Removed circuit boards for paint now screen dead, No startup

[LazLong]

Hi all,

Got the M9 gimbals and wanted a repaint so I stripped out the components which were nicely handled, did the paint and installed the gimbals and plugged it all back in.

But no splash screen, no screen at all. No sound start up either. So checked voltage at switch which was fine. Checked ribbon cable to screen and the 2 connecting back/front and seem fine. Left it on for a bit and checked temperature of chip which was 31'c so it's getting power right? Swapped back the old gimbals as I was clutching at this stage to no benefit. All switches are checked and not pinched on by mistake and all cables are seated correctly and tight down. I did try without any cables at all as they really shouldn't be actually needed to boot right?

Don't really want to buy a new main board but will I have too?

Thanking you in advance

[MikeB]

With power off, try connecting the USB cable to you r PC. If the PC detects the "STM Bootloader", then you know the processor is OK.

Mike.

[LazLong]

No go on the USB but not plugged it in after the win10 upgrade until now.

ps it's a X9D+

[Kilrah]

Supposing you've got a Taranis Plus, did you omit to disconnect the battery before manipulating the ribbon cables? If yes you probably fried your mainboard by doing so.

[LazLong]

That should have been another ps from the start. Yes, the battery was disconnected before I split the case and not repowered until full assembly of the circuit boards.

That's why this is all so confusing. It's not like I have not removed the cables before with no issue and this was like doing exactly the same.

Thanks for trying.

[LazLong]

Supposing you've got a Taranis Plus, did you omit to disconnect the battery before manipulating the ribbon cables? If yes you probably fried your mainboard by doing so.

If that is the case, is there a way to confirm it? Other than it wont work. Is there a diagnostic I can run through?

[kalle123]

No go on the USB but not plugged it in after the win10 upgrade until now.

???

Did you connect USB with power off?

Did your pc show "STM Bootloader" in system information?

Try to use different USB port on your pc and try to use different usb cables ....

[Kilrah]

Another possibility is that a trace in a ribbon broke over time if you say you've removed/reinstalled them several times, so check for continuity of all traces from end to end and no short circuit between them - if that's OK and you still get neither power up nor USB connection then either the main voltage regulator or the microcontroller is shot.

[LazLong]

Yes

No. Yes I have check forums about the 'STM' issue and have tried several options listed with no success. As mentioned I have not plugged tx in before the issue and after Win10 upgrade. Yes, it used to work fine on Win7 (hope I anticipated most of the follow up questions )

Same cable i'm afraid, but different ports. Have used same cable on other devices and works fine.

Even if it did, I don't understand how this might help the LCD screen from showing boot-up, but I think I get the idea of getting into the chip to save any data (?) or that it might just be the screen that need replacing.

I just ordered a replacement anyway...

Thx