Denniske1976
Experienced Member
Hi guys... well, after a week of loosing tape after tape and also 3 tape drives (QIC80 with all my old data, tapes didn't even survive a retension and I had about 50 tapes). Now also my 486 seems to have passed :-(
The motherboard (or is it mainboard?) looks totally OK, I can't see anything that even looks to have cracked or burnt at all. What happened is that I acually was able to power it up (it's been standing in the loft for about 3 years now), it booted normally... then just powered off. And since then when I try turning it on, the PSU does it's thing about 1 second, LED display comes up (you know, the cool 66MHz LED) and then it immediately shuts down again. No beeps no nothing. So the mainboard shorts the PSU I guess. Tried another PSU and same problem.
I'd really like to try and fix the board, since it's been with me for the last 30 years or so and it's a very nice board: 3x VLB, 8x 30pin SIMM, OPTi 495SLC chipset and 256K cache, oh and there's no battery corrosion since that I took that out a long time ago and replaced it with a CR2032 on the external battery connector. What would be the correct approach as to try and repair this? (I had this happen to 550/5160 motherboards before and you just cut the C56 or whatever blew up and all was cool). I do have a multimeter, so my guess is start with a PSU attached and see what the pins of P8 and P9 read?
Next weird thing: being a hoarder of some kind, I found another 486 motherboard so I put that in the case (the original board is looking pretty in my display stand now). Also an OPTi board (just not as nice as the other one). So all seemed to be allright with the world again. I installed the board, replaced the CPU (Intel 486DX2-66), 4 sticks of 30pin 4MB SIMM in it, Gravis UltraSound MAX back in place, disk controller (VLB) back in place and connected to my NEC 4speed CD-ROM and Quantum Maverick 540MB harddisk, 1.44MB floppy. Put the Diamond Stealth 32 back in place (2MB VLB). Powered on and all seemed OK except that there was a low battery message on screen and I had to run SETUP (because I just connected a new CR2032 to the external battery connector). So I went into SETUP, set the date and time, A-drive floppy and autodetect the harddisk (and that found the right settings for my harddisk too). EXIT and SAVE, reboot and all seemed OK. EXCEPT: I can't get it to read floppy drives (and that's weird as with the other board yesterday I was able to boot from a DOS 6.21 floppy and use other floppies, and all of a sudden now it won't read that DOS floppy nor any other and when I try to format a new one all I get is error reading disk ABORT/FAIL/CANCEL or whatever). The other weird thing (I guess not related) is that I set the date correctly and when I reboot is back to the same month/day but ALWAYS 2094... dafuque is up with that? So when I disconnect the battery, it resets to 01-01-1989 I believe and that's normal behaviour. Then I set the date in SETUP for 02-08-2021, I exit (and save of course) SETUP, system reboots, all is fine: 16000KB memory counts, P24D-S at 66MHz (for some reason it won't list the CPU as 486DX2, even the jumpers are set for it but in the manual jumpers for 486DX2/DX4 and P24D are the same)... I end up in DOS and when I type in the DATE command it comes up with "Current date: 02-08-2094" and when I CTRL+ALT+DEL and go back into BIOS SETUP the date is also 02-08-2094. Every time again after I cange it back to 2021 it's going back to 2094 (and not 01-01-2094 or something, no the month/day I set but just in 2094).
So now it seems I'm without a working 486 :-D :-( But anyways, if any of you guys would have some tips on that defective motherboard? It kinda looks like brand new and like I said: it was my first VLB 486 board and always worked great. I can't imagine this would be dead now. So any help would be greatly appreciated :bigups:
The motherboard (or is it mainboard?) looks totally OK, I can't see anything that even looks to have cracked or burnt at all. What happened is that I acually was able to power it up (it's been standing in the loft for about 3 years now), it booted normally... then just powered off. And since then when I try turning it on, the PSU does it's thing about 1 second, LED display comes up (you know, the cool 66MHz LED) and then it immediately shuts down again. No beeps no nothing. So the mainboard shorts the PSU I guess. Tried another PSU and same problem.
I'd really like to try and fix the board, since it's been with me for the last 30 years or so and it's a very nice board: 3x VLB, 8x 30pin SIMM, OPTi 495SLC chipset and 256K cache, oh and there's no battery corrosion since that I took that out a long time ago and replaced it with a CR2032 on the external battery connector. What would be the correct approach as to try and repair this? (I had this happen to 550/5160 motherboards before and you just cut the C56 or whatever blew up and all was cool). I do have a multimeter, so my guess is start with a PSU attached and see what the pins of P8 and P9 read?
Next weird thing: being a hoarder of some kind, I found another 486 motherboard so I put that in the case (the original board is looking pretty in my display stand now). Also an OPTi board (just not as nice as the other one). So all seemed to be allright with the world again. I installed the board, replaced the CPU (Intel 486DX2-66), 4 sticks of 30pin 4MB SIMM in it, Gravis UltraSound MAX back in place, disk controller (VLB) back in place and connected to my NEC 4speed CD-ROM and Quantum Maverick 540MB harddisk, 1.44MB floppy. Put the Diamond Stealth 32 back in place (2MB VLB). Powered on and all seemed OK except that there was a low battery message on screen and I had to run SETUP (because I just connected a new CR2032 to the external battery connector). So I went into SETUP, set the date and time, A-drive floppy and autodetect the harddisk (and that found the right settings for my harddisk too). EXIT and SAVE, reboot and all seemed OK. EXCEPT: I can't get it to read floppy drives (and that's weird as with the other board yesterday I was able to boot from a DOS 6.21 floppy and use other floppies, and all of a sudden now it won't read that DOS floppy nor any other and when I try to format a new one all I get is error reading disk ABORT/FAIL/CANCEL or whatever). The other weird thing (I guess not related) is that I set the date correctly and when I reboot is back to the same month/day but ALWAYS 2094... dafuque is up with that? So when I disconnect the battery, it resets to 01-01-1989 I believe and that's normal behaviour. Then I set the date in SETUP for 02-08-2021, I exit (and save of course) SETUP, system reboots, all is fine: 16000KB memory counts, P24D-S at 66MHz (for some reason it won't list the CPU as 486DX2, even the jumpers are set for it but in the manual jumpers for 486DX2/DX4 and P24D are the same)... I end up in DOS and when I type in the DATE command it comes up with "Current date: 02-08-2094" and when I CTRL+ALT+DEL and go back into BIOS SETUP the date is also 02-08-2094. Every time again after I cange it back to 2021 it's going back to 2094 (and not 01-01-2094 or something, no the month/day I set but just in 2094).
So now it seems I'm without a working 486 :-D :-( But anyways, if any of you guys would have some tips on that defective motherboard? It kinda looks like brand new and like I said: it was my first VLB 486 board and always worked great. I can't imagine this would be dead now. So any help would be greatly appreciated :bigups:
