I’ve got an IBM PC XT (5160) of unknown condition. The case was aged, but the motherboard looks very good.
Because I don’t have a monitor for this machine, first I wanted to do a POST - power-on status test. You can know if the machine is working or not by healing beeps from a speaker.
I’ve connected it to the power supply and the speaker, and power the machine on. It looks like it is working. I am hearing a long beep followed with two short beeps (LONG-SHORT-SHORT). It is likely an error telling the video card is not found (and I haven’t installed it and is expected). This means the CPU is running and the BIOS ROM is read successfully.
I’ve purchased a new CGA card from ebay. I wanted something known to work as a reference.
With the new CGA card, initially the POST error was the same (one long beep and two short beeps). I knew the DIP switches matter, so I’ve reviewed them and changes them to 01110111 indicating I am using a CGA card.
With the new DIP switch settings, it is making some progress and I got two short beeps only. According to this page, an error should be shown on the screen!
NEXT: I don’t have a monitor that can show CGA output. I don’t have a keyboard either. Get these to see the error on screen.