Solo2 HDMI problem after power cut

caillou

Vu+ Newbie
Hi ALL,

I have a weird problem 3 PVRs have the same issue after a power cut, before this happened all 3 been working fine for years. After home mains power was restored HDMI no longer works and will produce the same error on Screen - N0 Signal. All TV has been tested with other devices and HDMI work fine.

All 3 are genuine and out of warranty, models are SOLO 2 X 2 and 1 ZERO.
The Solo2 works fine on Scart.

A fresh image did not fix the problem.

I have checked the inside these have never been repaired however they came to me to be fixed.
The HDMI port under the microscope looks brand new.

From openwebif I can see that all 3 are working fine.
Before I attempt anything I would like your suggestion on why this may have happened and what steps I should take, settings re HDMI in PVR are FINE.

I am an electronics engineer with 20 + years of experience and have never seen anything like this before, does anyone have a schematic for these models or a link where I can match resistance value and diodes in circuits, please? I have tested for short to ground however found nothing so far.

Any help & ideas are welcome thanks.
 

AlexWilMac

Moderator
Is not a weird problem: every devices like computers or TVs or receivers should be connected to a UPS or, at least, to a surge protection: electronics is very sensitive.
It doesn't make sense to connect them directly to the power.
As an engineer you should be perfectly aware of that and they should have taught to you that.
 

caillou

Vu+ Newbie
Thanks for the reply,

I have no control over what those who bought these 3 receivers do with them, I just repeated what I was told. My task here is to repair them or call it a day.

I am a qualified electronics technician and I do this for living so not sure if I understood your post correctly unless you are telling me I am not authorized to do such repair.

From what I can notice all models have surge and ESD protection chip but still that would not answer my questions.

1> Why only the HDMI issue?
2> Why do all TV HDMI ports still work fine with other devices?
3> Why do these die all at the same time.

Let's be real now who uses UPS on TV and Reciever?

Re mains 240v, he has a surge protector for all the house, repower cut they press the RCD for 20 mins for doing house maintenance and when they switch the power back they found this issue, sounds incredible to believe it but that what was told, such issue should never happen with power off and power on from standby.

All 3 have a common chip which is IP4786CZ32. The task of this chip is to protect the CPU from ESD and Surge, any way anyone can help me test around it, please?

Thanks in advance
 

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You write... The Solo2 works fine on Scart.
So I assume the TV sets are maybe not FullHD but HD Ready??
Have you checked if the boxes has started in 1080p ?
Have you try the 720p settings to see if they give signal

Would be like winning the lottery if 3 devices would break at the same time with the same fault
 

Matrix10

Administrator
The only possible cause if all receivers are damaged at the same time is of course static or other voltages (inductive voltages, etc.) which destroyed the HDMI ports. If you have ruled out other possibilities, this is the direction you need to go look for the cause and possibly repair.

The IP4786CZ32 is designed to protect High-Definition Multimedia Interface (HDMI) transmitter host interfaces. It includes HDMI 5 V overcurrent / overvoltage protection, Display Data Channel (DDC) buffering and decoupling, hot plug detect, backdrive protection, Consumer Electronic Control (CEC) buffering and decoupling, and ±12 kV contact ElectroStatic Discharge (ESD) protection for all I/Os, exceeding the IEC 61000-4-2 level 4 standard.

If it is HDMI, and does not work with the direct signal, but also with the recorded one or test video with recorded video from USB / HDD then try to replace that chip.
 
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caillou

Vu+ Newbie
Thanks once again for your reply,

Finally, that is what I am trying to say it is weird that 3 devices on the different floors with different brands of TV would have the same fault at the same moment.

It was tested on different TV which is known as good HDMI ports with Fresh Black hole image. No settings have been touched Solo 2 = 1080P on Full HD TV and Zero was set 1080i on HD READY, they have worked fine for over 7 years.
It is not easy to remove this chip since it is surrounded by Plastic (HDMI PORT) so I need to make sure that this chip is faulty, value of the chip costs only €0.75.

A UPS will not protect you, both ZERO and SOLO2 using external High voltage SWITCH PSU so a UPS is useless when it comes to helping in any voltage issue.

In my Lab, the only protection I have is on my oscilloscope since I do not want to blow myself with it for the rest it is BS, computers do not need a UPS just make sure to have a backup, and electronics are not that sensitive even though ESD is real. UPS is required if you have LIVE DATA such as SQL or RAID since they are very easy to get corrupted if power is lost and end result will be data loss.

The above is my opinion if you think a UPS is a must it will be OK if you can afford one and keep it maintained with fresh batteries.

These are models from the 2013 mainboard since before this HDMI was direct tracks to the CPU as shown in my attached image, lots of people fry the CPU by just removing the HDMI while the device was ON, VU due to complaints and RMA added this chip I mentioned above as a FIX for ESD. All I need is a schematic for HDMI or values in this area if anyone can help me I would appreciate it.

Thanks
 

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AlexWilMac

Moderator
I haven't talked only about UPS but also about surge protection outlets...
But, if you think they are useless, whatever. I don't think so. But it's you the engineer.
 

Matrix10

Administrator
I doubt very much that anyone here has a schematic
But I believe you can draw it yourself if you have the information
about chips.
I believe it is just one between CPU and HDMI input.

I think
With hot air this could be tried to fix (replace the protection chip)
of course you have to protect the plastic
use plenty of flux and easy blowing.

if we look at the input and output of the chip
we see + and - d0.d1.d2
Perhaps you can even use the comparison method to determine with a resistance meter whether the ports are OK (receiver off) and input/uit esd diodes.
With the voltmeter you can check the 3.3 and 5 V voltage in working condition
and with an oscilloscope you can still check the clock signal and more.
if we look at the input and output of the chip
we see d0.d1.d2

https://nl.mouser.com/datasheet/2/916/IP4786CZ32-1320007.pdf
 
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caillou

Vu+ Newbie
Thanks, matrix, without a schematic we can only guess unless I get values in the circuit.
Since these are sold cheaply I can buy a used SOLO2 working replacement. Like that, I can have working compare values.

Re hot air alone it is an impossible task since these QFN packages need 350 - 380c direct heat for 7 -15 secs and space is only 5mm therefore to be removed without damage the options are 2:

1> Use an under PCB focal heater to establish the heat around 200c then apply low solder melt (170c) by covering the chip + flux and use hot air with the smallest nozzle as shown in my image, however, this will require attention not to make mass to the nearby components since it is liquid and will spread easy after heated that's how it will go under the chip and make the solder flow at low temp.

2> Safest option remove HDMI Port and protect the other plastic around it.

Both approaches will be expensive so unless I take this as a challenge I need to quote and decide from there but since they have 3 faulty there is room to work and make little profit if they get fixed.

I will keep you updated and hope I help anyone that might have the same problem.

Thanks
https://www.instructables.com/PCB-Heater-Diy-Joule-heating/
 

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Matrix10

Administrator
Of course, it is not easy.
I have to say that in my career I have changed far heavier chips
with a soldered layer of cooler under the chip or microprocessors with far smaller pin spacing.
The truth is, I don't do that anymore except out of curiosity if I still can.:D
My eyes are no longer the same as when I was younger,and now I have a different job.
Liquid flux is ideal for this if you do not have a rework station.
He lowered the required temperature.
First heat the PCB from the bottom if possible
maybe with a hot gun if you don't have anything better.
Make the PCB very stable and with the lowest possible speed of hot air due to the surrounding components, peel off the chip ,
take off with with tweezers
HDMI connector protect with metal plate or aluminum plate / foil.
You can also solder a new chip with a soldering iron if you are afraid of the temperature.
I believe a measurement would show if the chip is broken
because there is a good chance that some protection diode has broken.
And since all HDMI pins inputs and outputs are i think the same, perhaps a comparison will give a result and a conclusion.

I even think HDMI would work without a chip.
It only serves to protect the microprocessor.
 
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caillou

Vu+ Newbie
I agree with you, our eyes are normal not to be the same after years that's why such a task has to be done only with a microscope unless your eyes can work with 0402 components.

Re possibilities depend on your OCD level, I would not accept a working HDMI port that has plastic bubbles due to too much heat even if the port works fine. We repair warranty electronics for shops in my area, our work has to be like factory perfect, in most cases we do a better job then robots.

I use HOT Block Putty heatsink but in such a small space, it will still not work, low melt solder is best the only extra task will be cleaning afterwards since this will create dry joints if left on PCB, this is a time saver if you have never used it. As shown in this video covering all areas around with Kapton tape will help not to spread solder liquid to other components but sometimes this does not work due to flux getting under the tape so extra care is a must not create extra work.


I have seen many YouTubers replacing HDMI ports and I do not know how they can upload a video and call it a pass but it all depends on your quality of work. Under heater helps a lot to spread heat evenly on the PCB without damaging plastics or discolour the PCB (220c max is safe for ABS).

Soldering QFN32 by hand is asking for trouble, this has to be done by reflow so it is not possible to do it by hand and pretend to work for years to come :offtopic:

Good example:

:thanks:
 

Matrix10

Administrator
You know sometimes you have to work with what you have.
We didn’t even have a hot gun at first so we worked.
Professional rework stations cost a lot.
All I know is that I would replace that chip in 15 minutes with magnifier and hot gun
hhahahh :wallbash:

Now you younger ones have more options.
My job was not with SAT receivers but with telecommunication devices including and
air communication and later mobile stations for GSM.
And the beginning was with electronic tubes.
Now it's more IOT devices and software, so my back hurts from sitting :help:
Good luck...
 

caillou

Vu+ Newbie
Once again you are correct.

I forget to add how I would install QFN32 if there will be the need and reflow at normal temp with no damage, this is easy with the tools.
I have a kit that attaches to my heat gun with the help of a preheater in this case it is a must. This will allow perfect reflow / no thermal shock and focus heat on a small area.

For anyone interested, this tool is called a QFN protector and yes it is expensive. The model I have should be used only for installation there is 5 digit model which is out of my budget and can also extract QFN and BGA with the help of a vacuum.

I will keep you updated as soon I find a USED solo2 with the same MB at a cheap price I hope.
Thanks for now.
 

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