Socket 5 mainboard

[hbsoftware]

hi everyone
i am having a problem with a socket 5 mainboard ( the first gen pentiums with the fdiv bug)
i got the system at a junkyard, no cpu or ram, it is a compaq deskpro machine
fitted a cpu, populated the ram, it worked and i was trying to get it to boot from a hard drive, then it stopped working
no beeps, no image on the screen
tryed another cpu and lots of different ram sticks. the machine has onboard vga so i tried using an isa vga card...nothing

i have one of those post analyzer cards so i fitted it
all the leds for the different voltages are lit aswell as the frame, irdy and clk leds
the reset led is not lit
the card throws the following sequence of codes : 01 17 45 44 45 43 c1 96 then it stops
all the voltages test ok with the multimeter
no shorted tantalum caps anywhere
tried with and without cmos battery

i am at a loss honestly
its a very rare system and would love to get it to work
i am confortable soldering and i have an oscilloscope and dmm, do you guys have any idea of were should i begin testing??
i will post pics of the board later today

 

[Ruud]

AFAIK the codes are BIOS dependent. So find out what BIOS you have (sticker on EPROM?) and search on internet (or ask here) what the codes mean.

 

[rmay635703]

Does it stop when the hd is connected but work when disconnected?

Could be a reversed cable, a short or a weak PSU

 

[hbsoftware]

Does it stop when the hd is connected but work when disconnected?

Could be a reversed cable, a short or a weak PSU

HI
For eliminating any external sources of problems i am testing the bare board only and with a good known psu
it stopped working under any condition now

 

[hbsoftware]

AFAIK the codes are BIOS dependent. So find out what BIOS you have (sticker on EPROM?) and search on internet (or ask here) what the codes mean.

hi here is a picture of the board and in the second picture i believe the chip saying "Flash" is the bios but i cant tell what brand it is...
it appears to have sticker residue so i believe it had a sticker some time ago
the number on the chip is n28f010 but that tells nothing
searching online i found a thread from 2002 in another forum and someone stated the bios is AMIBIOS but not sure 100% if its reliable info

 

[GiGaBiTe]

The BIOS chip is a 128 kbyte Intel parallel flash chip.

N28F010-150 pdf, N28F010-150 Description, N28F010-150 Datasheet, N28F010-150 view ::: ALLDATASHEET :::

N28F010-150 Datasheet, N28F010-150 datasheets, N28F010-150 pdf, N28F010-150 integrated circuits : INTEL - 28F010 1024K (128K X 8) CMOS FLASH MEMORY ,alldatasheet, Datasheet, Datasheet search site for Electronic Components and Semiconductors, integrated circuits, diodes, triacs and other...

pdf1.alldatasheet.com

Those PLCC chips soldered to the board are a bit of a pain to remove, you need a hot air rework station and some flux. You'd also need an EEPROM programmer to read and write the chip, like a TL866II.

While the flash chip could have gotten corrupted, I doubt this is the issue. More likely there is a marginal component somewhere or a broken trace/VIA. That will be a complex and time consuming repair.