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geekhack Community => Keyboards => Topic started by: idk420 on Sat, 03 April 2021, 17:43:09

Title: RK61 firmware or chip problem
Post by: idk420 on Sat, 03 April 2021, 17:43:09
Hi. I have a RK61 keyboard and some time ago it just stopped working. '

Some info:
>Keyboard charges but the LED that inform you that the keyboard is charging does not appear during charging.
>I've spoken to RK support and for some reason the keyboard can't be forced to change its firmware.
>When the keyboard is plugged via USB the windows shows prompt that it cannot recognise the USB device and in devices menager there is a following info: A request for the USB device descriptor failed.
>Any method to prevent windows blocking the device does not work.
>It has HID hfd2201kba chip inside which is becoming very hot when the BT is on, same thing when I try to force boot the keyboard.
>The keyboard shows signs of life because the random keys backlight works some time, when I try to force boot - the backlight works but windows block the device.

Questions:
1. Is there any possible to prevent windows blocking the device? Any of method that i found online does not work.
2. Is it possible to replace the hfd2201kba chip and where can i get the newone?
3. Any advices how can i try to solve the problem?
Title: Re: RK61 firmware or chip problem
Post by: suicidal_orange on Sun, 04 April 2021, 04:23:15
1 - Windows asks 'what are you?' and the keyboard replies in ancient Greek.  Unless the chip has another mode (called bootloader mode on the Atmel chips used in DIY boards) it's only capable of saying one thing, and Windows doesn't understand it.  If you haven't already try another cable and USB port to make it try harder but I don't think it will help.

2 - It's a chip, if you have the tools and skill you can swap it physically if you can find one.  If the firmware updater works with an empty chip or there are pads broken out for other flashing methods it's an option.

3 - I've failed to find anything about this chip which is why these answers are vague.  Is this the typical bluetooth PCB where the keys are controlled by one chip and the bluetooth is on an extra stuck on PCB?  Which chip is hot?  A picture would be useful, ideally one showing the text/logos on the chips and a few keys to see where they're connected :)
Title: Re: RK61 firmware or chip problem
Post by: Leslieann on Sun, 04 April 2021, 05:38:05
I would also say look at the cable but if that doesn't fix the problem I would recommend just scrapping it.

While you may be able to replace the chip, what caused the chip to go bad? You could go through all the trouble to replace the chip only to plug it in and find that the new chip fried as soon as you plugged it in. The fact that it's getting really hot makes this a concern. If it's cheap enough and you have the skills and tools, go for it but most people lack the tools to pull this off.
Title: Re: RK61 firmware or chip problem
Post by: idk420 on Sun, 04 April 2021, 08:19:26
1 - Windows asks 'what are you?' and the keyboard replies in ancient Greek.  Unless the chip has another mode (called bootloader mode on the Atmel chips used in DIY boards) it's only capable of saying one thing, and Windows doesn't understand it.  If you haven't already try another cable and USB port to make it try harder but I don't think it will help.

2 - It's a chip, if you have the tools and skill you can swap it physically if you can find one.  If the firmware updater works with an empty chip or there are pads broken out for other flashing methods it's an option.

3 - I've failed to find anything about this chip which is why these answers are vague.  Is this the typical bluetooth PCB where the keys are controlled by one chip and the bluetooth is on an extra stuck on PCB?  Which chip is hot?  A picture would be useful, ideally one showing the text/logos on the chips and a few keys to see where they're connected :)

1. Different cabble/USB port - same issue.
2. I can't find another chip, or i don't know where to look for it.
3. Yes it is a typical keyboard with soldered switches, one chip "hid hfd2201kba" and extra module with bluetooth.

Photo of whole PCB and the HID chip that is becoming very hot but only when the bluetooth is on: https://ibb.co/84THvK6 https://ibb.co/7NNQFZR

I've had similar issue with bigger sister of this keyboard - RK68, but the RK68 allowed me to force firmware update and this one not. The symptoms are the same in both cases, but when I was plugging RK68 to the PC there was no error that windows cannot recognise the device.

To force firmware update - I need to connect those two little holes in PCB right next to the HID chip with some conducting material like bent paper clip. When I connect them the backlight of the keys is working but winows still cannot recognise the device and HID chip is quickly becoming very hot.