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Beo6 with no touch functionality.

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Weebyx
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Weebyx Posted: Tue, May 19 2020 11:15 AM

Hi All.

Having gotten a Beo6 included in a deal, with the seller telling me it needed a new battery, I figured, not a problem. 

I have been able to get the most annoying Beo5/6 back to life, so gave it a new battery, and uploaded new BeoLo/FW/WiFi and configuration.

All worked, and it came back to life. The wheel and backlight works, and display shows all the right stuff. But touch is dead…

Has anyone ever had luck in getting touch back to life ? I suspect this actually IS a hardware issue, as I have tried all kinds of resets and config uploads.

Any idea ?

/Weebyx

matador43
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matador43 replied on Tue, May 19 2020 1:29 PM

Hi Weebyx,

Got one, back to life thanks to your help, with unresponsive touchpad.

Opened the screen to see what i could try. Appart from checking the ribbon cable, it looks to me there's nothing on that PCB that would be easily serviceable.

I ended up programming the hard keys to my use on a BC6 (TV/STAND/Apple TV/Radio/Airplay) and having the screen displaying the current function, as a Beo4 do. It's the best I could do and I use it now all the time. 

All this to say, I would be interested if there was any fix to it!

Weebyx
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Weebyx replied on Tue, May 19 2020 2:39 PM

matador43:

Hi Weebyx,

Got one, back to life thanks to your help, with unresponsive touchpad.

Opened the screen to see what i could try. Appart from checking the ribbon cable, it looks to me there's nothing on that PCB that would be easily serviceable.

I ended up programming the hard keys to my use on a BC6 (TV/STAND/Apple TV/Radio/Airplay) and having the screen displaying the current function, as a Beo4 do. It's the best I could do and I use it now all the time. 

All this to say, I would be interested if there was any fix to it!

Yes, this seem to be a HW issue, and not much to do about it :)

Oh well. It is good for parts :)

manfy
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manfy replied on Tue, May 19 2020 2:51 PM

First I'd probably go the service menu and see what the touch screen test comes up with. (according to Beo5 manual you can enter the service menu from the setup menu by pressing the sequence  0 0 GO )

If the touch screen is spoilt, there's probably no real easy or cheap way to fix it. Get a new screen from Beo.
I have no actual experience on this device, but after having fiddled around with some mobile phone touch screens long time ago, I'd think that the chances of success for a permanent repair of the screen itself are very slim.

Weebyx
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Weebyx replied on Tue, May 19 2020 6:22 PM

manfy:

First I'd probably go the service menu and see what the touch screen test comes up with. (according to Beo5 manual you can enter the service menu from the setup menu by pressing the sequence  0 0 GO )

If the touch screen is spoilt, there's probably no real easy or cheap way to fix it. Get a new screen from Beo.
I have no actual experience on this device, but after having fiddled around with some mobile phone touch screens long time ago, I'd think that the chances of success for a permanent repair of the screen itself are very slim.

It is not possible to go into the service menu, since the 0 0 Go, requires the Touch Screen to work ;)

/Weebyx

 

manfy
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manfy replied on Tue, May 19 2020 7:30 PM

Weebyx:
It is not possible to go into the service menu, since the 0 0 Go, requires the Touch Screen to work ;)

/Weebyx

hmmm ...so it's one of those 21st century "smart" products then, is it?  Unsure well, in that case you're probably just sheer out of luck...

 

manfy
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manfy replied on Wed, May 20 2020 12:12 PM

I've done some more digging and it seems that you may not be completely out of luck after all.

The official B&O marketing video shows some details that are very interesting.

This is the main board, ie. the motherboard of the unit and it is part of the display module. The bad thing about that is that the official replacement display module from B&O is probably prohibitively expensive. The good thing is that it shows the flex cable connector, which is a potential source of a malfunctioning digitizer (that is the thing that provides touchscreen functionality).
Beo6 uses a capacitive touchscreen and that is probably an integral part of the screen (as opposed to the resistive sytem used in Beo5). Since touch functionality is completely absent there are only 2 primary error sources: a contact problem between screen and motherboard or a damaged touch controller (the latter is possible but unlikely). Similarly, a complete malfunction of the transparent touch layers on the screen is rather unlikely.

So, if you're lucky, a simple unplugging and replugging of the flex cable might fix the whole problem. You only have to figure out how to disassemble the display module. I'd guess it works in a similar way as modern mobile phones. There could be some tiny screws somewhere at the base of the display and once removed you just need a pry tool to separate the cover from the screen.

In the Beo5 service manual I noticed that B&O used a standard TFT screen from Samsung. That's a standard product you might get off the internet. So if there's something wrong with the TFT screen + touchscreen layer, you might actually get a new one for, I don't know, say 50 bucks? That might be worth it. Just make sure you find a model number on the screen unit when the display module is disassembled.

Weebyx
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Weebyx replied on Fri, May 29 2020 7:39 AM

manfy:

I've done some more digging and it seems that you may not be completely out of luck after all.

The official B&O marketing video shows some details that are very interesting.

This is the main board, ie. the motherboard of the unit and it is part of the display module. The bad thing about that is that the official replacement display module from B&O is probably prohibitively expensive. The good thing is that it shows the flex cable connector, which is a potential source of a malfunctioning digitizer (that is the thing that provides touchscreen functionality).
Beo6 uses a capacitive touchscreen and that is probably an integral part of the screen (as opposed to the resistive sytem used in Beo5). Since touch functionality is completely absent there are only 2 primary error sources: a contact problem between screen and motherboard or a damaged touch controller (the latter is possible but unlikely). Similarly, a complete malfunction of the transparent touch layers on the screen is rather unlikely.

So, if you're lucky, a simple unplugging and replugging of the flex cable might fix the whole problem. You only have to figure out how to disassemble the display module. I'd guess it works in a similar way as modern mobile phones. There could be some tiny screws somewhere at the base of the display and once removed you just need a pry tool to separate the cover from the screen.

In the Beo5 service manual I noticed that B&O used a standard TFT screen from Samsung. That's a standard product you might get off the internet. So if there's something wrong with the TFT screen + touchscreen layer, you might actually get a new one for, I don't know, say 50 bucks? That might be worth it. Just make sure you find a model number on the screen unit when the display module is disassembled.

The circled connector is for the display, the touch connector is smaller, but I have disconnected/cleaned and re-connected both, and still nothing. It seems the Touch is just dead..

/Weebyx

Keith Saunders
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Weebyx:

manfy:

I've done some more digging and it seems that you may not be completely out of luck after all.

The official B&O marketing video shows some details that are very interesting.

This is the main board, ie. the motherboard of the unit and it is part of the display module. The bad thing about that is that the official replacement display module from B&O is probably prohibitively expensive. The good thing is that it shows the flex cable connector, which is a potential source of a malfunctioning digitizer (that is the thing that provides touchscreen functionality).
Beo6 uses a capacitive touchscreen and that is probably an integral part of the screen (as opposed to the resistive sytem used in Beo5). Since touch functionality is completely absent there are only 2 primary error sources: a contact problem between screen and motherboard or a damaged touch controller (the latter is possible but unlikely). Similarly, a complete malfunction of the transparent touch layers on the screen is rather unlikely.

So, if you're lucky, a simple unplugging and replugging of the flex cable might fix the whole problem. You only have to figure out how to disassemble the display module. I'd guess it works in a similar way as modern mobile phones. There could be some tiny screws somewhere at the base of the display and once removed you just need a pry tool to separate the cover from the screen.

In the Beo5 service manual I noticed that B&O used a standard TFT screen from Samsung. That's a standard product you might get off the internet. So if there's something wrong with the TFT screen + touchscreen layer, you might actually get a new one for, I don't know, say 50 bucks? That might be worth it. Just make sure you find a model number on the screen unit when the display module is disassembled.

The circled connector is for the display, the touch connector is smaller, but I have disconnected/cleaned and re-connected both, and still nothing. It seems the Touch is just dead..

/Weebyx

I have a couple of Beo6's with dead touch screens and I concluded that they were both hardware faults, so not fixable without replacement parts.

Regards Keith....

Weebyx
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Weebyx replied on Fri, May 29 2020 11:05 AM

Keith Saunders:

Weebyx:

manfy:

I've done some more digging and it seems that you may not be completely out of luck after all.

The official B&O marketing video shows some details that are very interesting.

This is the main board, ie. the motherboard of the unit and it is part of the display module. The bad thing about that is that the official replacement display module from B&O is probably prohibitively expensive. The good thing is that it shows the flex cable connector, which is a potential source of a malfunctioning digitizer (that is the thing that provides touchscreen functionality).
Beo6 uses a capacitive touchscreen and that is probably an integral part of the screen (as opposed to the resistive sytem used in Beo5). Since touch functionality is completely absent there are only 2 primary error sources: a contact problem between screen and motherboard or a damaged touch controller (the latter is possible but unlikely). Similarly, a complete malfunction of the transparent touch layers on the screen is rather unlikely.

So, if you're lucky, a simple unplugging and replugging of the flex cable might fix the whole problem. You only have to figure out how to disassemble the display module. I'd guess it works in a similar way as modern mobile phones. There could be some tiny screws somewhere at the base of the display and once removed you just need a pry tool to separate the cover from the screen.

In the Beo5 service manual I noticed that B&O used a standard TFT screen from Samsung. That's a standard product you might get off the internet. So if there's something wrong with the TFT screen + touchscreen layer, you might actually get a new one for, I don't know, say 50 bucks? That might be worth it. Just make sure you find a model number on the screen unit when the display module is disassembled.

The circled connector is for the display, the touch connector is smaller, but I have disconnected/cleaned and re-connected both, and still nothing. It seems the Touch is just dead..

/Weebyx

I have a couple of Beo6's with dead touch screens and I concluded that they were both hardware faults, so not fixable without replacement parts.

Exactly… There is one 100uf SMD cap that is located near the touch connector. Same type that dies in the IR path of many B&O IR receivers. I have thought about just replacing it and seeing if it makes any difference :)

Did you ever try to swap screens/PCB with a working unit, just to find out if it is the screen or PCB that dies ?

/Weebyx

BeoMotion
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BeoMotion replied on Fri, May 29 2020 6:03 PM

Anybody knows which capacitive touch interface chip the Beo6 screen is using? 
Often those chips are directly located on the flex cable that connects to the digitizer.

once you have the type you can try to find its data sheet and try to interface with it using an Arduino or whatever. Typically it’s just I2C along with reset, interrupt and power supply. 
if that’s not working it might be worth replacing the CPT chip which might got defective due to mechanical or electrical stress. 

Weebyx
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Weebyx replied on Sat, May 30 2020 6:25 PM

BeoMotion:

Anybody knows which capacitive touch interface chip the Beo6 screen is using? 
Often those chips are directly located on the flex cable that connects to the digitizer.

once you have the type you can try to find its data sheet and try to interface with it using an Arduino or whatever. Typically it’s just I2C along with reset, interrupt and power supply. 
if that’s not working it might be worth replacing the CPT chip which might got defective due to mechanical or electrical stress. 

It is this IC.

https://www.analog.com/media/en/technical-documentation/data-sheets/AD7147.pdf

/Weebyx

BeoMotion
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BeoMotion replied on Sat, May 30 2020 9:13 PM

Weebyx:

It is this IC.
https://www.analog.com/media/en/technical-documentation/data-sheets/AD7147.pdf
/Weebyx

okay, thanks. Good to know. 
Luckily still available. So if that’s the common problem here it can be easily replaced. 
It would just need a little further investigation to find out if that’s the root cause or not.
Other possibilities could be a broken flex cable or a damaged I2C port on the host processor. 

manfy
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manfy replied on Mon, Jun 1 2020 12:46 PM

Weebyx:

It is this IC.

https://www.analog.com/media/en/technical-documentation/data-sheets/AD7147.pdf

/Weebyx

No, that seems unlikely! The chip has only 13 sensor inputs, so at best you'd get a 6x7 matrix of touchscreen points and that's way too low for an acceptable touchscreen resolution. I'm quite sure that the AD7147 is the chip that provides the wheel functionality on the keypad. Just look at the "Typical Application Circuits" section at the end of the datasheet.

 

Weebyx
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Weebyx replied on Mon, Jun 1 2020 3:09 PM

manfy:

Weebyx:

It is this IC.

https://www.analog.com/media/en/technical-documentation/data-sheets/AD7147.pdf

/Weebyx

No, that seems unlikely! The chip has only 13 sensor inputs, so at best you'd get a 6x7 matrix of touchscreen points and that's way too low for an acceptable touchscreen resolution. I'm quite sure that the AD7147 is the chip that provides the wheel functionality on the keypad. Just look at the "Typical Application Circuits" section at the end of the datasheet.

 

None the less, this is the IC that is connected to the P400 connector, which is connected to the screen digitiser :) I am looking at the PCB right now, also the cable that comes from the touchscreen, has 13 connections that maps directly to the 7147.

/Weebyx

BeoMotion
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manfy:
No, that seems unlikely! The chip has only 13 sensor inputs, so at best you'd get a 6x7 matrix of touchscreen points and that's way too low for an acceptable touchscreen resolution. I'm quite sure that the AD7147 is the chip that provides the wheel functionality on the keypad. Just look at the "Typical Application Circuits" section at the end of the datasheet.

The number of cap sense inputs does not equal to the maximal possible touch points. Those values are not 1/0 but more like an analogue reading from multiple cells that the controller will then use for calculating the exact position. When placing your finger on the screen the value of multiple cells will change.
The click wheel most likely uses an optical encoder which is located on the interface board in the "ball".

manfy
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manfy replied on Tue, Jun 2 2020 7:03 AM

BeoMotion:

The number of cap sense inputs does not equal to the maximal possible touch points. Those values are not 1/0 but more like an analogue reading from multiple cells that the controller will then use for calculating the exact position. When placing your finger on the screen the value of multiple cells will change.

Good point. But it still seems an odd thing to do, repurposing this chip for touchscreen use when you have proven dedicated chips for that purpose. Synaptics seems to be a controller that is found quite often in high-end electronics for such applications since the early 2000s.

But well, the point is moot since Weebyx confirmed that the chip is directly connected to one FFC that goes to the screen and therefore it can have no other function than touchscreen decoding.
But - and that's a good thing - it does open the door for troubleshooting and even hacking the function of this touchscreen input. You'd need a good signal analyzer or digital scope for that though.

I find it hard to believe that the chip could have failed completely and I suspect a systematic problem just like a dead capacitor, bad solder joint or similar, which might interfere with the ongoing autocalibration procedure. The bias pin and the capacitor connected to it seems to have a crucial function for measurement and is worth looking at. 

I'd be interested to know the CPU model B&O used for the Beo6. Is it still the MC9328MXs from Freescale that they used in Beo5 or is it a later model? (The CPU is just above the large FFC connector that goes to the screen (that cable is for the RGB signal for the screen).
Is pin 8 on AD7147 connected to the FFC that goes to the digitizer? That pin 8 (ACshield) provides noise immunity for the measurement signal.

And my final question, did you find a model number on the LCD panel itself. This might be helpful for finding the specs and/or a potential replacement screen. Beo5 used a Samsung screen, LTV250QV but there'a absolutely no information available on the net about the Beo6 screen maker or model.  

 

 

 

BeoMotion
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The best way to start is just taking an oscilloscope and try to see if there is clock & data activity and a stable power supply.
Due to the good availability of the chip the next step would be replacing it carefully. While dead ceramic caps are very unlikely one additional thing could be replacing the single aluminum one. Even there I think a fault is pretty unlikely.

If that does not help chance are low breathing new life in the touchscreen.
I can't help here further as I neither have a Beo6 nor a broken screen. 

manfy
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manfy replied on Tue, Jun 2 2020 10:45 AM

BeoMotion:

The best way to start is just taking an oscilloscope and try to see if there is clock & data activity and a stable power supply.
Due to the good availability of the chip the next step would be replacing it carefully. While dead ceramic caps are very unlikely one additional thing could be replacing the single aluminum one. Even there I think a fault is pretty unlikely.

I fully agree with the first part. Measuring various pins on the chip with a scope can give you a good idea where the problem might come from.

I strongly disagree with replacing - or even ordering - the chip unless you have experience in SMT soldering and the right equipment for it. On Mouser it says that this is a 4mm CSP package (chip scale package) and without underheat and a temperature-controlled hot air pencil I see little chance of successfully getting a new chip mounted. Don't even think of just yanking it with an off-the-shelf uncontrolled soldering iron!
Replacing a 2-pin capacitor with a normal soldering iron and a high quality solder wick may be fine when you have some experience, but not a CSP package.

The second thing to try once you see that the digital signals are fine is to use a plain piece of flex cable and connect it to the digitizer zif-socket on the motherboard. This flex cable will act like a capacitive sensor and by gliding your fingers across that insulated FFC you might see a response from the touch controller. If so it would be a strong sign that the touch controller is detecting the change in capacitance and responding accordingly in which case you'd need to take a look at the ITO touch layer - or maybe the connection from the FFC to the ITO layers.

BeoMotion
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BeoMotion replied on Tue, Jun 2 2020 12:32 PM

manfy:

I strongly disagree with replacing - or even ordering - the chip unless you have experience in SMT soldering and the right equipment for it. On Mouser it says that this is a 4mm CSP package (chip scale package) and without underheat and a temperature-controlled hot air pencil I see little chance of successfully getting a new chip mounted. Don't even think of just yanking it with an off-the-shelf uncontrolled soldering iron!
Replacing a 2-pin capacitor with a normal soldering iron and a high quality solder wick may be fine when you have some experience, but not a CSP package.

The second thing to try once you see that the digital signals are fine is to use a plain piece of flex cable and connect it to the digitizer zif-socket on the motherboard. This flex cable will act like a capacitive sensor and by gliding your fingers across that insulated FFC you might see a response from the touch controller. If so it would be a strong sign that the touch controller is detecting the change in capacitance and responding accordingly in which case you'd need to take a look at the ITO touch layer - or maybe the connection from the FFC to the ITO layers.

Sorry, but I really don’t see where this should be a CSP package. Have a look at the datasheet. It’s a standard QFN with EP and 0.5 mm pitch.
I agree that you should only try to replace it if you know what you are doing. I’m working with embedded systems every day so might have forget to mention that disclaimer... If you are trained doing such rework it is certainly much easier and quicker than any other possibilities after confirming power supply and host activity. You can also probe the interrupt pin that should go low on every change.

In don’t understand the second part of your reply. The open end of the flex cable (which connects to the MCU board) only carries power supply and digital signals (either I2C or SPI according to the datasheet). Touching there won’t have any impact on the readings from the CPT panel. The other end of the cable usually is well sealed and hidden behind the frame so no way touching there either. You can debug caps sensors with oscilloscopes or spectrum analyzers...

 

manfy
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manfy replied on Tue, Jun 2 2020 1:57 PM

BeoMotion:

Sorry, but I really don’t see where this should be a CSP package. Have a look at the datasheet. It’s a standard QFN with EP and 0.5 mm pitch.
I agree that you should only try to replace it if you know what you are doing. I’m working with embedded systems every day so might have forget to mention that disclaimer... If you are trained doing such rework it is certainly much easier and quicker than any other possibilities after confirming power supply and host activity. You can also probe the interrupt pin that should go low on every change.

Unsure ...and maybe I'm a bit too cautious after having seen a standard leaded components PCB in a massacred state after an unnamed member in this forum tried to remove some resistors. Whistle  It's certainly doable to manually solder a QFN, but anybody who tries this for the first time on a working PCB should be aware of the process. At the very least, they should look at some QFN soldering videos on UTube and then assess whether they're comfortable doing this.

BeoMotion:

In don’t understand the second part of your reply. The open end of the flex cable (which connects to the MCU board) only carries power supply and digital signals (either I2C or SPI according to the datasheet).

No, I think that's a misunderstanding. The AD7147 is mounted on the motherboard and not on the flex cable. That's a perfectly fine design according to the manual of the eval board for this chip. So the flex cable actually can act as the actual sensor - that's the unique quality of this chip, the sensors can be realized with a single PCB layer since the excitation voltage is muxed into the measured signal. To simulate the matrix of the normal capacitive touch screen it would be best to use half the inputs as row electrodes and the other half as column electrodes....but well, I didn't want to complicate things.

Yes, the interface between the ITO layer and the flex cable may be hard to access. But it IS an error-prone source of problems. I don't know how the conductive ITO traces are bonded to the copper of the flex cable, but would guess it's done with conductive adhesive. If that connection fails, which could easily happen due to aging or rough handling of the unit, it might be fixed by reheating the right eges of the digitizer and then applying pressure in the hope that the electrical connections will be re-established.
Granted, that's a tricky process and should be the (very) last resort!

 

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