Main Site Nav
Topics Topics Edit Profile Profile Help/Instructions Help    
Search Last 1|3|7 Days Search Search Tree View Tree View  

Need help with 486 and mobo/bios sett...

Trish's Escape from Hardware Hell Help Board » Setup and Configuration » All the Rest » Need help with 486 and mobo/bios settings « Previous Next »

Author Message
Posted on Tuesday, May 23, 2000 - 12:24 am:   

I have a 486 motherboard, (used, but new to me, I've never seen it fired up before). The board didn't come with a CPU, so I put an Intel Overdrive P24T (PDOVP5) on it and maxed out the ram to 64meg (all matching sticks & leads). I set what jumpers that I could figure out, put in a video card, my oldest harddrive (85MB, with Dos on it) that I know still works good, and hooked up a 3.5 floppy drive. When I turned it on, it does everything fine until it needs to boot something, then it just hangs. The Bios autodetected the drives fine. I think due to my inexperience, I probably don't have things set right, the jumpers that I didn't understand I just left alone and they might need to be changed because of the Overdrive processor. I made up a list of my motherboard specs, settings and bios settings and what I have them set to that you can find here "" I would be so grateful if someone that knows about settings and maybe this processor could take a look at this and give me some sugesstions about what I need to change.

Adam Emswiler (Abe)
Posted on Wednesday, May 24, 2000 - 6:14 am:   

Without knowning where it's hanging, it may be tough to troubleshoot this....

Everything appears to be correct as far as the jumpers go.

Here's what I would do to start:
Disconnect the IDE cables, and remove most of the memory (leave 4MB or so in). In other words, get the system down to bare minimum with just enough power to boot to a floppy disk (make sure you turn everything off in the BIOS that isn't needed - IDE primarily).

Try to boot to a diskette and see if this works.

If it still hangs, you may want to use Jumper J7 to perform a CMOS clear, and try the above steps again. If this still doesn't work, you want to see if there is a possible BIOS update.

If the system boots to the floppy drive, then start by adding just a single IDE device. And try the steps again.

If this doesn't help, let us know, and we can try to go further from here...

Danny Albers (Danny)
Posted on Wednesday, May 24, 2000 - 2:51 pm:   

Do you get Video when you boot?

How many beeps do you here from the speaker when you boot?

Does you floppy light turn on then off when you boot?

Does the bios screen disappear to be replaced by a DOS screen with a hardware chart? Or does it fail before that?

I would like to know how far through the boot process you are getting before you have trouble.

Usually when a computer gets to the point where it is ready to run the bootstrap loader (the thing that checks the sector 0 of a drive for a boot file), it will give some kind of message like OPERATING SYSTEM NOT FOUND, or, INVALID BOOT SECTOR, or something else. Are you getting any of these messages?
Posted on Wednesday, May 24, 2000 - 4:21 pm:   

I'm getting one beep. Yes I do get video, and color Energy Star logo at the boot. The floppy light does come on then off also I can hear it access the drive when it does the drive sequence check. It reads the bios screen, version & date, memory check and cpu are exactly what they should be. As soon as its done reading the memory the cursor jumps down a line and thats it, it just sets there blinking. I've left it set there like that for few minutes and nothing. I've been looking around the web and have seen some info on the the P24T (PODP5V 83Mhz) Overdrive Processor and how it handles internal Write-back or Write-through cache, something I don't know too much about, but am trying to figure out.I will try the steps Adam mentioned above and will check back.
Thanks for your help,
Danny Albers (Danny)
Posted on Thursday, May 25, 2000 - 7:53 am:   

Well, from what you have told me I can tell you that your motherboard is setup correctly.

Have you tried to boot from a floppy or are you trying to boot from the hard disk? The problem is probrably a disk problem of some kind.

I know your hard drive is setup correctly cause you get video, in 486 boards, if you have an IDE cable backwards, you will not usually get video.

I know your floppy is on correctly cause the light comes on and then off, if it was backwards, the light would just stay on.

I know that your board is jumpered at least 99% correct as you get 1 post beep indicating all is well with the mainboard.

I would try a different boot diskette, or see if maybe the hard drive you are trying to boot from was originally formatted on a system that used LBA mode, as your system may not support this mode. I have a good feeling it is a drive issue of some type.

You are probably wasting your time with the cache write-back/write-through cache idea, that is not a problem. If the CPU was setup incorrectly, you should get more than one POST beep.

Good luck.
Danny Albers (Danny)
Posted on Thursday, May 25, 2000 - 11:40 am:   

Something that did just come to me

I had worked on a system doing the same thing a while ago, the hard drive would detect fine but the cursor would just sit there, flashing, while the computer tried to access the boot sector.

It turned out that the IDE cable was on correctly, but not all the way on. You may just wanna check that out on your machine while your working at it.
Adam Emswiler (Abe)
Posted on Thursday, May 25, 2000 - 12:21 pm:   

I agree with Danny that this problem appears to be related to a boot problem, and not the actual jumper settings of the motherboard.

You may even want to try different cables for the drives if you still encounter problems.
Posted on Friday, May 26, 2000 - 3:04 am:   

I didn't have time to do anything with the 'ol beast today, had to work. But one thing I did do was look in the old case that I took the 3 1/2 drive out of. It was an old AST 386SX (it had alot of proprietary stuff I forgot about). I bought a new cable for that drive to go in this 486 because the old one was too short. When I looked in the old case and at the old cable I noticed some differences. The old cable had the old style 5 1/2 (twisted) connector at one end, the middle 34 pin connector is where it plugged to the motherboard and the other end of the cable went to the 3 1/2 34 pin. I noticed on the old cable that there was a stop-pin 3 pins down from the red side, so that pin is missing on the floppy drive and I didn't notice it when I plugged the new cable in. Im not sure if that is a common feature or was that an AST OEM proprietary thing? This drive is an Epson SMD-300 and the only thing I can come up with is a txt version of the jumper settings, but no pinout specs. Other brand floppy pinout specs I looked at seemed to have all the pins. I'm wondering if that might be causing a problem with the floppy not booting. As far as the hard drive, this evening I read a post where this person couldn't get his Western Digital to boot so he just took all of the jumpers off and then it booted fine, so I will try that in the morning. And for that IDE cable, I've checked it about 20 times, the only way it would be on there any tighter is if I super glued it :)
Danny Albers
Posted on Friday, May 26, 2000 - 6:58 am:   

It would make sense.

Many times when you try to install a proprietary floppy or floppy cable in a clone system, the computer will pass the POST test for floppy seek, but will hang when you go to access the floppy drive, as when it searches there for a boot disk.

Try changing your boot sequence to C: A: and removing the floppy cable, and setting the BIOS to no floppy installed. If you can then boot from your hard drive, you will probrably need to use a different Floppy drive.
Posted on Saturday, May 27, 2000 - 2:35 pm:   

I changed the settings and removed the floppy drive and had it try to boot from the C: and it's doing the exact same thing with this drive. Also tried a new IDE cable. It acts like it wants to access the drive, but then just the blinking cursor. From what I am running across in some of the posts on forums and newsgroups, is that Intel jumped the gun with this Overdrive CPU and announced it to the motherboard manufactures way before their final production, but changed stuff in the chip after they announced it but before it was released. And the motherboard manufactures, it seems jumped the gun too, because they made their boards to use that chip before Intel released it. What has me confused is that FIC, who made this motherboard, has jumper settings in the manual for the P24T and also a P24T Cache Burst setting in the bios Chip Setup. But when I went looking around in their FAQ pages, this board isn't on their list of boards being able to use that chip. I emailed their support to see if it is compatable or not, hopefully they will respond. In the meantime, any other ideas?
Danny Albers (Danny)
Posted on Monday, May 29, 2000 - 6:55 am:   

I all can say is that generally, if a board doesn't support a chip, it will not work at all, or it will display the improper chip name/settings on the boot chart when you boot.

It should not be giving you ONE post beep indicating all is fine like you have been getting.

One thing I have learned, is that there are exceptions to everything and it may well turn out to be the chip. If you want to find out for sure, borrow and standard 486 off of someone, one that you know works, and try that chip out in the board, changing the jumper settings to match it.

If you get the same problem, its not the chip. If you don't, it is the chip.

At least you can stop wondering then.

There is also the possibility that the mainboard doesn't work right. The IDE controllers or FDD controller could be bad. You did say in your first POST that you had not seen this board fired up before.

Good luck.
eddie l
Posted on Saturday, June 24, 2000 - 12:35 pm:   

hi judy
i know how frustrating that is but keep at it as i usually do and you will get there. it occurs to me that if you try to boot with a fat32 disk a fat16 system will not read the disk. if you have only one floppy it needs to be on the furthest end of the cable also some older systems default to 1.2 meg drives you can check your bios at startup to see what format the floppy is set. check the drive select jumpers on the floppy usally set to ds1. finally if you have dos6 boot up with this. if its not the original it may be on a fat32 disk. if it detects the hard drive and it is not formatted correctly it will format it so make sure there is no info on the drive you cant live without.
good luck (to both of us as this is my first ever posting).
Jason Lockhart
Posted on Friday, June 30, 2000 - 11:01 pm:   

From what she had said, I would assume that the disk is not formatted FAT 32 as it is only 85 MB and has nothing but DOS on it.

Add Your Message Here
Username: Posting Information:
This is a public posting area. Enter your username and password if you have an account. Otherwise, enter your full name as your username and leave the password blank. Your e-mail address is optional.
Options: Enable HTML code in message
Automatically activate URLs in message

Administration Administration Log Out Log Out   Previous Page Previous Page Next Page Next Page