The problem began when both the green WiFi light on the DG834N (v1) ADSL/router stopped functioning and the ability to see the SSID being broadcast ceased. It seemed nothing had changed and during transport from one location to another it had simply died.
To begin with I flashed the latest firmware to the device. It is really important to do this via a wired connection to these devices; often if you perform the operation via wireless the upload of the firmware partially fails and the device ends up becoming a brick. You have been warned!
With new firmware I rebooted the device and at this point the WiFi light turned green. I congratulated myself and expected to find the SSID being broadcast as per normal. It was not to be however, and many hours were about to be spent solving the problem.
I tried many resets – including a hard reset. To perform a hard reset hold the reset button in for 20 seconds with power, continuing to hold the reset button but remove the power for 20 seconds, and finally connect the power while still holding in the reset button. So: 60 seconds holding in the reset button, 20 powered, 20 unpowered, 20 powered. If this reset works properly the power LED will flash between red and green.
After a phenomenal amount of searching the internet I found a few clues to the issue and eventually solved it.
The WiFi component on this model is a plug in module that can sometimes become loose. Open the case, pull the module out, and re-insert firmly. The module is instantly recognisable by the two antenna wires that attach to it.
Note: There are two torx screws that need to be removed underneath at the base and also two underneath the large sticker label at the rear of the unit.
Apparently the chipset on this model is notorious for heat generation eventually leading to failure. A future mod for this device could be using a dremel to carve out a hole in the chasis and subsequently add a fan to improve airflow.
With the simple plug in antenna arrangement these could also be replaced; however I have had no issues with WiFi performance.
The power supply that comes with these devices are also reputed to be quite underpowered. Mine seemed quite heavy duty so I dont think I will need to replace it unless the addition of a fan increases the current draw too much.