Tyan s2720 was working fine. cleaned fans and fiters then when I tried to boot up no bios and 7 beeps pause 7 beeps pause 7 beeps etc...

don't see that one in the list in manual
http://www.tyan.com/manuals/m_s5220_110.pdf

Replace the RAM and the sound card.

What motherboard do you have? If you don't know, provice make and model of your system and maybe we can find out that way. Is it one long beep? Are there any other beeps and/or a sequence. A good place to start and alot of times, depending on your bios, 1 to 3 beeps means a problem with the RAM(memory). If you have more than 1 stick, you can pull them out, restart and if the beep is the same, you've probably found your culprit. You can then insert one at a time in one of your slots, then restart. If this works, you've found a good stick. If not, try another slot and restart, etc. Try all sticks in all slots.

bio need fixed jim

Well, first off, make sure that it's plugged in. I'm guessing that you already did that, and already checked that the PSU's powerswitch was set to " on ".

If your PSU can run at more than one voltage, I would check to see which one it's set to. If you're from the United States, chances are that it should be set to " 115 ".

If the computer makes any beeping noises when you try to power it on, that could very well tell you exactly what the problem is if it's a dead piece on the inside. Just listen to the beeps and look online if you can find out what the beeping error code means.

I hope this helps!

The Tyan MP boards do not support legacy USB. You have to use a PS/2 keyboard to get into the bios. If possible, I would clear the cmos by popping the battery out or finding the jumper to clear it. Then try to access bios again from ps/2 keyboard.

These boards also have compatibility problems with many video cards. Check Tyan's website for a list of supported cards if you are not using onboard video.

As long as the heatsinks are properly mounted on the CPUs with thermal compound, the fans are operating normally, and air is flowing through the system, the chasis that you run these boards in shouldn't matter.

If all fails, try removing pci devices, external peripherals and drives one at a time to try to eliminate possible causes.

Video card reference: http://www.tyan.com/archive/support/html/video_s2466.html
MB Manual:
ftp://ftp.tyan.com/manuals/m_s2466_120.pdf

Dissemble your whole PC. Clean thoroughly. Check BIOS battery with a multimeter. Try to boot without expansion cards. Change RAM if you have extra one. There are so many procedure you can take. Keep informing.

try first with one cpu and only one stick of memory in socket zero

if the video does not come on... try next to reset the bios .. clear the settings... it may be setup to search for a pci or pci-e video card in the bios

next try to test the wattage being pulled into the system at boot... should be over 200watts.. may indicate a power issure

are there any beep codes ... post codes or ... is there a single beep tone during power on to verify the motherboard is functional and checks out fine at self start...

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1. If the MB has jumpers, you must make sure they match you CPU.
2. Make sure you have the right memory modules and that they are installed correctly.
3. Unplug all drive cables from the mother board (HD, CD, DVD, Etc) and then try to boot. If you see video, plug them back in one at a time.

Hope that helps...

Geno

It sounds like you?re an experienced hardware guy so I won?t bore you with the basics. When I?ve gotten stuck on a new motherboard no-booting problem these steps have helped me: -Make this as basic a machine as possible. You don?t need much of anything to get the POST to display and anything else just adds more variables. -double check the processor and memory, ensure they are correct for the board. Make sure the manual is the correct one for your board. -Try setting the BIOS to the manufacturers ?Safe? settings or default settings. You might even want to pull the backup battery out, unplug the power supply and let it set for 30 minutes to void the BIOS settings. -Verify the power supply is working correctly, preferably with a power supply tester. If you can?t then try putting this power supply in another computer to make sure it not only turns fans on but really supplies the correct voltage needed to make things work. -Buy or borrow a pre-boot test card. This is a diagnostic card that plugs into a PCI slot of your PC and will give you a much better diagnosis of what is going on. You can usually pick one up for about $35. - Make sure your CPU fan is plugged into the right motherboard connector, the newer boards will check for the CPU fan. I would suspect that if this were the case you would see something on the screen but you never know. Last but not least you might actually have a defective board. Granted it doesn?t happen too often but I?ve had two or three dead out of the box over the past few years. Chances are if you?ve gone thorough all of this and relate the steps to Tyan support they will send you a replacement. And if the new board does the same thing then you only have two remaining variables left; CPU and memory. Good luck and if you have any other questions please let us know.