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

[HonestReview]

It would most likely be OK for the cam to cut the EMI shield out at the SOC processor to allow for direct heat-sink attachment. The heat-sink itself will block direct radiation if you ground it to wherever the EMI shield grounds (preferrably with braid but wire is probably enough). But there is a chance that the EMI could find the new opening and escape between the shield and the heat-sink, and while that won't get back to the cam, that path could radiate away and cause interference with devices around the cam (car sensors, GPS, etc,). Personally I'd do that as I have junk I could close that hole back with if I had to. Or I could duplicate the EMI shield. You folks may not have the junk drawer and tools I do.

Anyone trying this needs to be sure the EMI shield does not contact any components under it, and be careful about that when you top the stack off with the heat sink. Also ground the heat sink so it can act as a EMI shield.

Phil

I have a question and this appears to affect @EGS , too. Definitely need some guidance here:

https://dashcamtalk.com/forum/threa...invitation-limited-quantity.42404/post-517840

I am sure my 20x20x8mm shims will contact diodes, capacitors, and other components on the pcb in addition to the SOC. As does the shield @EGS created, if you look at my link. His shield sits on top of the SOC but most likely contacts other components on the pcb board, too.

Will I need to cut my shim down to the size of the SOC? I am not sure I properly understand your comment, but if I am reading things right, we don't want the copper plates to touch anything EXCEPT the SOC? Meaning I need to trim it down to exact 20x15mm (or there abouts) so it sits on top and ONLY ON TOP of the SOC for fear of shorting out other components?

So is it not safe to use epoxy to glue the copper shim to the EMI Shield unless i cut the copper plate to exact size of the SOC?

Bit confused now.

Or am I incorrect in reading what you wrote

 

[HonestReview]

It would most likely be OK for the cam to cut the EMI shield out at the SOC processor to allow for direct heat-sink attachment. The heat-sink itself will block direct radiation if you ground it to wherever the EMI shield grounds (preferrably with braid but wire is probably enough). But there is a chance that the EMI could find the new opening and escape between the shield and the heat-sink, and while that won't get back to the cam, that path could radiate away and cause interference with devices around the cam (car sensors, GPS, etc,). Personally I'd do that as I have junk I could close that hole back with if I had to. Or I could duplicate the EMI shield. You folks may not have the junk drawer and tools I do.

Anyone trying this needs to be sure the EMI shield does not contact any components under it, and be careful about that when you top the stack off with the heat sink. Also ground the heat sink so it can act as a EMI shield.

Phil

In addition...If I say made a cutout in the EMI shield, the copper plate expoxied to the EMI shield wouldn't block out interference? Even if I then had the heatsink mounted on the EMI shield and then mounted on the cutout for Copper -- SOC?

 

[HonestReview]

I just got mine to test.

Anyone else have GPS Stamp issues? on front cam it's correct, but on interior and rear cam, it is way over!


View attachment 52591View attachment 52592

Just wait until the sun starts shining. We're all trying to devise various methods to deal with the camera shutting itself down on the first signs of a hot day. Rear, Interior, and eventually the front camera stop recording. GPS is least of the worries.

 

[Nigel]

I am sure my 20x20x8mm shims will contact diodes, capacitors, and other components on the pcb in addition to the SOC. As does the shield @EGS created, if you look at my link. His shield sits on top of the SOC but most likely contacts other components on the pcb board, too.

That would be a disaster.

Will I need to cut my shim down to the size of the SOC?

Clearly EGS is not going to do so, I'm pretty sure that he has already checked that there will be no contact with any other component than the SOC, however you need to take responsibility for your modification.

So is it not safe to use epoxy to glue the copper shim to the EMI Shield unless i cut the copper plate to exact size of the SOC?

The bigger the plate, the more it will spread the heat, and the cooler the SOC will become. You do not want to reduce the plate size unless it is necessary.

In addition...If I say made a cutout in the EMI shield, the copper plate expoxied to the EMI shield wouldn't block out interference? Even if I then had the heatsink mounted on the EMI shield and then mounted on the cutout for Copper -- SOC?

Most of the interference would be blocked, but think how difficult it is to find somewhere where your phone can't receive a phone signal, even inside the metal box of your car. When I put my Viofo MT1 in my engine compartment, it was completely surrounded by metal, yet the wifi signal inside the cabin worked perfectly. Microwaves are very good at escaping, and modern high speed processors radiate a lot of microwaves.

You are going to lose most of the structural strength of the EMI shield if you cut a big hole in it that gets very close to one side, how are you going to regain that strength so that it is capable of holding the heatsink? I don't think epoxy is a good answer, I would want to solder the copper to the shield, filling in all of the gap, then the EMI can't escape and the structure is solid. However I would prefer a larger copper plate, like EGS's, since that will give better heat transfer, but if he cuts a hole in the shield big enough for his plate, there will be hardly any shield left! If you really want to take it to extremes then you should use a heatsink that reaches down onto the CPU, so that there is only one contact surface needing thermal paste, however even then you would want the lower bit to be copper and the upper bit aluminium.

Just wait until the sun starts shining. We're all trying to device various methods to deal with the camera shutting itself down on the first signs of a hot day. Rear, Interior, and eventually the front camera stop recording. GPS is least of the worries.

That is just not true, even for you, living in the heat of Death Valley, it does not shut down, it only cuts back on the number of channels recorded.

 

[kamkar]

I have not been able to make mine drop channels when recording, but as said earlier i have seen a few times that when shutting down a channel can be missing.
But in general when recording mine also record all 3 channels.

I dint think what i have of problems are not as muh heat related but rather memory card incompatibilities, and the one A1 card i got for this, was of course the wrong one to get ( kingston )
But next week i get a new card ( not kingston ) and it is even A2 rated.

ADATA

ADATA Product

www.adata.com

If that dont work in the T3 it will work in my 4K/60 action camera recording in 100 mbit

AND ! It got warranty for use in dashcams, and a lifetime warranty too. ( at this time in dashcam history i feel i can only recommend people to buy memory cards with warranty for dashcam use )

 

[SawMaster]

Microwaves are very good at escaping, and modern high speed processors radiate a lot of microwaves.

That is the problem, but it wouldn't likely affect the cam itself. And looking at the pics, there are openings for EMI to escape already.

Any metal- even thin foil- can create an EMI shield. One unseen problem with shielding at these frequencies is that whatever hits the shield will bounce off of it and whatever metal it encounters thereafter until it finds a 'hole' to escape, sort of like a banked billiards shot that never ends. And also any slick hard surface (including window glass) can reflect microwave 'signals' too.

As long as nothing else gets in the way any size 'plate' which completely covers the entire SOC chip will do- that entire covering is what matters most. And yes, any larger pieces will add to the heat sinking but given the restraints of the cam case that wouldn't amount to much.

Phil

 

[SawMaster]

I don't think what i have of problems are heat related but rather memory card incompatibilities

You and Nigel are in cool enough climates so that you may not experience overheating issues, at least not as much as others. But there are more problems with this cam than heat alone including card compatibility. Which we know can and often does happen with cams which do this much writing to the card. All parts of any system must work together correctly to obtain the desired results.

Best cards can be discovered, and firmwares are not too hard to change, but without the hardware working correctly that won't matter. Got to get the hardware right first

Phil

 

[EGS]

I am sure my 20x20x8mm shims will contact diodes

Based on what? Your own research? That sounds so affirmative...

 

[kamkar]

Since the SOC are offset quite a bit towards one side / corned of the EMI shield, it dont make much sense to put a larger shim over it to cover the gap the thermal pad ( gap-filler ) was covering.

But otherwise as i saw it the SOC are #2 tallest and only the SD card "slot" are taller, and in my camera the wifi chip ( i assume it is that ) was the same height as the SOC )

So if you use a larger than SOC cobber shim, well it would funnel heat out over a larger area of the ALU heat sinks footprint, but as you get off the SOC, wont the heat then have to travel "sideways" and so thru a "thicker" part of cobber as it is not moving up thru the shim but first to the side and only then up into the ALU heat sink.

Using a larger than SOC shim i think will only bring marginal thermal conductivity improvements.

 

[EGS]

I have a question and this appears to affect @EGS , too. Definitely need some guidance here:

https://dashcamtalk.com/forum/threa...invitation-limited-quantity.42404/post-517840

I am sure my 20x20x8mm shims will contact diodes, capacitors, and other components on the pcb in addition to the SOC. As does the shield @EGS created, if you look at my link. His shield sits on top of the SOC but most likely contacts other components on the pcb board, too.

Will I need to cut my shim down to the size of the SOC? I am not sure I properly understand your comment, but if I am reading things right, we don't want the copper plates to touch anything EXCEPT the SOC? Meaning I need to trim it down to exact 20x15mm (or there abouts) so it sits on top and ONLY ON TOP of the SOC for fear of shorting out other components?

So is it not safe to use epoxy to glue the copper shim to the EMI Shield unless i cut the copper plate to exact size of the SOC?

Bit confused now.

Or am I incorrect in reading what you wrote

You have an open unit in your hands. One in which you can verify simple things like that. You could cut a piece of thin flat cardboard from a cereal box or similar and place it on top of the SOC, then you can check is any components are at the same height as the SOC or higher.

I did similar work to check and see how much clearance I had from the SOC surface down as well as to determine my gap between SOC surface and emi shield.

By the way. I assembled mine last night after receiving the thermal grease and will put it to test today and see how it will perform. I'm not setting my hopes high though. Will report later

 

[kamkar]

The SOC also just touch a corner of the ALU heat sink, heat absorption of the heat sink would probably be better if the SOC was right in the middle of it.
Using a shim to move heat sideways to be able to reach a larger part of the heat sink footprint i dont think will give much performance.

 

[kamkar]

I uses a banking card to put on the top of the SOC to see what was higher, though a ATM card probably dont have a 100 % strait line, it was the best smaller thing i had to gauge that.
I only had my caliber on the SOC to measure its height off the PCB, did not measure the other parts of interest.

 

[kamkar]

The connectors for the cameras, or at least the near one, if i put my ATM card on it and the SOC you could see there was a gap indicating the camera connector was taller, but it is probably less than 1 mm we talk about.
But thats also plenty if you want something larger like the EMI shield to sit flush with the SOC top surface.

 

[kamkar]

So in my case being the low rider fan, i slammed everything down, so i had to cut gaps in the EMI shield for the taller things like memory card slot and the 2 camera connectors.

 

[kamkar]

how looooow can you go,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, LIMBO !

 

[EGS]

I uses a banking card to put on the top of the SOC to see what was higher, though a ATM card probably dont have a 100 % strait line, it was the best smaller thing i had to gauge that.
I only had my caliber on the SOC to measure its height off the PCB, did not measure the other parts of interest.

I used similar techniques as you did as well as using a caliper

 

[Nigel]

Remember that the supercaps still have power in, so don't use something made of metal for that test, unless you discharge the supercaps first.

 

[SawMaster]

So in my case being the low rider fan, i slammed everything down, so i had to cut gaps in the EMI shield for the taller things like memory card slot and the 2 camera connectors.

I don't think this will be much of an issue if any, but the possibility exists. Ideally the heat-sink would have a raised pad milled on the bottom to contact the chip directly, with the EMI shield having a tightly fitted hole for that pad to pass through. In the real world that would not be feasible for a production product unless no other way worked at all.

As far as an intermediate shim or spacer not being centered that will have little effect, as most of the heat will seek and find the coolest area to go to through whatever path it has available. There would be some temperature differential but not enough to be concerned with. Heat sinking is pretty simple overall, but EMI can get complicated in a hurry

Phil

 

[Nigel]

Using a shim to move heat sideways to be able to reach a larger part of the heat sink footprint i dont think will give much performance.

 

[HonestReview]

That would be a disaster.

Clearly EGS is not going to do so, I'm pretty sure that he has already checked that there will be no contact with any other component than the SOC, however you need to take responsibility for your modification.

Based upon my own test and attached photos.....See Circled Diode - It's the same height as the SOC. Meaning if what you all say is true about contacting other components, the Copper Shim needs cut down ONLY to fit on top of the SOC. The Media Card Adapter is 20/21CM wide. Same size as the copper plate I ordered (20x20x8mm) - 20 long, 20 wide, 8mm thick.

The bigger the plate, the more it will spread the heat, and the cooler the SOC will become. You do not want to reduce the plate size unless it is necessary.

Correct, except bigger here means issues.

Most of the interference would be blocked, but think how difficult it is to find somewhere where your phone can't receive a phone signal, even inside the metal box of your car. When I put my Viofo MT1 in my engine compartment, it was completely surrounded by metal, yet the wifi signal inside the cabin worked perfectly. Microwaves are very good at escaping, and modern high speed processors radiate a lot of microwaves.

Which is why I asked of course.

You are going to lose most of the structural strength of the EMI shield if you cut a big hole in it that gets very close to one side, how are you going to regain that strength so that it is capable of holding the heatsink? I don't think epoxy is a good answer, I would want to solder the copper to the shield, filling in all of the gap, then the EMI can't escape and the structure is solid. However I would prefer a larger copper plate, like EGS's, since that will give better heat transfer, but if he cuts a hole in the shield big enough for his plate, there will be hardly any shield left! If you really want to take it to extremes then you should use a heatsink that reaches down onto the CPU, so that there is only one contact surface needing thermal paste, however even then you would want the lower bit to be copper and the upper bit aluminium.

If you soldered the Copper Shim to the EMI shield, the question belies would the EMI shield retain it's integrity? I ordered these: https://www.amazon.com/gp/B00OUJQUR4

That is just not true, even for you, living in the heat of Death Valley, it does not shut down, it only cuts back on the number of channels recorded.

Just because the UK never sees sunlight and warm weather, doesn't mean there's not a problem. Everyone has confirmed this issue, except @kamkar1 and you. Meaning a problem exists, whether you choose to admit it or bury your head in the sand and pretend all is well!