Weird stuff here as well, not figure it out yet.

My oldest computer is a Multitech MPF-PC, 8088 IBM PC clone. It's got onboard fdd controller and a 360fdd attached, and an 8 bit ISA mfm controller with (if I remember the type correctly) 10MB Shugart SA712 hard disk attached.

Trying to boot from floppy drive with ms/pc DOS version 2.11, 3.1, 3.3, 5.02, 6.22 results in an error: DIOS.SYS not found.
Can press any key and the computer tries to boot again with the same error.

Trying to boot from floppy with cp/m results in booting, but a halt on I/o conflict.
Ctrl alt del will reboot as expected, but that's my only option from there. Need to fiddle with some motherboard switches I guess.

Prepared the hard disk with PC DOS 5.02 in another machine (ofc with its own controller), and the system will boot to DOS and command prompt... But does no longer respond to the keyboard.

Eventually I placed a head park command in autoexec.bat to secure the drive when I have to turn it off. Something I have to get onto some day.

Mister Xiado wrote on 2020-06-25, 10:28:

The only accidental good fortune I've had was when I decided to restore my Goldstar 3DO years after ordering a replacement CDROM laser assembly not made specifically for the 3DO. Right after I disassembled the system and the drive tray to replace the laser, I randomly happened upon a page talking about replacing laser assemblies, warning that there is a solder bridge that must be opened before installation. It's soldered to prevent ESD during shipping, but apparently this isn't common knowledge. I removed the solder bridge, installed the assembly, and the system plays discs without issue now.

Ha, that sounds familiar! A friend of mine wanted to repair his €1000+ high-end SACD player from Sony, he ordered a rather expensive laser assembly and it didn't work. He got another one and it didn't work either. He junked the whole lot (including the player itself) and a couple of days later found out about this solder bridge that had to be removed 😁

ShovelKnight wrote on 2020-06-25, 14:35:

Ha, that sounds familiar! A friend of mine wanted to repair his €1000+ high-end SACD player from Sony, he ordered a rather expensive laser assembly and it didn't work. He got another one and it didn't work either. He junked the whole lot (including the player itself) and a couple of days later found out about this solder bridge that had to be removed 😁

Oh God, that's a big OOF. I've got a Sony receiver that doesn't like HDMI, and regularly pops the audio when used for analog or digital, likely due to the previous owner abusing it. I won't trash it, because maybe some day, I'll find that I just need to replace a couple capacitors or something simple.

The summer 1999 me and one of my best friends built two more or less identical computers. Asus P5A, K6-2 450 and 128mb ram and a really ugly case from Asus.

My computer was running really good, stable (ehum..) and no problems at all. My friends computer had some really bad issues with random reboots or just a black screen happening randomly.

We swapped most parts a few times, got a new motherboard but nothing helped. A few weeks later the problem was found... the reset switch was broken. Unplugged the reset button and no more problems appeared 😀

I had an issue where when you first turned on the 386 pc it did read floppies for about 15 minutes and after that it stopped reading the floppies and gave just errors, so if I wanted to transfer data from floppies to hard drive I had to do it immediately after I turned on the computer. Never really figured out what was causing that exactly.

Baoran wrote on 2020-06-25, 16:54:

I had an issue where when you first turned on the 386 pc it did read floppies for about 15 minutes and after that it stopped reading the floppies and gave just errors, so if I wanted to transfer data from floppies to hard drive I had to do it immediately after I turned on the computer. Never really figured out what was causing that exactly.

Sounds like a thermal problem to me.
Old mfm hard disks had their problems with alignment when heating up to much. Simply because the platters expanded and the stepper did not go with it.
It sounds plausible to me that your drive was assigned around the edge of usability and when warning up crossed that line. Main difference is the platter didn't expand but the guidework from your heads.

Oetker wrote on 2020-06-24, 17:25:

appiah4 wrote on 2020-06-24, 17:07:

Doom's setup menu makes a short beep through the PC Speaker whenever you select a menu item. Funny, isn't it? You forget about it until it matters.

Looks like my PC speaker is broken then, haha.

Apparently my system doesn't have PC speaker support, only a built-in speaker for use with the onboard sound chip. Kind of a bummer.

Had a problem with system not starting once. Turned out the low quality case, AGP video card and motherboard together made the video card sit just slightly too high in the slot. Loosening the thumbscrews on the AGP port fixed it.

Had a problem with a HDD just locking up when I copied from a floppy. I narrowed it down to a single file, that I chopped up and then looked at in a hex editor. The part it had issues with was a large section of FFh's. Scratched my head, virus?. Anyway, turned out that this early MYLEX SCSI controller does not provide termination power. Luckily the HDD was a similar vintage and had a jumper for Term power. Fixed, and works like a charm.

This one really gets me. Two IBM PC-330's. They are late LPX systems. Swapping components to get them working, and realize I can get them both working. Put them back together and one keeps resetting. Try swapping stuff about, think PSU? So end up recapping the PSU. Still a problem. Work out it is the case? Now these PSU's turn on with a latching (unlike ATX's momentary) switch. Turn's out the switch was intermittent! Thing was worn out I guess, It would latch, then somehow loose contact and regain contact again.

Funniest thing i found in a PC was in a malfunctioning CD-ROM drive that kept opening and closing. It was a small piece of paper that had written on it "Breaks CD-ROM drives. Ha Ha ha". Stupid, but Ingenious.

mR_Slug wrote on 2020-06-25, 20:24:

Funniest thing i found in a PC was in a malfunctioning CD-ROM drive that kept opening and closing. It was a small piece of paper that had written on it "Breaks CD-ROM drives. Ha Ha ha". Stupid, but Ingenious.

So someone put a piece of paper in the drive to force it to open/close and they thought it was funny ? Sounds like something a teenage kid might do when the parents threatened to take computer privileges away, just cannot fathom an adult doing that but we have some wacky adults out there from what the news shows lately....