Hi everyone,

I have this D630 (UMA) board that's giving me trouble. When i power it up, all it gives me is the LED blink code that's supposedly "RAM not detected".
https://www.parts-people.com/blog/2014/ ... ndicators/

I've replaced the southbridge with a known-good one, tried two different good CPU's, tried several RAM sticks, reflashed the BIOS, but still the same

I'd appreciate any ideas you might have...

Memory Min: 512MB DDR2 shared 667MHz;
Max: 4GB DDR2 shared 667MHz
For systems using Windows XP, up to 256MB of system memory may be allocated to support integrated graphics, depending on system memory size and other factors, while for systems using Windows Vista, up to 358MB of system memory may be allocated to support integrated graphics, depending on system memory size and other factors.
The total amount of available memory will be less than 4GB. The amount less depends on the actual system configuration.

https://www.dell.com/community/Laptops- ... -p/4566284

I'm not sure you've read or understood my initial post.

The board doesn't even POST / boot.

The CPU / NB / SB get warm, all the power rails seem to be ok, but i get the NumLock on and CapsLock & ScrollLock LEDs blinking, which (at least in theory) is a RAM detection problem.

I'm sorry, but are you doing this on purpose? Or is Google Translate messing up my previous posts so badly?

My point is, i already know that, and i'm afraid neither of your posts is helping The link i included in the first post says the same thing as your last link.

I'm sorry...
---------- Добавлено спустя 15 минут 7 секунд: ----------
Remove memory card's. Try power up without memory. Power down. Install one memory card. Power up. Look...

I've already done that too (read my first post a bit more carefully), but no change.

Khron, MEM_SDATA and MEM_SCLK, VDDSPD ok? 1.8V, 0.9, slots...

Why South? North!

Is not the same as remove all memory sticks and switch power on...

I replaced the southbridge, because the MEM_SDATA and MEM_SCLK go into the southbridge, so i figured if the (SPD) detection isn't ok, that's where the problem might be.

Now that i've re-checked the schematic, i see Q21 & Q27 are used as level-shifters in-between the SB and the DIMMs.

I measured some diode-drops (red probe on ground, black probe on each leg of the two mosfets) and one of them didn't read right.

I took them off, re-measured, and the source of Q21 (MEM_SDATA) showed as a near-short to ground.

A dab of flux on the 195-197-199 pins of each of the two DIMMs and some fresh solder, and that reading cleared (now showing 2.38v drop), which is more normal. The mosfets measure ok out of circuit.

Sadly, no change...

One odd detail - for 4-5 seconds after power-on MEM_SCL is about 0.3V, then goes high (3.3V), but no activity happens (analog oscilloscope).
Same with MEM_SDA, but that stays at 0.3V until it shuts down on its own (15-20sec), no activity here either.
Same behaviour with and without DIMMs inserted.



The point is, with any ram sticks i tried, it does the same thing as without any ram sticks (the "RAM not detected" LED error code).

Show a bit more carefully with magnified glass all surface of pcb. A dab of flux, damaged printed wires,cold solder, capacitors with big ESR etc...

Any particular area i should be looking at?




PS: I'm starting to consider replacing the NB now...

Chech what is the status of the memory connectors.
They or connected to it printed wires may be damaged