Member Avatar for dan826

Hello,

Firstly the machine in question is a Defcon(never heard of it either) ATX

It consists of:-
PSU model ATX-350
MOBO model L7VMM3 ver 1.0c
CPU model Pro3100A+ (soldered on athlon xp 2000+)
RAM model Spectek 256MB pc2700DDR (only the one)
CD R/RW drive model GCE8525B
Floppy Samsung model SFD-321B
HD Barracuda 80GB
Monitor Benq model FP557s
KB logitech model Y-ST39
Mouse Logitech
SW XP Home Edition


Switch machine ON, CPU fan works and LEDs on front panel light up, but nothing else happens. No bios beep or beeps, no indication or noise that either the floppy (when disc inserted) or HD are working, no video output or LEDs on keyboard. But CD drive's LED does come on and tray powers in and out.

Having read this forum and others, I have tried resetting the CMOS, reseating what few cables and equipment there are and then disconnecting all peripherals and starting the machine, the reuslts are always the same as above.

Any help will be greatly appreciated.

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  • Latest Post Latest Post by danteft

Dani AI

Generated

Short diagnostic guide for systems that power up (fans/LEDs) but produce no POST, no video and no keyboard activity. The checklist below complements the thread and focuses on simple, repeatable steps that isolate whether the fault is in power, memory, firmware/beep reporting, or the motherboard/CPU.

  • Bench the board: disconnect all drives, cards and nonessential peripherals. Leave motherboard, CPU+heatsink, one RAM stick, PSU, a case speaker and the video output. Power and listen for any beep pattern.
  • Speaker and POST codes: confirm a case speaker is attached to the speaker header. If none is present or nothing is heard, use a POST/debug card or a known-good speaker to capture error signals. Beep meanings vary by BIOS; consult the manual for exact codes.
  • Memory checks: test a single module in every slot and try a known-good stick if available. Intermittent or bad RAM, or a bad DIMM slot, is a very common cause of no-boot/no-video.
  • Power checks: verify main ATX and CPU power connectors are fully seated. Either swap in a known-good PSU or measure 12V/5V/3.3V rails with a meter under load.
  • Visual inspection: look for bulging or leaking capacitors, burn marks, loose CPU socket pins or improperly seated heatsink/retention hardware.
  • CMOS and front-panel wiring: clear CMOS per the manual and confirm front-panel connectors (power, reset, speaker) are correctly seated.

Advanced/precaution notes: use a POST card, swap parts one at a time and work on an insulated surface with the PSU unplugged when changing hardware. Keep a spare case speaker and a single known-good RAM stick in a basic repair kit to speed diagnosis.

Thread notes: later reported the problem was resolved and suggested a possible CPU failure as one diagnostic avenue. The above checklist helps narrow faults without assuming a specific component.

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Member Avatar for dan826

I've sorted it!

Member Avatar for goldeagle2005

what was the problem?

Member Avatar for dan826

The cable to the internal speaker was damaged, once repaired the bios was giving my three beeps, bad memory, replaced memory pc now ok.

Thanks for the interest

Member Avatar for danteft

CPU might be burned.

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