Will definitely keep you posted, It’s good to share with others as we can learn from others previous experiences.

Thanks Tom!
Paul
Hello Paul,
Almost a year gone by and I finally got to poking around the innards of my Alientech with an o-scope and I think I may have found the problem. I found no oscillations in the power module, but I did find what was either a bad solder connection or a faulty zero-ohm resistor. The voltage powering the two amplifier boards was all over the place due to the varying current draw by the amp modules. After my fix, the voltage remained rock-solid at 7.3V, which is actually the voltage of the two batteries in series.

Based on indoor testing, the results look promising, but I don;t want to get over-confident until I've gone outdoors and put some real distance between the controller and the drone. If it passes that test, I'll post a detailed description with photos of my fix. Should happen within a few days, not one year later this time around!

Regards,
Tom
 
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A long post coming up, but if you're having the same problem as me, it will be an interesting read, in which case, I'd like to hear your experience with this issue.

I'm an electronics engineer with a lot of experience in soldering and trouble-shooting. Bought a brand new Alientech PRO 5.8G, the R/C mod went flawlessly, and I was impressed with the improvement in range on my Mavic Air. After about 6 months (only about 20 flights with the Alientech), I started getting strange behavior during flights. At first, the record on/off button-push on the controller would sometimes fail to register at the drone. Eventually, the flight controls became erratic and sometimes even unresponsive! During this time the controller would start throwing "Weak Signal" and "Disconnected" errors one after another, even though the drone was only about 20 meters away.

This problem did not begin suddenly, but rather it got worse as the flight progressed. At first, the problem would start a few minutes into the flight. Landing and letting the Alientech cool down would solve the problem, only to have it return again after a few minutes into the next flight. Over the course of a few weeks, the problem appearrd progressively sooner and sooner after powering on the Alientech, until it got to the point where the problem started just a few seconds after power-on. Turning off the Alientech during flight would immediately solve the problem, full control of the drone regained. I can safely conclude that the problem is with the Alientech, problem gets worse as the Alientech's temperature rises, and is a result of some some component(s) having gone through a degradation process as indicated by the fact that after the problem developed, it got progressively worse over time as opposed to happening suddenly.

I was able to get a warrantee replacement from Alientech, new unit worked perfectly, but after only about 3 months this time (≈15 flights), it started to show the initial symptoms of the first unit. Over the following weeks the problem gradually got worse, same as with the first unit. Finally it got to the point where all sorts of transmission errors occur starting a few seconds after power-up. Now I'm back to flying with omni-directional rubber-duckie antennas, no signal problems at all.

I've searched everywhere online and nobody seems to have this problem. I cannot believe that I'm the only one who has experienced this, given that TWO of my units failed only after a few months use!

I've disassembled the unit and there is a small power supply module just behind the power button. I've bypassed this module and now powering the two RF amplifier boards directly off a benchtop power supply. Preliminary tests indicate the Alientech is working fine. I'm suspecting the power module is oscillating, will have to get an o-scope on it next. Will keep you updated as to my progress. If you've experienced this problem, I'd love to hear from you.

FOUND THE PROBLEM AND REPAIRED IT!!!!
*** See my original post for a detailed description of the failure. ***

I disassembled the Alientech and found that it contains a power supply module which powers two RF amplifiers. Removing the power supply module and powering the two amplifiers directly from an external DC power supply (7.3 volts), the Alientech was working fine, even after running it for several minutes until it got hot. For testing purposes, I had my Mavic Air at the other end of the house, propellers removed, and Alientech connected to RC. I tried various commands such as camera record on/off, motors on/off, gimbal tilt, etc. Solid signal, no signal loss, no errors, no lag in responding to the commands from the RC unit.

I will not give instructions how to disassemble the Alientech, you can find these on other forums, rather I'll explain the process I followed to find the problem and how I fixed it. Now that I knew the problem was with the power supply module, it was time to fix it! Took an oscilloscope to the output, no oscillations, but noticed that the voltage was erratic. The power drain by the amplifier modules is not constant, it varies wildly in proportion with the data rate sent out by the RC unit. To get the transmissions happening, I had to connect the RC unit to the Alientech AND fire up the drone (props removed). This is when I noticed the voltage out of the power supply module was varying in proportion to the demand from the RF amp modules. It was varying between 3v and 7.3v, so definitely something very wrong here !!!

I was able to make some sense of the circuit by following traces on the PCB: Basically, we have a soft on-off switch with a battery level indicator (the green LEDS) and a transistor or two to switch the battery directly over to the two RF amplifier modules. After some poking around, I traced the voltage drop to a resistor labeled R18 on the back of the power supply module. The resistor does not look like other resistors on the board, as it is wider, and instead of having the resistance value printed on it, it has the letters "JD" in copper color. I'm confident it is a Zero-Ohm resister, in other words, a "jumper". I unsoldered it and replaced it with a piece of braided solder wick. I could have soldered the wick over top of it but decided to remove it solely for aesthetics.

I found another on of these "JD" things on the top (component side) of the board. It's labeled R20 and putting an ohm meter across it measured zero ohms, confirming that this component is indeed just a jumper. Although this one had no voltage drop across it, I replaced it with solder wick in case it failed in the future. If you don’t have solder wick, you can use wire instead, but it should be large enough to handle a few amps of current.

Reconnected the RF amp modules to the power supply board, fired up the Alientech with the RC unit connected, drone powered, and this time the voltage remained rock steady at around 7.3v. Put the entire Alientech back together and have been flying fine since. See attached photos of the repair process.

Hope my experience helps you out if you were unlucky enough to get a defective unit like I did!
 

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