On Saturday, the CMOS battery died on my second 7104.
It blanked the TDS7104 screen and kept me from getting into BIOS.
Battery was dated 1995.
Replaced battery.
Access the VGA connector in back with separate monitor.
You need to install KILLCMOS application on floppy MS-DOS start-up disk.
I used a 2SHD 1.44MB High Density floppy on a XP OS machine.
When formatting disk there is a check for create MS-DOS disk.
Online I downloaded a KILLCMOS program. (
https://www.majorgeeks.com/files/details/killcmos.html)
Extracted file and installed on floppy.
Boot from the floppy type dir in the command line.
Find and and run KILLCMOS .
CTRL Alt Delete
F2 Setup
Your BIOS is now accessible.
Change config of BIOS to default settings.
Change Display to PCI
Save and restart oscilloscope.