Please help with non booting motherboard!!

[HOTRODk62]

Ok here's the deal, I purchased a new, pci 486 mainboard off ebay, and I can't get it to boot up. I know my power supply and video cards, etc that I"ve tried with it are good, as well as the ram I tried. I tried it with the floppy and hd connectors, without them, with cache module in, and without it in, and even tried two chips, one of which I know works a dx2 66, and the one I didn't know about was a dx4 100. If I have the floppy connector ribbon on backwards, it lights up both floppies like it should when there is a controller error, and the cpu even gets warm, but I hear no beeps, and nothing gets to the screen. Anyone with any ideas about how to get this sucker to boot please tell me. I mean such as do you have to have 4 memory chips in the board at once, which video card type should I use, ISA or PCI?? and any other tips or tricks, I can't believe the board would be bad right out of the box. Thanks in advance..

[magk9]

Start with video only, with memory and keyboard, and make sure the jumper is not set to "drain" the cmos. Jumpers are set correctly for voltage, clock speed,& bus speed? Also, most 486's won't accept EDO memory...are you using Fast Page? That's all I can think of for now. Good luck!

[Ed_S]

You asked about using 4 simms, if this is 30 pin simms, yes you do need 4 per memory bank. If 72 pin simms, 2 per bank. Either way, be sure to put it in starting with mem. slot 0
About the video, if you've got an ISA card, try it for now & go to the PCI after finding this problem.

Double check your jumpers, it's easy to mess up with 2 processors being tried!

[CMonster]

with a 486 I think you need only one 32bit SIMM (72pin); but yes on the 4x8bit (30pin) SIMM / and it it true that most 486 boards will not take EDO DRAM, but it may if it is one of the newer 486 boards with PCI slots.

I know you are not that much a greenhorn HotRod, so it must be the board - maybe it is time to think of an RMA...

[This message has been edited by CMonster (edited 07-05-99).]

[Ed_S]

CMonster's right. Sorry, it's been a while.
Thanks, CM http://www.sysopt.com/forum/smile.gif

[HOTRODk62]

Thanks for the help guys, I haven't had time to try anything else with it, been a hectic weekend, no it's not my first system to build or anything, just that I didn't know if the board being a 486 made things different. I had the cpu jumpers right although there were a huge array of them to set, now that is if the sheet I had was correct on the jumpers, only reason I tried the second cpu was because the first one I was using was given to me and I wasn't sure about it, I would think the memory would take edo, and in pairs, since it does have 3 pci slots, and has onboard ide, and floppy controllers, and is a green pci board, that's supposedly new, I bought this board off ebay, mainly because it was a steal, hehe maybe now I see why, I"m going to send the guy an email about it, and see what happens, and I'll let you all know how it went..Thanks

[KillerBug]

Ya, I have recieved a mobo off of ebay that died, just a junk 440LX, but still a mobo.

[HOTRODk62]

Ok...I figured it out...well er sorta, you see the cmos jumper WAS set to clear, so when I fixed that it booted up, I can't imagine someone shipping a board like that, and it was with the internal / external clock jumper, so I missed it, but here is the thing I"m having now, it has a AMI bios on it, and I"ve tried 3 diff video cards, 2 tridents isas 8900s and some sort of huge eisa bus card that takes up the bottom slot isa and an extended slot, all the video cards get a picture to the monitor, but it always says cmos video type mismatch, and it's set the ega/vga, and no other mono settings change the message, and it even hangs in the bios, or won't go to the bios sometimes, I know these aren't great cards but heck they're vga, and even 1 mb and it's a 486 board, so why won't they work??? I've searched for a setting such as on my newer motherboard like init display first or something, but there is none I can find, please help if anyone knows how to fix this, and I"ll be set... http://www.sysopt.com/forum/wink.gif thanks again

[CMonster]

I have no info on the video mismatch but I am curious to know what happens.

Just a quick over simplification about memory and the 486: from what I've read - and only going by my sources here, I understand that the 486 (and 386) have a 32bit wide path to memory (4bytes at a time)or some such thing like that, and since the old 30pin SIMMs were 8bit you had to use 4 of them (i.e. 4x8=32), and since the newer 72pin SIMMs were 32bit it required only one to be installed...but of course you could install more.

THEN with the advent of the PENTIUM (a doubled-up 486...yep, dual 486s -hey I just read this) this increased the path to memory to 64bits wide (8bytes at a time) and it required that 32bit SIMMs be installed in pairs. Twice the bandwidth to memory, that is one of the reasons the Pentium was so much faster than the 486 even at the same clock speed.

[BBA]

Actually, there should be a bios setting or jumper setting to specify CGA/VGA/SVGA types, since it is capable of multiple types, hell prob even VESA Local Bus too!

BBA

[HOTRODk62]

yeah theres a setting for video, that's what I don't understand, it's set on EGA/VGA..hell that nearly covers them all...only other options are like cga, and mono, a couple other really meager ones, but it was set on ega/vga from the start, so I cant see where the mismatch occurs, that's why I thought it might be some other video setting it was referring too, that one seemed too obvious...but I'm still gonna try a pci card and see what it does with that...hehhe