Q X7S bricked after power off with still connected receiver

Hardware help and support for the FrSky Taranis
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jUmPeR
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Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Hi, all.
My qx7 is 3-4 monthes old. From the begining of use I flashed OpenTX version 2.2.2 with bootloader.
Nothing changed except battery, I'm using 3x18650 = 12.6V. This mod was made one week ago and everything was fine for the last week(I flied every day).
Yesterday, between flights, I powered off my TX while quad was powered on. TX asked me something like that "Receiver is still connected, are you sure?" I accept warning and turned off the TX. And after I changed battery(3-5 min.) in the quad I can't turn on my TX anymore. No led under the power button, no display backlight, nothing but only slight click from speaker when pushing power on button, and another slight click from speaker when pulling finger off.
When I came home tried to connect TX to PC but with no luck. No new devices in Control Panel or in Zadig, just same slight click from the speaker.
After disassembling radio on first two looks) everything is fine and no hot elements(tried to touch with my finger).
Tried to disconnect radio module and power it on, but get no reaction at all - no click sound from the speaker.
Also tried eject, format and use another sd card. Tried different USB ports on notebook. I have only one USB cable now, but I'm sure that it is OK. System is Windows 7. Can't try another PC because I'm in travel, and will be for one week more. Also don't have a multimeter at the moment, will try to find out one soon.

Gramps50
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Re: Q X7S bricked after power off with still connected receiver

Post by Gramps50 »

Did you by chance charge the TX battery to see if that made a difference?
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Also want to ask about main board - I think that qx7 and qx7s boards are similar, am I right?
And does anyone know where is the power cycle part of the board and what elements I must test at first?
P.s. thank you.
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Gramps50 wrote: Tue Oct 02, 2018 3:51 am Did you by chance charge the TX battery to see if that made a difference?
Thanks for answer. Battery is fully charged 12.6V, and also tried battery from my fatshark googles, it has 2s connector with 8.4V but nothing changed.
Carbo
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Re: Q X7S bricked after power off with still connected receiver

Post by Carbo »

Usually it can not be bricked. What happens, if you disconnect battery and connect TX to PC?

jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Carbo wrote: Tue Oct 02, 2018 9:02 am Usually it can not be bricked. What happens, if you disconnect battery and connect TX to PC?
Nothing happens. No new devices in Control Panel or Zadig. Also tried with trim buttons in bootloader mode - same story. I just can hear slight click from TX speaker when inserting USB.
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

I'm think about ordering new main board, but not sure about x7s version. Is boards of x7 and x7s same? Asking because fast search on eBay and bangood don't give me any x7s versions, only x7 rev. 0.4
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

I think the only one difference of the main boards of x7 and x7s is soldered Bluetooth module on x7s.
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Kilrah
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Re: Q X7S bricked after power off with still connected receiver

Post by Kilrah »

That's correct.
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

So I'm at home now...
Made some tests:
When plugged from USB MCU power is OK - 3.28V
Tried to connect and flash with stlink, but I can only read and erase memory, but having problem with writing - got an error "Programming error @ 0x08000008!"
And after getting this error I can see that something was written in previously empty flash, but not 100% same content of "opentx-x7-lua-sqt5font-en-2.2.2.bin" - I can see some differences(please see attached screenshots).

Any thoughts about why flash can't be written?
Is it possible that reflowing the MCU can help?


p.s. still no reaction while connecting throug USB...
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Screenshots
Attachments
IMG_20181008_044840.jpg
IMG_20181008_044845.jpg
IMG_20181008_044907.jpg
IMG_20181008_044821.jpg
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Voltage on BOOT0 is 3.3V and it's connected through R418(7.3K) to the ground.
p21marola
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Re: Q X7S bricked after power off with still connected receiver

Post by p21marola »

Hi all
I have an x7s with a few days of use and exactly the same problem. From what I have been able to see looking for solutions, this problem is quite common in these transmitters and this thread is the closest to a solution I have seen so far.

The proven facts are the following:
The station works correctly, but suddenly at some point it stops working.
Pressing the power button only sounds a click on the speaker and nothing else happens.
When connecting it through the USB port it does not appear on the PC. The only thing that happens is the same click on the speaker, which for me rules out a problem in the cables that feed the main board.
Everyone has verified that the battery is fully charged, so this is ruled out.
Removing the small battery from the main board and the main battery for a few minutes does not give any results.

My assumptions are:
The problem is on the main board, is it a hardware or firmware problem?
It is a cheap transmitter so it is probably more profitable to replace it with a new one than to try to repair it by buying spare parts, so looking for a solution is more a matter of pride. I'd rather have a cheap transmitter than an expensive brick.

The questions are the following:
Is there anyone who has managed to repair this problem in any way?
Replacing the main board?
Reflashing the bricked main board in some way?


Thank you all.
"I apologize for my English, the fault is google translate;)"
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Hi, p21marola.
I think the easy way is to change mainboard, but if you have air rework station and some skills reflowing main MCU( STM32F205VET6) can help. I ordered new stm32 chip and diode(because find out it is dead) and hope that changing main chip will resurrect my radio.
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

So I reflowed new stm32 mcu and q501 double diode and now I have got stm32bootloader in windows device manager.
Now I can flash firmware through opentx companion, but cant power on the receiver.
I'v got no reaction at all when pressing power button, no power button led or lcd.
Any thoughts where to go next?
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

q501 is NOT BAW56 double diode!!!
after I resolder q501 back the TX powered on! Yeah! I'm so happy. :)
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jhsa
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Re: Q X7S bricked after power off with still connected receiver

Post by jhsa »

It looks like someone is saving on solder :) Or something is not going well in the PCB fab and assembly :o
They need a better quality control...
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p21marola
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Re: Q X7S bricked after power off with still connected receiver

Post by p21marola »

Good job @jUmPeR, awesome, bravo.....

As you said in a previous post, it requires certain skills but I am aware that I do not have them. The last processor I soldered, was a Zilog Z80 in the decade of the nineties. So I bought a new QX7. Meanwhile I do not give up on the QX7S, I downloaded the microprocessor data sheet. I have removed the dust from my old multimeter and this weekend I will dedicate myself to verify if there is power in all the processor pins that need it.

I hope that the micro is not damaged. Based on the experience and how you repaired yours. I think maybe it's just a desoldered component and if I can locate it, I'll try to solder it.

If I can not find anything, I will try to apply the method shown in this video: :D
https://www.youtube.com/watch?v=8Xanr4jkmEc

If I finally get positive results (something I doubt) I will tell you.

I repeat what has been said, good job, very good job and thank you.
jUmPeR
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Re: Q X7S bricked after power off with still connected receiver

Post by jUmPeR »

Thank you, p21marola!
I think you can try to check power only on few of the dedicated processor power pins, because, I'm sure, they are shared.
Check that you have 3.3 volts on cpu dedicated legs with connected through USB to your PC(and without TX battery).
About baking... Maybe you can order new CPU and try to find someone in your area who can reflow it? It's not too hard. Or you can try to use usual heated gun(but be aware of strong air flow that can blow away small smd components from the main board) to remove the CPU, and then sodler new one with usual solder iron(it's goot to that iron can be regulated)

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