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

[HonestReview]

I would like to stop and take a step back here so we're all on same page. We have 3 individual problems to overcome.

1. Adhering EMI shield to the PCB Board. @EGS had a solder joint on top left corner. Mine was only held on by pink goop. How will you hold EMI shield in Place?

2. I bought a Copper Plate .8mm Thick - Did you purchase these too? And if so what thickness?

--- How do you plan to adhere the Copper Plate if you purchased one? Will you adhere to the underside of EMI Shield with Solder or Epoxy? Or will you cut out a hole in the EMI Shied for the SOC to poke through. Then mount Copper Plate to the Heatsink?

3. How do you intend to mount the heatsink to the EMI shield and/or SOC?

What are each of you doing on #1, #2, and #3?

 

[Nigel]

I would like to stop and take a step back here so we're all on same page. We have 3 individual problems to overcome.

1. Adhering EMI shield to the PCB Board. @EGS had a solder joint on top left corner. Mine was only held on by pink goop. How will you hold EMI shield in Place?

I haven't modified mine, since I don't have an overheating issue, but in summary:

1. The board has clips into which the EMI shield fits, that should be enough to hold it in place as long as you don't stick a heavy heat sink on it.

EGS had a blob of solder which secured the EMI shield even better, but that was probably to ensure a good ground (0 volts) connection. A blob of solder on diagonally opposite corners would ensure it can not fall off, however I don't recommend this unless you are an expert at soldering.

Kamkar has added some foam, I guess between the heatsink and GPS module clamp?, which will assist in holding the EMI shield on and pressing the thermal paste joints firmly together. I think this is a good idea, probably a bit of silicone rubber might be better than foam.

2. I bought a Copper Plate .8mm Thick - Did you purchase these too? And if so what thickness?

--- How do you plan to adhere the Copper Plate if you purchased one? Will you adhere to the underside of EMI Shield with Solder or Epoxy? Or will you cut out a hole in the EMI Shied for the SOC to poke through. Then mount Copper Plate to the Heatsink?

2. EGS has a home made 0.8mm thick copper plate, Kamkar has nothing. I like EGS's plate, it is a good size for spreading the heat across the heatsink, which will add some cooling.

You should use a very thin layer of good quality thermal paste both sides of the plate, and under the heatsink.

Cutting a hole in the EMI shield is probably a bad idea, it is going to cause extra problems to solve, such as what is going to hold the heatsink in place.

To attach the copper plate to the EMI shield, solder is probably best, but unless you are an expert in soldering then I recommend copying EGS and using a blob of epoxy glue on each corner. Make sure you don't put the glue on thermal paste, because that will not work. An alternative would be to use a nail punch to put some indents in the top of the EMI shield around the copper plate so that once assembled it can't slide out of position, you can then just assemble in order, cpu - paste - copper - paste - EMI shield - paste - heatsink - rubber spacer.

3. How do you intend to mount the heatsink to the EMI shield and/or SOC?

A very thin layer of good quality thermal paste under the heatsink, then fix the heatsink in place with a few blobs of epoxy around the edge. Kamkar has used solder instead of epoxy, but he knows how to solder and has the right equipment.

Before you put the epoxy on, apply a clamp to squeeze together the copper, EMI shield and heatsink together, apply the epoxy and then leave it 24 hours to set. A weight could be used as a clamp but would be less convenient. If any paste squeezes out when you clamp it, leave it there in case it is needed to be drawn back in when the clamp is removed.

 

[HonestReview]

I haven't modified mine, since I don't have an overheating issue, but in summary:

1. The board has clips into which the EMI shield fits, that should be enough to hold it in place as long as you don't stick a heavy heat sink on it.

Well son of a bitch you are right. My unit was assembled improperly. Not only did the emi shield not have solder, the EMI shield was placed as if the clips were guides and not actually in the clips. So the pink goop was holding it in place.

FYI: Since the other unit is overheating, the improper mounting probably made things worse on this unit, but wasn't cause of the overheating.

Well that just made life easier....

I cancelled the thermal paste, and my whole how is this EMI shield going to stay attached, was based on the faulty assembly.

Thank you Nigel for pointing that out.

Quality control was lacking on my unit....

 

[HonestReview]

I have now reordered the MX-4 Thermal Paste.

 

[EGS]

It looks like my MX-4 will be delivered today! even though it was previously scheduled for Tuesday. I hope I do have some time to work on it later today after the order arrives.

 

[HonestReview]

It looks like my MX-4 will be delivered today! even though it was previously scheduled for Tuesday. I hope I do have some time to work on it later today after the order arrives.

I won't get the copper shim til Tuesday and the thermal paste should be Monday or Tuesday. I'll just need to buy epoxy to adhere the copper plate to the EMI shield and the heatsink to the EMI shield.

I still wonder though if I tried to do a cutout for the SOC, mount copper shim to heatsink, and have heatsink + Copper plate directly affixed to the SOC (instead of copper plate under SOC) if that'd be better.

Only worry is messing up the plate and then I'm SOL. Not sure how well a utility knife could cut out a hole without bending it.

 

[EGS]

I won't get the copper shim til Tuesday and the thermal paste should be Monday or Tuesday. I'll just need to buy epoxy to adhere the copper plate to the EMI shield and the heatsink to the EMI shield.

I still wonder though if I tried to do a cutout for the SOC, mount copper shim to heatsink, and have heatsink + Copper plate directly affixed to the SOC (instead of copper plate under SOC) if that'd be better.

Only worry is messing up the plate and then I'm SOL. Not sure how well a utility knife could cut out a hole without bending it.

I would suggest to wait until you get the copper shim and try it before you make any cuts. If it fits snug between the emi shield and soc, then I think you will be fine. If that doesn't work for you then you can try what you are suggesting if that is the path you want to follow.
Yes, remember you only have one emi shield on hand.

 

[Nigel]

There is also the issue that there will be a lot of heat under that EMI shield that needs removing, and if the heatsink is connected to the processor not the EMI shield then how does everything else under the EMI shield get cooled?
(Heat from the processor will go down into the PCB and heat everything under the EMI shield as well as up into the heatsink, then there is memory card etc. which is currently cooled by the heatsink, even if not very well!)

 

[EGS]

There is also the issue that there will be a lot of heat under that EMI shield that needs removing, and if the heatsink is connected to the processor not the EMI shield then how does everything else under the EMI shield get cooled?
(Heat from the processor will go down into the PCB and heat everything under the EMI shield as well as up into the heatsink, then there is memory card etc. which is currently cooled by the heatsink, even if not very well!)

True

 

[HonestReview]

There is also the issue that there will be a lot of heat under that EMI shield that needs removing, and if the heatsink is connected to the processor not the EMI shield then how does everything else under the EMI shield get cooled?
(Heat from the processor will go down into the PCB and heat everything under the EMI shield as well as up into the heatsink, then there is memory card etc. which is currently cooled by the heatsink, even if not very well!)

Sorry I typed and explained improperly You are right. Let me better explain my question:

If I did a cutout like the image below and mounted the Copper Plate UNDER the EMI SHIELD, would this work? EMI SHIELD ---Paste + Epoxy --> Copper -- Past-->SOC

So that the Heatsink sits ON TOP of the EMI SHIELD, but with a cutout, thereby sitting on top of the copper shim that is transferring heat from the SOC.

 

[EGS]

Sorry I typed and explained improperly You are right. Let me better explain my question:

If I did a cutout like the image below and mounted the Copper Plate UNDER the EMI SHIELD, would this work? EMI SHIELD ---Paste + Epoxy --> Copper -- Past-->SOC

So that the Heatsink sits ON TOP of the EMI SHIELD, but with a cutout, thereby sitting on top of the copper shim that is transferring heat from the SOC.

I would definitely remove the conductive tape as well as the nylon tape tat is underneath.

 

[HonestReview]

I would definitely remove the conductive tape as well as the nylon tape tat is underneath.

I peeled it back and will mount on metal. Just debating whether to make a cutout for the SOC so the heatsink can sit and touch the copper shim instead of conducting heat through the aluminum then copper.

 

[Nigel]

I peeled it back and will mount on metal. Just debating whether to make a cutout for the SOC so the heatsink can sit and touch the copper shim instead of conducting heat through the aluminum then copper.

I don't understand your "peeled it back", if you want the heatsink to touch the EMI shield properly then you have ro remove the tape, otherwise there will be a gap which will need an extra thick layer of paste, and that is bad.

Cutout, seems a bad idea to me, and apparently to everybody else too!

 

[SawMaster]

While the SOC will 'push' heat everywhere, the laws of thermodynamics say that most of it will go toward the coolest surface- ie the heat sink. And the other components are probably well within their operating temp range even now with everything too hot. Make the most direct solid path to the heat sink that you can. That's the key.

Judging from the various ways the EMI shield has been installed, it seems to me that the factory has taken liberties with the design to allow for faster cheaper easier production

Phil

 

[SawMaster]

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

 

[DrekiTech]

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!

 

[EGS]

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

yes, it is a known bug.

 

[DrekiTech]

yes, it is a known bug.

Ok thanks I searched the thread but couldn't find. ^^

 

[EGS]

Ok thanks I searched the thread but couldn't find. ^^

Check the gps info in this video that I uploaded a few weeks ago.

 

[HonestReview]

While the SOC will 'push' heat everywhere, the laws of thermodynamics say that most of it will go toward the coolest surface- ie the heat sink. And the other components are probably well within their operating temp range even now with everything too hot. Make the most direct solid path to the heat sink that you can. That's the key.

Judging from the various ways the EMI shield has been installed, it seems to me that the factory has taken liberties with the design to allow for faster cheaper easier production

Phil

Quality control is definitely lacking as demonstrated by our units overheating, the lack of solder on my emi plate, and it being improperly assembled. Again, I didn't know there were clips, because mine was never mounted into them!