I had my dg834n up and running to see if it was still overheating with the case and part of the wifi shielding removed, the good news is that it didn't red light, so I'm going to try to remove the remaining shielding from the wifi card and fit a heatsink, or maybe a graphics card heatsink + fan.
Anyway, I had a quick look at the settings, crontab and NVRAM. I'd actually completely got rid of the crontab entry for the schedule (can't remember how I managed that), but I did have an entry for restarting the wifi at midnight exactly as above.
So far I've found if I set wifi schedule entries in the user interface for
all four of the SSIDs, with a time that I'm unlikely to be using the router, then I get entries for each time I entered in the crontab, but I no longer get the entry for midnight. When I turn off all the SSIDs that aren't being used and set the remaining to always on, the new crontab retains the new entries, but doesn't regain the one for midnight. As I see it, the firmware really should be removing crontab entries for a SSID that has the schedule disabled, and ideally they should find a better way of disabling a ssid by schedule without restarting the whole wlan to do it.
Here's my current crontab after a reboot of the router. I have set a different time for every entry for the purpose of testing then turned the schdules off on all of SSIDs, so I've now got lots of usr/sbin/rc sch_wlan restart entries - two for each ssid But no midnight ones. I'm guessing that if you were to set the same pair of times for every SSID, they'd only be one entry for each ssid or maybe just one after you switch schedule off for all of them.
# cat crontab
SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin
MAILTO=root
HOME=/
11 11 * * * root /usr/sbin/rc sch_wlan restart
15 15 * * * root /usr/sbin/rc sch_wlan restart
12 12 * * * root /usr/sbin/rc sch_wlan restart
13 12 * * * root /usr/sbin/rc sch_wlan restart
13 13 * * * root /usr/sbin/rc sch_wlan restart
14 13 * * * root /usr/sbin/rc sch_wlan restart
14 14 * * * root /usr/sbin/rc sch_wlan restart
15 14 * * * root /usr/sbin/rc sch_wlan restart
#
As you can see no schedule restart entry either - my nram setting is as follows -
# nvram get fw_schedule
name=1111111:0:0-24:0
#
I've somehow got an invalid stop time of 24:00 hrs

(possibly I set it directly) which must be the cause. This is probably not a good idea, as the syslog and ddns restart entries are missing as well.
I'm wondering if removing the following fields (name and value) from nvram after first turning off wlan schedule for all ssids might cure the wlan restart thing completely, I haven't tried it yet, so be careful and don't blame me if it bricks it.
wifi_if_on_sch_hour=11
wifi_if_on_sch_min=11
wifi_if_off_sch_hour=15
wifi_if_off_sch_min=15
wifi_if_on_sch_hour2=12
wifi_if_on_sch_min2=12
wifi_if_off_sch_hour2=12
wifi_if_off_sch_min2=13
wifi_if_on_sch_hour3=13
wifi_if_on_sch_min3=13
wifi_if_off_sch_hour3=13
wifi_if_off_sch_min3=14
wifi_if_on_sch_hour4=14
wifi_if_on_sch_min4=14
wifi_if_off_sch_hour4=14
wifi_if_off_sch_min4=15
Edited by AbandonShip (Tue 29-Mar-11 17:19:25)