No POST, no beeps, no video

[sauton]

Installing additional RAM to a Cyrix 133 (unbranded make) has caused some unusual results. Mobo has four EDO slots which each contained a module with 8MB on. I was installing two new modules with 32MB on each. The slots are Bank 0 (slots 1 and 2) and Bank 1 (slots 3 and 4).

Initially, I installed the two new modules in slots 3 and 4. When I started it up, it counted 48MB and successfullly loaded Win95. Win95 also reported 48MB.

Problem being - 32 + 32 + 8 + 8 = 80MB.

So I thought I'd swap the 32MB modules into Bank 0 and the 8MB modules into Bank 1.

Having done so, the system refuses to boot. No POST, no beeps, no video. I've checked that everythings seated properly. I've removed the backup battery. I stripped the system done to the bare essentials (mobo, PSU, VGA card, CPU) and still got nothing. The VGA card checks out OK in another box.

Any guidance gratefully received.

[Ezzee Money]

Sounds like to me one of the two 32 sticks of memory is bad. You may want to try installing one stick at a time see if it works if it does pull it and install the other and see if it works. Also if they both work you need to check the Motherboard specs to see if it supports 80megs of ram.
Ezzee

[sauton]

Thanks for this. I should have said, I'm currently trying to start it with the original 32MB (4 x 8MB) installed.

[Bovon]

Some boards require that ram modules be installed in certain slots according to the module mb size. This is USUALLY the larger modules in bank 0 and bank 1, ect. But, sence your machine worked with the modules installed in reverse of that, but did not count the ram up to its max mb sounds like 1) a bios issue or 2) the ram modules may be double density modules that may not work in older boards. If the new modules are EDO, then the problem probably is a bios issue. If the modules are maybe PC 100, they probably will not work in a board designed for EDO.

Ram is backwards compatable, but the mainboard chipsets on some boards will not recognize the later, high density ram. Also, you are aware that old EDO DIMMs were probably 5 volt modules, and the more recent DIMM modules are 3.3 volt.

[sauton]

Thanks, that's very interesting - the new modules are definitely EDO. Would the modules have worked at all if the voltage was wrong?

If the BIOS is faulty, can it be replaced? I seem to recall seeing somewhere that they can be extracted from the mobo - does this require a special tool as it seems fairly secure in its socket?

Thanks again.

[Bovon]

A BIOS ROM chip contains software, simular in some respects to other applications you would use under Windows. The BIOS software can be reflashed to a newer version. Reflashing means to reload to another version, and overwriting what is there now...or, deleting the old BIOS software and re writing with a newer version. The proper term would be re programming.

But, yes a ROM chip can be removed and replaced if necessary, unless the chip is soldered into the motherboard...rare anymore to find one of these. A special tool is generally required, but can be done otherwise if VERY carefull.

As long as you bought EDO DIMMs for the new ram modules, the problem could be that you have added more ram than the BIOS will recognize. You need to check the manual for your board and/or write to the board manufacturer help tech's.

[frank5]

Try clearing the cmos. Does your board have a clear cmos jumper?

[TweakerXP]

No BEEPS at all means a dead mobo doesn't it????:confused:

[frank5]

No beeps could mean any of the above including bad mb.
Could also mean the the power supply plugs are not seated properly in mb. Check this.
Bad BIOS chip can cause this situation and so can faulty memory and fsb settings in bios. Some of the old mobos won't automatically reset bad bios settings upon reboot and the computer will respond this way until you clear the CMOS
manually .

[sauton]

Thanks for the last few messages.

The PSU plugs are properly seated into the mobo.

Old BIOS chip (AMIBIOS 586 1985-95 American Megatrends) has now been extracted and replaced with an Award Software Inc 1995 PCI/PNP 586 chip. The machine now beeps (and beeps and beeps) when it is booted but still no video. Doesn't beep when only bank 0 (RAM slots 1 and 2) is occupied.

In order to clear the BIOS using jumpers, I understand that there's a specific jumper setting but do I just remove the jumper and put it back or do I need to boot the PC whilst its removed (sorry to be dense).

Thanks again.

[frank5]

To clear bios, pull power cord, set jumper to clear cmos mode. I then put cord in and push in power button. You will get no response. Unplug power cord, reset jumper to normal mode, powerup system an your bios will be cleared.
You should replace your old bios rom chip and try clearing the bios to see if the old chip is funtional. When fixing computers, only change one variable at a time. This is true in any science.