I just bought a german Atari 1040 STF, and am totally newbie on the platform.
The seller warned me that the floppy drive is broken but otherwise the computer should work properly. I understand that without the drive the boot process should take longer, but still complete. I also understand that all STF models should be able to boot from the ROM.
When I turn on the computer, the screen goes white momentarily, and it blackens a second later. It might be my imagination, but I think it rapidly fills the black downwards, so it does not look something turning off, but actively colouring the screen black progressively.
After that, the screen keeps on black forever, even after the machine gives up accessing the floppy drive.
If I reset the computer, the screen gets white and after that it gets washed with a plethora of colourful vertical lines, and does not go black.
I plugged a speaker in the audio output and found out that the key press beep is working, so it seems that the machine is alive, despite not showing the screen properly.
I did not open the case yet, but am not afraid of doing so.
Any tips on how to start diagnosing the problem?
Intellivision 1, Intellivision 2, Intellivision Sears, MSX1, MSX2, MSX2+, MSX2+ FPGA,TI99/4A, Amiga 500, Atari 1040STF, Exato Pro (Apple II Clone), TK2000 (Apple II Clone), TK85 (ZX-81 Clone), waiting for my Spectrum NEXT.