# Led0 not blinking

**URL:** <https://forum.sierrawireless.com/t/led0-not-blinking/5588>\
**Category:** Open AT\
**Created:** [May 6, 2012, 11:24am UTC](https://forum.sierrawireless.com/t/led0-not-blinking/5588 "2012-05-06T11:24:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![luciano](https://avatars.discourse-cdn.com/v4/letter/l/f05b48/32.png) [@luciano](https://forum.sierrawireless.com/u/luciano)\
**Post date:** [May 6, 2012, 11:24am UTC](https://forum.sierrawireless.com/t/led0-not-blinking/5588/1 "2012-05-06T11:24:35Z")

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I am working on a project with Q2687RD.  
I have made a card with the Q2687RD and apparently seems to work, receives and sends SMS and i can load and run the various examples of code, i can sed and receive AT commads with the terminal.

There are two things that I can not run:

1. The LED0, even if the module is registered to the network, do not blink. The LED is connected between the LED0 output and through 470R to VBATT and the katode is connected properly.

2. When I try to download the firmware with DwlWin, operation strart end stops after the first stage of the bootloader download.

If I move the module onto the SiWi evaluation board everything works fine.

So, I think that is an error on the card, does anyone have any idea?

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**Author:** ![awneil](https://avatars.discourse-cdn.com/v4/letter/a/49beb7/32.png) [@awneil](https://forum.sierrawireless.com/u/awneil)\
**Post date:** [May 6, 2012, 2:52pm UTC](https://forum.sierrawireless.com/t/led0-not-blinking/5588/2 "2012-05-06T14:52:59Z")

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> [@luciano](#):
>
> If I move the module onto the SiWi evaluation board everything works fine.

So you need to look very carefully at the differences between the Eval Board and your board ❗

In particular, check power supplies and grounding:

> [@FAQ forum/wiki?](https://forum.sierrawireless.com/t/faq-forum-wiki/3491/13):
>
> Yes, I’ve had such issues myself! It’s not just the PSU itself - the connections to the module (especially ground) need to be absolutely “solid” Example: [viewtopic.php?f=123&t=5693&p=23827&hilit=vbatt+line+too+narrow#p23826](https://forum.sierrawireless.com/viewtopic.php?f=123&t=5693&p=23827&hilit=vbatt+line+too+narrow#p23826) This is because all GSM devices have a very high supply current peaks - Wavecom quote over 2A! open_mouth Edit: Just noted that I have already mentioned “[Module Grounding](http://www.wavecom.com/modules/movie/scenes/forums/viewtopic.php?f=7&t=3766#p15545)” in an earlier suggestion in this thread!

> [@FAQ forum/wiki?](https://forum.sierrawireless.com/t/faq-forum-wiki/3491/8):
>
> [viewtopic.php?f=5&t=3941&p=15544#p15544](http://www.wavecom.com/modules/movie/scenes/forums/viewtopic.php?f=5&t=3941&p=15544#p15544)[viewtopic.php?f=21&t=3950&p=15542#p15542](http://www.wavecom.com/modules/movie/scenes/forums/viewtopic.php?f=21&t=3950&p=15542#p15542)