Forum : ST7/STM8
Original Post
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February 23, 2011 - 9:08am
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Hi, My name is jae Hyun My office haved 5 rlink. Suddenly one R-link didn't operate. So, I compared another R-Link in PCB. I found difference of two PCB.
What is that ? Would you answer me please? |
Hi,
What difference did you find between the PCBs?
How does the failing part fail? (which operation? which error message?)
Are you sure that your target board and connection is correct?
It takes quite a lot to burn a RLink, and you should understand what happened to yours before repairing it or using other samples on the same target board.
Burning RLink usually results from target power not isolated from mains (RLink is connected to GND through USB and PC) or from powering a non-5V-tolerant board using the "PW-5V" jumper of the adapter. Is this your case?
Best Regards,
Vincent
Only When i connected r-link that have trouble to pc, system manager of PC didn't display connected.
When another r-link connected to PC, displayed r-link to pc connected.
(I didn't connect target borad.)
When trouble R-link connected to PC, ST662A 8 pin appear 4.7V. Though another r-link appear 0V.
Yesterday, I used r-link. I did debug and download at my project.
But when I initially used r-link today, r-link connected error. navertheless I changed adpat borad, didn't debug and download. I checked system manager. Result I know that PC isn't cognize r-link.
I changed marked part at picture between normal r-link to trouble r-link. As soon as trouble R-link displayed system manager of PC to connected. and R-link did operate(debug and download).
what is part number in picture?
Hi,
Here is the reference of the component:
74V1G04CTR SOT323-5L
If it is burned the USB connection cannot work, just like you describe.
However, as I already stated, you should refrain from simply replacing it and then forgetting about it:
This component doesn't burn easily, and that usually happens following some incorrect connection to or on the target board.
The fact that "it works" does not prove that the connection is correct and harmless to the hardware in the long term.
For example if you send the RLink's 12MHz clock to a board that has its own clock, or if you send RLink's 5V power to a board that has an external power, or that is not 5V-compliant, or if your target boars is not properly isolated from mains. In all these situations, the system can appear to work but after some time you will see physical damage to some components and it will start failing without notice.
So you should really try to understand what happened before going on. We can help you on this but for that we need information on your target board...
Best Regards,
Vincent
Hi,
I changed part that you informed. Result, R-Link connected to PC.
I used R-Link at my projects.
Thank You, Vincent