Aftermarket Android head unit not switching on sometimes

[CALEB]

Must say your ingenuity on install is impressive, haw do you get the MOT tester to pass it as surly its obstructing view of sweep of wipers. have you considered connecting it up on bench and spraing various parts with this kind of stuff https://media.rs-online.com/t_medium/F1681648-01.jpg should pinpoint an area to concentrate on. and you not out in cold while doing it.

Ok, thanks I will investigate this option. (It may take time to order the stuff)
Connecting it up on bench can be problematic though, because this unit also needs a canbus box connected to the wire harness and communicating with the car. It cannot power on outside the car. (or some car emulating setup, like they use in the manufacturing testing)

About obstructing the view - not really, it's just the angle the picture was taken. If I sit on the driver's seat, the screen only obstructs a very small part of the area that has only the view of the bonnet. It is not distracting even at nights. (Or, of course, it depends on how tall I sit - I could sit very low and then it would obstruct my view, but not if I sit normally.)
There is also a wide gap between the screen and the window, so I can tilt my head to see the area the screen was obstructing. (not needed really)
That being said - I haven't had the MOT test with this modification yet. (Installed the stuff almost a year ago, after the last MOT test and there is another year until the next test)
So, I cannot really say 100% that it will pass. Ultimately it depends on the person who runs the test and how I can justify it. (I can always remove the screen during the test - it takes less than 5 minutes)


- Or maybe I'll install some kind of hinge that enables to fold the sceen down if neccessary. (Theoretically it is even possible to make it slide-out upwards from the dashboard)

[Ian_Insignia]

That's a good idea about the freezer spray - you can probably buy it locally.

The cracks in components I refer to is with ceramic chip capacitors, small grey or brown surface mount, with metalised terminal each end.
We have to be very careful how we solder these because the do not like thermal shock of the hot soldering iron touching the terminal. It cracks the ceramic, and over time, they go open circuit.
We actually heat the circuit board and components to 100C before we solder them to the PCB to avoid this thermal shock.
You would never see the internal damage visually unless you cut open the component (which we do here as part of failure analysis).
Also, if the parts is weak (due to low cost, low quality, or stressed when touched with soldering iron) then the damage will occur during thermal cycle (which we do to induce failures).
Your radio get thermal cycle hot/cold, so over time this will eventually break the component.
You will never be able to see this kind of failure mechanism.
If you attempt to re-flow the solder on ceramic chip capacitors, it will likely induce damage.

If your get the radio hot, and it works, then you locate the problem with freezer spray, and it is a ceramic chip capacitor, just be very careful how you solder the new one.
Use a soldering iron with say 250C tip, and SnPb solder is always best. Move the iron towards the solder pad on the PCB, never touch the chip capacitor or terminal with the iron.
Use plenty of flux to get a nice joint quickly.
Good luck!!!!
Ian

[CALEB]

Thank you for the information. I'd like to point out one thing though - you said to use a soldering iron with 250C tip, but these cheaply made chinese circuit boards have some kind of non-pure solderings, that are almost impossible to melt with anything under 380C. I have my soldering station set to 386C to be able to solder these boards and even then some bigger blobs of this crap-mixed tin can not be melted. It just turns into some kind of granular mash.

Any idea about using this freezer spray on the circuit board when the board is not powered on ? (This unit cannot be powered on outside the car because of the canbus, and not possible to power on inside the car while being dismantled - I'd have to create some kind of long wiring harnesses to do that and there is a risk to the car's systems if tinkering with the unit while it's connected to the car.)

I know - everything about this problem seems to be complicated (because it is). That's why I havn't been able to correct it so far. For all I know, the failure may be inside the canbus box instead of the main unit. (Not very likely though). I'll check this by removing the canbus box only and warming it up and then try. (It may take some time though, because I park my car outside where it's dark and cold and rainy by the time I finish work and finally have time to deal with this. And then everything should be put back together before next morning. Need some free days with tolerable weather.)

[Ian_Insignia]

I have no idea what that solder is on your PCB! We just do very traditional soldering here with 63/37 tin lead solder.
It sounds like your PCB was never intended to be repaired or re-soldered!

The purpose of the freezer spray is to detect which component fails when it gets cold. And of course you need the radio to be operating when you do this, so you can detect some failure. It is a very crude method, but obviously must work in some circumstances. I think you probably have lots of components on the PCB, so even if you could find a local area that fails when it gets cold, there would still be lots of components and solder joints to consider as possible defects.

if the radio operates when warm, the consider what the other guy said and keep it slightly warm with a heater, eg low value resistors. It probably only doesnt need to be very warm to work.

You have done a lot of work, so I can understand your desire to fix the problem! You have difficult situation to work in though!

[CALEB]

I need a drink...

[Ian_Insignia]

Well I have decided NOT to get the cheap chinese android replacement radio/cd/nav.
I think I will have to get the expensie adaptor plate, and a standard double DIN radio/cd/nav.
The one I like is PUMPKIN. It has built in nav, so it works if I forget my phone.

So I want to achieve this:


Caleb, since you have very intimate relationship with the space behind your centre facia, can you tell me if the depth is sufficient for 160mm deep Double DIN unit.

[CALEB]

Should be - there is some kind of plastic support behind the original unit, I sawed it off to get more room for the wires. Without this support there's quite a lot of room.
But even with the plastic support it should fit.

[Ian_Insignia]

Thank you.
The standard depth of these double DIN units seems to be ~153 (Kenwood) to ~165mm (Pioneer).
Probably limited by the size fo the CD player.

[CALEB]

A small update - I think I fixed my unit. I replaced all capacitors - also SMD types. As a replacement, I used regular capacitors (not SMDs) because what I read about these SMDs is that they only last about 1000 hours. It's been a while since I replaced them and the device works normally. Starting up every time. (Even at lower temperatures)