Hello again,

I recently came into the possession of an Osborne 1 portable computer that I have been attempting to repair as it appears to not be working properly.

I had the machine fully disassembled, thoroughly cleaned, retrobrited, and I replaced the RIFA capacitors in the power supply which are a known point of failure but it seems to be acting the same as before I did anything to it. When I power it on, there is a brief beep from the internal speaker and the lights on the floppy drives flash when this happens and then nothing. When I power it back off, I can hear the CRT make a little whizz noise that makes me thing it is getting power but there is no image showing up. I played with the brightness and contrast and let the CRT sit for a bit as I know these old things sometimes need to warm up, but still no image from the screen.

There is also seemingly no activity coming from the floppy drives, pressing keys on the keyboard doesn't seem to register at all, and the reset button doesn't do anything. Does anyone know what the issue could be? I've heard that the power supply is prone to failure on these machines and mine may need more work (I already have more replacement caps) but I want to be certain before I proceed further.

Any help with this topic is greatly appreciated.