Zenfox T3 Triple channel dash cams free test invitation, limited quantity

[EGS]

You must of got a version built specially to test how it copes with being continuously overheated!


Could do with a copper heat spreader on top of the processor to fill most of the gap and just a thin layer of thermal paste either side.

will try to find one of the right thickness.

 

[Nigel]

Bit surprised there wasn't any pink stuff/paste on the SD card slot, as it is there appears to be an air gap to insulate it!

 

[EGS]

Bit surprised there wasn't any pink stuff/paste on the SD card slot, as it is there appears to be an air gap to insulate it!

There was absolutelly nothing on top of the SD card slot/tray. That one could benefit from at least a thermal pad since it has some holes in the surface for the spring tabs. The pink gunk could possibly squeeze inside the tray and that wouldn't be good.

 

[HonestReview]

will try to find one of the right thickness.

Could definitely get a piece of copper, put thermal paste over cpu, and adhere a piece of coper to cpu...then put paste between the copper to the EMI shield. Might help some.

Secondary test is remove the EMI shield and adhere heatsink direct to CPU and see what happens to camera without EMI shield. I wonder how much interference the camera would really get?

 

[jokiin]

Secondary test is remove the EMI shield and adhere heatsink direct to CPU and see what happens to camera without EMI shield. I wonder how much interference the camera would really get?

the heatsink might have the same effect in reducing EMI anyway, sticking it directly to the processor may be an issue for the surrounding components, can't really judge the height of the components from the photos, might get away with covering the surrounds with kapton tape with just the processor exposed, only guessing, can't make it out in the photos to know if that would be ok or not

 

[HonestReview]

the heatsink might have the same effect in reducing EMI anyway, sticking it directly to the processor may be an issue for the surrounding components, can't really judge the height of the components from the photos, might get away with covering the surrounds with kapton tape with just the processor exposed, only guessing, can't make it out in the photos to know if that would be ok or not to see how @EGS's tests go.

All this boils down to options. The current revision seems ill planned. I'm not certain a firmware mod is going to be able to address the overheating. However, if Zenfox doesn't get back on a solution, I guess we can always start experimenting on our own. I am curious

 

[jokiin]

Give them a chance to see what they can come up with before breaking out the tools

 

[HonestReview]

Give them a chance to see what they can come up with before breaking out the tools

I did say IF...Hope he does come back with a solution. If not we've got some fun experimenting ahead!

 

[EGS]

Could definitely get a piece of copper, put thermal paste over cpu, and adhere a piece of coper to cpu...then put paste between the copper to the EMI shield. Might help some.

Secondary test is remove the EMI shield and adhere heatsink direct to CPU and see what happens to camera without EMI shield. I wonder how much interference the camera would really get?

I already had that in mind...

 

[EGS]

All this boils down to options. The current revision seems ill planned. I'm not certain a firmware mod is going to be able to address the overheating. However, if Zenfox doesn't get back on a solution, I guess we can always start experimenting on our own. I am curious

It may or will a combination of the two. Firmware and hardware

 

[HonestReview]

It may or will a combination of the two. Firmware and hardware

It'll be interesting to see if:

A. Firmware update can up temperatures, though if cooling is inadequate, this might not make a whole lot of difference
B. Shuffling around how parts are outlaid in the case. Allowing for the heat sink to sit flush on top of processor without anything in between.
C. Sending us out an updated revised camera to test if design changes are made.

 

[SawMaster]

The heat sink is doing nearly nothing- there's too indirect of a heat-transfer path between it and the CPU. No wonder this thing wilts in the slightest heat. The EMI shield may be necessary (or may not be) but would be OK if a thermal epoxy like Arctic Silver is properly used to attach it to the CPU, then with the heat sink done the same way directly on top of that. It may require a longer cable and it's own shielding but the cable needs to be outside of the whole mess, not sandwiched in between where it is now impairing the heat path. You could even remove a fin or two off the heat sink to make a way for the cable to cross outside and you'd still get far better CPU cooling than this. And in the pics you can see the biggest failing of thermal putty- air pockets and incomplete coverage of the entire area involved. Now you have hot-spots in the CPU which is going to cause malfunctions and early failure. As it is now the EMI shield under the heat sink is doing most of the cooling- maybe almost all of it 😱

The principle of heat-sinking is to provide a larger radiant surface on the cold side while having maximum contact on the heat-generating side. The total amount of cooling available is basically a function of the total surface area on the cold side. This heat sink would work equally well with twice the fins at half the fin height, and given that the heat would then have twice the fins closer to it, the heat would travel to the fins to be dissipated even faster than it is now which would likely even improve the total cooling without any increase in the total surface area. This might even allow the cable to pass over the heat sink at it's current length. And even adding an EMI shield over the cable wouldn't significantly reduce the airflow which does the cooling; in fact if that shield were thermally bonded to the heat sink now you've got even more surface area to dissipate heat from. Even a push-fit cover here would transfer some extra heat and still give good EMI protection.

It's becoming clear to me that neither Zenfox nor whoever designed the heat sinking have a clue about what they're doing or they'd see the very basic mistakes they've made so it's no wonder they can't seem to fix the camera. This has been designed only to make cam assembly as cheap and quick as is possible while having something in there to show and use as an excuse that the cam factory did things the right way when they clearly didn't 👎 If Zenfox gives the slightest damm about his cam he will spend a dollar or two more per cam to get them built right with thermal epoxy and the redesigned cable routing which will then allow this cam to work in the same heat ranges that Thinklware, Garmin, and Blackvue are currently working in successfully.

Otherwise this cam is doomed, which is not how any of us wants the story to end.

Phil

 

[kamkar]

That pink stuff look like a thermal pad, you will see something similar on the memory and voltage parts on a computer GFX card.

 

[Nigel]

It may require a longer cable and it's own shielding but the cable needs to be outside of the whole mess, not sandwiched in between where it is now impairing the heat path.

There is no cable sandwiched under the heatsink, only tape!

Yes, I definitely there is room for improvements in here. Now that I had dissected this unit, I will do some experimenting of my own.

Reducing the amount of pink stuff by replacing most of it with a sheet of copper, or less effective aluminium would help. Preferably larger than the processor to spread the heat quickly out over a wider area than it is at present.

The tape appears to be functional, so don't just remove it, it is needed to block the EMI escaping through the slots in the ends of the EMI shield/off the ribbon cable connectors. It does not need to go under the heatsink though, I have a T3 where it does not. If you modify it, make sure that it does all end up grounded (it is conductive tape), the EMI shield is also grounded.

 

[HonestReview]

The heat sink is doing nearly nothing- there's too indirect of a heat-transfer path between it and the CPU. No wonder this thing wilts in the slightest heat. The EMI shield may be necessary (or may not be) but would be OK if a thermal epoxy like Arctic Silver is properly used to attach it to the CPU, then with the heat sink done the same way directly on top of that. It may require a longer cable and it's own shielding but the cable needs to be outside of the whole mess, not sandwiched in between where it is now impairing the heat path. You could even remove a fin or two off the heat sink to make a way for the cable to cross outside and you'd still get far better CPU cooling than this. And in the pics you can see the biggest failing of thermal putty- air pockets and incomplete coverage of the entire area involved. Now you have hot-spots in the CPU which is going to cause malfunctions and early failure. As it is now the EMI shield under the heat sink is doing most of the cooling- maybe almost all of it 😱

The principle of heat-sinking is to provide a larger radiant surface on the cold side while having maximum contact on the heat-generating side. The total amount of cooling available is basically a function of the total surface area on the cold side. This heat sink would work equally well with twice the fins at half the fin height, and given that the heat would then have twice the fins closer to it, the heat would travel to the fins to be dissipated even faster than it is now which would likely even improve the total cooling without any increase in the total surface area. This might even allow the cable to pass over the heat sink at it's current length. And even adding an EMI shield over the cable wouldn't significantly reduce the airflow which does the cooling; in fact if that shield were thermally bonded to the heat sink now you've got even more surface area to dissipate heat from. Even a push-fit cover here would transfer some extra heat and still give good EMI protection.

It's becoming clear to me that neither Zenfox nor whoever designed the heat sinking have a clue about what they're doing or they'd see the very basic mistakes they've made so it's no wonder they can't seem to fix the camera. This has been designed only to make cam assembly as cheap and quick as is possible while having something in there to show and use as an excuse that the cam factory did things the right way when they clearly didn't 👎 If Zenfox gives the slightest damm about his cam he will spend a dollar or two more per cam to get them built right with thermal epoxy and the redesigned cable routing which will then allow this cam to work in the same heat ranges that Thinklware, Garmin, and Blackvue are currently working in successfully.

Otherwise this cam is doomed, which is not how any of us wants the story to end.

Phil

I would step up your suggestion. If he really wanted the most optimal cooling, but didn't want to give up the heat shield placement, couldn't he setup things like so:

1. Copper plate on CPU with Artic Silver Thermal Paste
2. EMI Shield Affixed to Copper Plate with Artic Silver
3. Heatsink Attached direct to EMI shield with Artic Silver

Honestly, I agree this thing has a poor design and airflow. I've said that from the very beginning when I pointed out the device is overheating. No one believed me for a while, but now the facts are out, showing my assessment was correct.

I guess if Zenfox doesn't return here with an answer at some point, we all might resort to a few modifications on our own to see if we can get the camera stable. That doesn't help @Zenfox_Official, but would allow us to keep his camera in our vehicles, and use it as designed. It's to be seen if he will take our advice and fix his design flaws. I hope he does and sends out new cameras. Otherwise, this product is doomed.

As I mentioned earlier, I doubt any firmware will really fix this problem. Even if he ups the cutoff temperature, the heat from the cpu is being improperly dispersed. So the camera will probably just reach that new cutoff point, too.

 

[HonestReview]

There is no cable sandwiched under the heatsink, only tape!

From photos it looked like a ribbon cable. @EGS corrected us that it was tape.

Here's @kamkar1 photo:

Reducing the amount of pink stuff by replacing most of it with a sheet of copper, or less effective aluminium would help. Preferably larger than the processor to spread the heat quickly out over a wider area than it is at present.

The tape appears to be functional, so don't just remove it, it is needed to block the EMI escaping through the slots in the ends of the EMI shield/off the ribbon cable connectors. It does not need to go under the heatsink though, I have a T3 where it does not. If you modify it, make sure that it does all end up grounded (it is conductive tape), the EMI shield is also grounded.

Can you crack open your camera and take detailed pictures of your layout? If your camera is somehow different than everyone else's, we'd love to know what was done differently.

Where is the tape placement on your camera if not sandwiched between EMI and Heatsink? I presume your camera still has the EMI shield affixed to the CPU?

 

[EGS]

That pink stuff look like a thermal pad, you will see something similar on the memory and voltage parts on a computer GFX card.

This stuff in my camera is different material, more like play dough. Those in your picture look more like silicon pads. Don't know which one is better though..

 

[HonestReview]

This stuff in my camera is different material, more like play dough. Those in your picture look more like silicon pads. Don't know which one is better though..

His picture is of a computer graphics card, not his camera. For illustrative purposes of how thermal pads (pink goop) is used.

 

[EGS]

Can you crack open your camera and take detailed pictures of your layout? If your camera is somehow different than everyone else's, we'd love to know what was done differently.

Why not opening yours? That way you will have a direct understanding of how things where put together. At the moment your camera is as good as mine.
Maybe you and someone else is willing to do their own mods and see what the results are for each individual and compare with the rest.

 

[HonestReview]

Secondary Questions:

@EGS did you have to remove the supercapcitor when taking your photo? Does it easily come out with a pin to motherboard?

TO EVERYONE: Does the tape going over the supercapacitor and covering up the fins of the heatsink affect airflow, too? Could this tape be routed vertically over the supercapacitor instead horizontally and covering the heatsink?