Electronics > Repair
Trying to troubleshoot a main board with Rockchip RK3288 microprocessor
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fzabkar:
I'm just curious. What are the complete markings on the ACT8846 chip? Is there a "490" marking anywhere?
Yamin:

--- Quote from: fzabkar on February 17, 2020, 12:57:26 am ---I'm just curious. What are the complete markings on the ACT8846 chip? Is there a "490" marking anywhere?

--- End quote ---
There is no marking "490" may I ask what that means?
fzabkar:
There are different versions of the ACT8846 which are preprogrammed with different voltages and different power-up sequences for each specific SoC. The RK3288 requires the ACT8846QM490 version (see pages 3 & 34 of datasheet).
jboy32:
Hi all
First of all, happy new year 2022  :D
I'm owner of a 2nd hand HR Pedalboard, and facing a known issue on this pedalboard effect that is related to USB.

USB connect to my laptop has been working twice, but since 2 weeks, no possibility to connect, I have checked the USB wire with some others, tested on 3 different laptop with different OS running on, and different USB port. I still doesn't work.

I have been reading different forum speaking about this known issue where, Headrush sometime fix it by changing the motherboard, or you need to buy a new one an fix it yourself ... when you see the original price of the pedalboard and the cost for a new motherboard, that is just amazing  :-[

Mine still power up, but I can't add new IR or RIG because of the USB issue ... I have been looking inside the main motherboard that you are speaking about on this forum, and I'm wondering what could be the 2 buttons (Reset / Recovery ) ?

jboy32:
Some updates on my investigations

After having unmounted the pedalboard, I found a motherboard that looks like the one of MPC Live.
I have connected a wire Serial to USB and use TeraTerm.

I have errors in the output of the terminal connected during the boot sequence :
...
001: dwc2 ff540000.usb: ff540000.usb supply vusb_d not found, using dummy regulator
001: dwc2 ff540000.usb: ff540000.usb supply vusb_a not found, using dummy regulator
001: dwc2 ff540000.usb: dwc2_check_params: Invalid parameter lpm_clock_gating=1
001: dwc2 ff540000.usb: dwc2_check_params: Invalid parameter besl=1
001: dwc2 ff540000.usb: dwc2_check_params: Invalid parameter hird_threshold_en=1
...
001: usb5537 1-002d: Failed to write config file
001: usb5537 1-002d: failed to switch mode: -6
...

I have then a prompt for login, it is a linux running, but no chance to log into with root even with blank password  :(

Also when I put the headrush in Update Firmware mode from the screen touch (same as starting with recovery button on the motherboard), in the output of the terminal, I have this message

Starting fastboot...
ERROR: usb5537_write_config: failed to write config file: ret=-121

at drivers/misc/usb5537.c:69/usb5537_write_config()
ERROR: board_usb_init: failed to probe usb5537@2d: ret=-121

at board/inmusic/az01/az01.c:525/board_usb_init()
otg_phy_init

I don't know if that could be a software issue or hardware issue for the moment but if those information can help to investigate let me know  :) 
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