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Topic: fan on the 3.3V serial line

The content of this topic has been archived on 6 Apr 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

my cheap dlink dsl-500g is rebooting every day because of heat... I already ordered some generic heatsinks from china to glue to the bigger ICs there

but in the meantime, i was wondering if i could just plug a 3.3V fan i have laying around on the serial line pins.

is that ok? too dumb?

(Last edited by gcbwrt on 25 May 2012, 02:05)

Hi gcbwrt,

Not a good idea!
Ponder it for a second. To run the fan you will pull even more current causing the router power supply to run even hotter.
If it draws to much current it could blow something inside.
Also connecting the fan to the 3.3 volt rail may cause impulse noise issues on the router chips, etc.

Use an external power supply (5 volt or 12 volt depending on the fan requirements).

~john

thanks!
i was [wildly] guessing that the extra current draw would only impact the power supply components, not affecting the heat on the processing parts

and i confess i know nothing about impulse noise so i will assume it will happen.


would it be less dumb if i tap directly on the power supply connectors? i have others power bricks that can supply over 1/2A of what the modem pulls currently, with the same voltage.  ..even thought then i would have to mod a 12cm 12v fan i have around in the 10cm case smile

(Last edited by gcbwrt on 14 May 2012, 20:02)

Hi gcbwrt
If your wall power plug type power supply can push enough current then you may get by by using the (assuming +5 Volts) inside the router.

But I suspect you have an equal amount of work which ever route you go.

Why risk your router any further?....I'd go with the external power supply and mod as required.

Best of luck.

~john

OK, i ditched the fan idea so far, but still need help.

the modem still hangs after some time once a day. always near some random full hour...  i still think this is some hint. usually from 4pm to 9pm. but i couldn't get a real pattern other then always being between +/-10min from a full hour.

I attached the heatsinks a couple weeks ago. they still get hot, but do not burn my finger almost instantly as before. seems to have helped.

shame shot:
https://lh3.googleusercontent.com/-mB2tvt79Jqc/T77W2CG0OoI/AAAAAAAAAhw/53If5j41u58/s800/IMG_20120524_174739.jpg

I thought i could use openwrt on this... but i don't think the cpu supports it. chip says "conexant gs8120-174-008d b0"

I do have an actiontec GT710D but i'm not having luck getting it to run with openWRT as a dsl modem... so i have to soldier on with this one a little longer.

any idea how i can try to debug what's happening?
i can access it's viking thingy via telnet.

it seems to have serial support, judging from the 6 1mm pins in line, but connecting a serial line converter to it makes the modem hang on startup (since i do not know which one is PIN0, i tried both ways, both they hang with one or another LED on and no activity) they may be mixed for all that i could find ( nothing smile but i will not try all the combinations as the 2 i tried was already risk not knowing what that port is about. big_smile

So, i'm guessing my best bet is the viking shell.

i've found a bunch of pages describing it, but all of them talks about shells much, much, much more capable than what i have. mine is missing most of the commands those pages mention.

help give me this:

$help
Command        Description
-------        -----------
alias          To Alias a command                           
apply          Apply configuration/image file               
commit         Commit the active config to the flash        
create         Create a new entry of specified type         
delete         Delete the specified entry                   
download       Download a file on to the Device             
exit           To exit the CLI shell                        
get            Display info for the search                  
help           Provides help                                
list           List files                                   
modify         Modify information for specified entry       
passwd         To modify user password                      
ping           The normal ping command                      
prompt         Change the user prompt                       
reboot         Reboot the device                            
remove         Remove file                                  
reset          Reset info for the specified entry           
size           ATM Sizing Information                       
traceroute     The normal traceroute command                
trigger        To set trigger                               
unalias        To undefine previously defined alias         
verbose        Switch ON/OFF the verbose mode

the initial message for the shell is:

                         *******************
                         Welcome to Viking  
                         *******************

Software Release R2.01.B05.TF(030917a/Y.1.28.150)
Copyright (c) 2001-2003 by D-Link, Inc.

login:

Do i have any hope of finding out if the problem is on the modem or the dsl with this equipment?

(Last edited by gcbwrt on 25 May 2012, 02:20)

My DLink DSL-300T (looks like a similar motherboard) worked fine for a year or so, and then started rebooting itself daily. It then became a more consistent problem. Unfortunately, the quick and easy solution was to get one of those little dumb (no intelligence) SpeedStream modems used for $2, and take care of the PPPoE authentication on my router instead.

With regards to OpenWRT on that CPU, this thread discusses it.
This page discusses what appears to be a rebranded DSL-500g. It goes over pinouts and such.

(Last edited by Shadyman on 18 Jun 2012, 08:16)

The discussion might have continued from here.