Fix Overheat Issue on Video Transmitter – TS5828

The fact that VTX nowadays are getting smaller, it means there is less surface area to let the heat go and often cause overheat issues. This is especially the case with high power units like the TS5828 600mW. In this post we will share some tips how you can prevent VTX overheat. Same principle should applies to other VTX and electronics.

This tutorial is created by Dronebirth.

Video transmitter overheats

When I first received my TS5828 (a tiny yet high power VTX), I powered it up with a 3S battery, so it was no more than 12.6V. Even though it’s rated up to 24V, only after a few minutes of use, the transmitter was getting so hot it almost burned my fingers. (Antenna was connected).

I measured the temperature with a digital thermometer and it showed 90 degree Celsius, OMG! I cannot imagine what would happen if we run 24V on it as the excessive voltage will turn into heat.

I thought it was a faulty unit, but after some research on forums and reviews, I found out that the overheat issue is happening not only to mine but almost every unit.

Why is overheat bad?

  • Your VTX can burn out during FPV flights and cause crashes
  • Running at this high temperature while in contact with other electronics in your aircraft could damage them
  • It affects your range and transmitter efficiency as they depend on the working temperature

Solution to Fix your VTX Overheat

We can’t reduce the heat VTX generated without changing the design of the VTX or lowering the power, but there are a few easy and cost effective ways to improve heat dissipation.

Better Heatsink

This is the best way to decrease operational temperature. Insert a small heat sink to the transmitter which lets the vtx remain light weight as only add 1-2 grams.

heatsink-overheat-vtx ziptie-overheat-vtx

Steps:

  1. Remove the factory heatshrink from the transmitter
  2. Apply some thermal conductive paste/greese on the VTX
  3. Put the new heatsink on the VTX, and secure by a zip-tie

Lower input voltage

Most VTX has built-in linear voltage regulator, they burn excessive input voltage into heat. To minimize this it’s always a good idea to provide the VTX with the lowest voltage possible (closest to its working voltage).

For example for the TS5828:

  • The lowest input voltage it can take is 7.4V, so if you are running 2S lipo you can just connect your VTX directly to the main battery
  • If you are running 3S, and there is no way you can get anywhere near 7.4V, feeding the VTX with your battery voltage should be fine (max 12.6V), that’s not the end of the world
  • However if you are running 4S, max voltage is 16.8V, and that’s pretty high for the VTX. I would recommend converting the voltage down to 12V for the VTX. Most PDB these days provides 12V and 5V outputs so it’s not hard to find

Good airflow

Decent airflow has significant cooling effect on your electronics, try to place the transmitter in a position with maximum airflow. This is the same principle when talking about where to mount your ESC’s.

mini quad airflow tall standoffs

The rule of thumb is that you never place your VTX too close to any other components which also generate heat without good airflow.

To get best result you should consider all 3 options above. These techniques can be applied not only in the case of the TS5828 video transmitter, but any other electronics devices.

Other causes of overheat?

Please be aware that there are many other issues that can also cause your VTX to overheat. It’s always a good idea to check the below as well.

No Antenna?

Never ever power on your VTX without antenna, all the energy sent to the antenna will bounce right back when the antenna is absent, and instantly cause overheat and might permanently damage your video transmitter.

Wrong antenna connector type

Always make sure that you are using the right connectors between the VTX and antenna. For example the TS5828 is sold with both RP-SMA and SMA connectors.

vtx antenna connector sma rpsma

It does not matter which one you bought however you need to buy the antenna with the correct connector for that. The reason is that some connectors have a pin inside, and the matching connector should have a hole inside. But if you accidentally used 2 connectors with holes, the antenna and VTX are actually not connected, as if you are not running an antenna at all.

Bad/damaged VTX antenna

The VTX antenna can be tuned to a certain frequency, and if you are broadcasting at that tuned frequency your VTX should run cooler. But unless your antenna is really that bad, this normally shouldn’t be a huge difference.

Another problem with antenna could be the bad/broken solder joints in the antenna, resulted from poor quality manufacturing or crashes.

Author : Dronebirth
Editor: Oscar Liang
Join us as a guest writer and help move the hobby forward.
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11 thoughts on “Fix Overheat Issue on Video Transmitter – TS5828

  1. Qdiw

    I just get one of this vtx,
    I open the shrink wrap and the shield
    Ran ot for 1 minute or so, I found that the hottest component is the switching Vreg chip and the inductor not the PA or RF chip

    Reply
  2. Jason Rouse

    I fly in Dubai in the summer and it can get to 110-120F. Probably no wonder I’ve been through a few VTXs this summer. What is the hottest outside air temp you would fly in with a 600mw vtx.

    Reply
  3. Greg M

    Ozzymuppet is correct. Heat is generated by current. For the same power, we can increase the voltage…within limits of the compoents…and reduce the current, all else being equal, there will be less heat generated. Lowering the voltage as stated in an earlier post will do the opposite, if the power source is able to deliver the required current.

    I got here on a search for overheating on my Immersion RC 600mw VTX. I took it apart…separated the metal RF shield from the PCB. What I found was troubling, there is actually an air gap between the transmitter IC and the inside bottom of the metal sheld. So while the metal shield does get hot, consider that heat is jumping an air gap so the IC must be ***really*** hot. So merely attaching a heat sink the metal sheld is problematic.
    While I have no data on the heat tolerance of the unit, I am convinced the excess heat shortens the life of the unit.

    I am going to post some photos and my solution over on Intofpv.com, username is gpilot.

    Reply
  4. Matt

    would it be feasible to use the balance lead and only connect to 2 of the cells? The current draw is so low it shouldn’t damage the battery, provided it is always balance charged…

    Reply
  5. Slawek

    Hi Oscar.
    I don’t see any VTX with linear voltage regulators. This TS5828 and others rated higher than 12V has switching regulators.
    So if this switching power supply is good designed it should work fine with 4S battery.
    Also there is one good option for better heat dissipation. You can add thermally conductive pad betwen components on PCB and metal case on VTX and then add external heatsink. But this require some solder skills.

    Reply
  6. MG

    This post was simply more than useful! I’m waiting one of those TS5828s to arrive and it just saved me time and definitely some pain, since I wanted to simply plug it and run. Thx!

    MG

    Reply
  7. mick

    Tried a 4S battery? In theory it’s the power that generates heat. And the power should be the same no matter what voltage you give it. Lower voltage=higher current to provide a given power level. Of course the is some dropout voltage coming from a voltage reg maybe. But it should be the same

    Reply

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