No floppy after CPU Swap/ Dead MB

[Terry Lealos]

Have PM599LMR MB with AMI Bios String 52-0601-001437-00101111-071595-000000-001_V90_8670-H was working with a Cyrix 266. Went to install AMD K6-III 450 after flashing MB w/ 2k0930s. Computer confirmed install OK. Then upon recieving AMD CPU I was instructed to set Vcore voltage to 2.0. I went into setup and User Defined the voltage setting ONLY. Shutdown and swapped out my CPU's. Restarted to a blank screen, w/ no audio sounds. I shut down Cleared my CMOS and re-swapped back to my old Cyrix and got low battery select F1 for setup. I did and reset my CPU to Auto and shutdown. Tried to re-install my new AMD again and still a blank screen. Only this time clearing my CMOS had no effect and even my Cyrix boots to blank screen. I wanted to try Bootlock, but my floppy fails to light. My other devices flash, KB, CD's etc. But no floppy. I have tried another floppy and cable, also removing battery o'nite, shorting contacts on battery holder... I am at a loss. How can I get my floppy back? Terry

[Denniss]

A K6-3 needs at least 2.2V and early models need 2.4V .
Only the K6-3+ is rated for 2.0V or lower
Set your FSB spedd to the lowest possible before changing CPU
Make sure you set your CPU multiplier in Bios manually to 1.5 - maybe the Bios sets multiplier to 2x and your CPU thinks it's 6x

[Terry Lealos]

Thanks Denniss, but how do I get it to post with no floppy?

[KachiWachi]

Did you double-check your floppy connections?

Mine has the old-style large connector (looks like a short ISA slot) and sometimes I have to wiggle it a bit for it to make a good connection...

It seems strange that you were able to swap back to your old CPU once, but not a second time...

[Terry Lealos]

I tried a new floppy drive and new cables. Just can,t figure why I lost my floppy on POST, while it seems my cd's and keyboard are all lighting up. Is there any other way other than jumper or removing battery to Clear CMOS?

[Terry Lealos]

Do you guys think an external USB Floppy might work to install my Bootlock Floppy? Since my onboard is not posting? Let me know

[lucske74]

And if you load the defaults (F2 or Del, F5, F10)

[Ritchie]

Providing floppy was working OK before, bootblock may be corrupted beyond looking for floppy. As per your original post floppy was working OK until voltage change. Maybe you recieved on-screen messages telling you to make changes that fried your CPU, which we hope is not the case (bad case scenario).

Check your floppy connection - I know it is easy to misalign pins on floppy connections both at board and floppy end and also to reverse the cable.

I take it you cannot enter BIOS setup but if you use the clear CMOS jumper or remove the backup battery for long enough this should clear the settings, and with some luck restore to a default where the floppy is correctly configured. Possibly just your CPU setting is bad which may reset itself when the CMOS is cleared.

[ruelnov]

If I understood your post right, your system is indeed not booting up (no video, no beeps, no floppy access). So you cannot expect your floppy to come alive!

I also encountered this problem before, and I realized that Bootblock indeed executes but it finds the BIOS ROM checksum OK (i.e. passed). And so control is passed to system BIOS (original.bin for award v6 bios). But the system hangs just after system BIOS takes over due to inconsistencies in CMOS settings or DMI settings. And that is why the onboard video is not initialized, same with system speaker and floppy drive.

I fixed this problem of mine by forcing a checksum error, and so control is not passed to system BIOS anymore but this time Bootblock invokes the built-in bootblock recovery routine (i.e. initializing ISA/PCI VGA Card, system speaker, RAM, and floppy drive). And this enabled me to reflash my BIOS from Drive A, and hence recover my dead system.

If you're not successful in recovering your system by clearing CMOS, you can try Bootblock recovery if you're confident with it (see my post "Forcing Bootblock in..."). If you're not confident with Bootblock recovery, consider "hotflash", "replacement bios", or "reprogramming your bios with EEPROM programmer".

[Terry Lealos]

Ok you guys, Iam going to try the battery out o'rnite, if still no floppy I will try creating checksum error. Can someone tell me the address pin locations on my Syncmos F29C51002T-90FC chip? Thanks again for all your help!

[Terry Lealos]

OK you guys! I must be a huge dummy, cuz I have been to 2 different Syncmos website looking for the address schematic for the 32 pin chip in order to short while bootup and create a checksum error... Don't fail me now......someone get me the address pin ID's? Please? Thanks!!

[Ritchie]

Maybe someone else can help you with those PIN IDs, but if not:

1) Be prepared to risk further damage to your board.
2) Try the two pins at each corner of the chip first.
3) Try different pins and see if you get the correct ones.

Also,

* With a internal speaker connected, if you have CPU and RAM, and hear two tones (NOT the RAM or VGA codes), your BIOS is going to bootblock.
* With a floppy connected, if you see a light come on when you power on the system, it is attempting a bootblock boot.

Finally, maybe your current BIOS does not recognise your AMD CPU. Hopefully you did not overvolt the Cyrix when you proceeded as instructed to change the voltage for the AMD (as I understood you changed the voltage while running the Cyrix). If not, then clear the CMOS, install the Cyrix, and maybe the BIOS will default to correct settings to boot with the Cyrix when you next power on. If this is sucessful, then perhaps what is in order is a BIOS upgrade to ensure support for the AMD, and then try again. I would probably be using the auto setting for the voltage, if available, so as to avoid any incorrect voltage setting for either CPU.

[KachiWachi]

2k0930s does support the K6, so that isn't it.

I'm beginning to think that somehow the CPU's died. If you can check them in another motherboard, I would try that.

Also verify your CPU again for Vcore. You might have blown the VCore regulator, which would also render the Cyrix as apparently dead. I'm not sure what the 599's regulator is capable of supporting current-wise.

K6-III-450 @2.4V = 13.50A VCore
K6-III-450 @2.2V = 12.15A VCore
K6-III-P-450 @2.0V = 8.50A VCore
K6-III-(+)-450 @2.0V = 8.50A VCore

A great page I just came across to see various CPU Electrical Specifications - http://users.erols.com/chare/elec.htm

[ruelnov]

Why not simply remove all RAM modules, then power up. If you hear a long beep then your CPU is working.

[ruelnov]

Try shorting WE pin with A17 pin, with reference to the datasheet that can be found here:

http://www.syncmos.com.tw/products/down ... 51002T.pdf

But please read the detailed instructions as described in my post on "Forcing Bootblock...". And when bootblock activates, include a switch in your command line to save your ROM BIOS to the floppy so that you will have a backup file that you can count on.