A POST card would come handy. Have you tried to move the RAM from slots to slots ? Also did you try other sticks (are you sure it's truely FPM and not EDO since they look exactly the same)

Deksor wrote:

A POST card would come handy. Have you tried to move the RAM from slots to slots ? Also did you try other sticks (are you sure it's truely FPM and not EDO since they look exactly the same)

Thank you for the response. Yes I'm sure it's FPM as it works with other boards that don't support EDO. I've just ordered a POST card from Amazon, should arrive tomorrow.

I'd quadruple check the CPU jumpers and cache jumpers.
Any chance you can try a different CPU?

tpowell.ca wrote:

I'd quadruple check the CPU jumpers and cache jumpers.
Any chance you can try a different CPU?

Tried two other CPUs - no dice 🙁 Some questions..

1. What jumper settings should I use for no cache?

2. Does this board require an RTC to boot? The socket is just empty right now.

3. What BIOS is recommended for v3.1? At the moment I have the last official one flashed.

The POST card arrived this morning, but just shows ————

Is the BIOS chip inserted the right way (notch on the socket meets the notch on the chip)? Could be a bad trace somewhere or the RTC Dallas needs to be replaced/scraped a bit to add a CR2032 battery holder on top.

bjwil1991 wrote:

Is the BIOS chip inserted the right way (notch on the socket meets the notch on the chip)? Could be a bad trace somewhere or the RTC Dallas needs to be replaced/scraped a bit to add a CR2032 battery holder on top.

Yes, I have it inserted the correct way. Double checked.

airs wrote:

2. Does this board require an RTC to boot? The socket is just empty right now.

Most certainly. I've never encountered a board that would boot without the RTC.

quicknick wrote:

airs wrote:

2. Does this board require an RTC to boot? The socket is just empty right now.

Most certainly. I've never encountered a board that would boot without the RTC.

Thank you - I've just ordered a DS12887A+ from DigiKey.

You already have RTC (odin), you are missing a bios IC. Source one.

Cheers,

pentiumspeed wrote:

You already have RTC (odin), you are missing a bios IC. Source one.

Cheers,

Oh, no - I took the bios chip out before those pics.

One voltage seems low according to the status LEDs. Maybe you can investigate on that ?

that pin next to CB17 on the chipset on top of the empty cache slots looks a bit funny, is it bent, bridged or just a angle of picture?

treeman wrote:

that pin next to CB17 on the chipset on top of the empty cache slots looks a bit funny, is it bent, bridged or just a angle of picture?

Yeah, I think there are bent legs and a short on the UM8886BF chip and the UM8881F chip. Try using a thin blade to carefully bend them apart and hope there is no break.

Cyrix200+ wrote:

Yeah, I think there are bent legs and a short on the UM8886BF chip and the UM8881F chip. Try using a thin blade to carefully ben […]
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treeman wrote:

that pin next to CB17 on the chipset on top of the empty cache slots looks a bit funny, is it bent, bridged or just a angle of picture?

Yeah, I think there are bent legs and a short on the UM8886BF chip and the UM8881F chip. Try using a thin blade to carefully bend them apart and hope there is no break.

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Thanks for pointing those out! I've fixed the two bridges but unfortunately no change in the board's behavior. The new Dallas RTC should arrive tomorrow - hopefully that does the trick.

Does anyone know which BIOS I should be using for this version of the board?

Since u had some bridges go over the whole board looking for inconsistencies like this, there maybe more.

It would be nice to locate a pinout for the chips that were bridged see what pins were touching, hopefuly not your vcc in bridged and shorted a chip

a burnt chipset would def prevent the boot.

A quick way to see if your chipsets are shorted is power it on and keep touching both chips if one or both get excessively hot this is a bad sign.

apart from that you could check some or the pins with a multimeter on the chipset if they don't get hot and show bo obvious signs.

I have 2 of these boards, my one does boot with a low charge rtc however it won't boot with no rtc/dead rtc fingers crossed when u get new rtc it will live

Well the new RTC arrived - no change in behavior 🙁

Used my multimeter to check that the socket is getting 3.45v and it is.

Also - another, working 8433UUD arrived. I swapped the CPU, BIOS, and memory from it to the non working board and duplicated the jumper settings - no change. About to give up on this board. Only thing I’m unsure about is the cache jumpers - what should they be set to if I have no cache installed? Or does it not matter?

cache matters, it won't boot misconfigured, you need to consult the manual for this. I always could not find the configuration for no cache chips. Can you move the chips from the other board temporarily over just to test?

Apart from this first we eliminate what works, bios we can move/test on the other board, rtc is new.
cpu ram video card work too.

From here Power delivery is next, psu works/tested I assume.

Next is measuring voltages on the power plug. After voltages check out check continuity on the power lines, start at the power plug and trace them as far back and use voltmeter on continuity mode to confirm they all are connected.

Check violate on isa, pci slots (find pinout on Google check for the main voltages)

Next check cpu socket, turn on the board for a few minutes see if the cpu is getting warm means getting power. You can also boot with no cpu and check power pins under the socket for correct voltages (google for socket pinout)

I think cache is a good thing to start with here because it won't boot if no chips but configured for cache or tag chip is not there

If the board has a setting in the BIOS to disable the external cache then the board will normally boot with the external cache disabled. The external cache will be enabled after POST if it is enabled in the BIOS. Remove the tag ram from the working board and see if it will POST.

If the CPU is getting warm then it is probably getting a clock signal.

If you remove the RAM from the board and you are not getting any beeps you might want to check the data/address lines from the CPU to the UM8881F for continuity and possibly the data lines from the UM8881F to the BIOS ROM. There's probably no datasheet available for the UM8881F so you will have to work out which pins are what. If you can't get your probes into the CPU socket you can measure from the RAM sockets. I fixed a board recently where even though all the data lines looked good (UM8498F), one pin (D27) had separated from the board. It took me about 4 days to find the fault.

If you had a logic analyzer you could populate the external cache and monitor the data lines, checking reads against a copy of the BIOS ROM.