Solved DWC suddenly shows only a blank page.

[Crosswire]

I have a 3D delta printer, not made by me, that suddenly lost the DWC web control interface, a web page is served but only as a blank white screen.
The printer seems to work otherwise, it is accessible from the local panel and the USB port.

I have not changed or updated anything on this printer.
Unfortunately I don't have a backup of the SD card.
The SD card is still readable.

I suspect I should replace some files on the SD card, but unsure which ones.
What can I do?

From the serial interface:
FIRMWARE_NAME: RepRapFirmware for LPC176x based Boards
FIRMWARE_VERSION: 3.3.0_14 ELECTRONICS: LPC176x
FIRMWARE_DATE: 2021-12-21 12:32:42

[jens55]

@Crosswire, don't know if it is related but on occasion I also get a blank page. It resolves itself quickly (might take 2 or 3 reloads). Today I had a blank page that did not resolve itself but I had no trouble with the same page on another computer (it was already loaded).

[Crosswire]

After much browsing, I found this in the Duet3D documentation:

If the web interface is not working, then move the SD card to a PC, delete or rename any existing /www folder, create a new one, and extract the contents of DuetWebControl.zip into it. Do not unzip the individual .gz files, leave them as they are on the SD card.

Indeed, that brought the DWC web UI back to life!

[gloomyandy]

@Crosswire Glad you got it fixed, you may want to think about getting a new SD card (as your existing one may be on the way out), at the very least make a backup copy of the SD card contents on your PC just in case!

[Crosswire]

@gloomyandy Your advice is taken!

The old SD was 128MB in size, so probably not that fresh.