DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R449

[inflex]

Have a DELL PineValley DIB75R mainboard with i3 on it. Something ruined R449 near the CMOS battery.

Schem/Boardview would be nice, else just the value of R449.

The DPAK is an adjustable 3A reg, R450 is between ADJ->VOUT, and R449 (dead) is ADJ->GND. If I can work out the required output voltage I can just make my own resistor pair up (or remove R450, measure it and then work out what I need for R449.

[inflex]

Re: DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R44

I thought it might have been a 3V3 supply reg, but checking on pin-3 (VIN) it's already only 3.3V on there, so it has to be something closer to 1.8V output most likely (unlikely to be 3.0V because the dropout of the 1085D is 1.3V), which is a bit concerning as I'm seeing 2.4V output, so the CPU could be toast

[piernov]

Re: DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R44

Did you find what is feeded by this regulator ? Might help you confirm the voltage of this line.

[inflex]

Re: DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R44

I think I'm going to have to pull the CPU out, find which pins are connected to the VOUT, and then refer to the 1155 socket pinout to see what voltage I should be expecting, or test on another 1155 MB (not sure I have another one though at the moment)

[inflex]

Re: DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R44

Using the continuity meter, I've found it's connected to (at least) pin AK11, seems to be VCCPLL

[inflex]

Re: DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R44

Looks like it should be 1.8V (even though that isn't the right schematic it is another 1155 board so I would assume that VCCPLL is going to be similar, and 1.8V does fit my idea that it can't be more than 2.2V due to the LDO's cutoff limit.

Worried though it's probably blown the CPU as I measured about 2.5V going through before, guess we'll see. I also have to now work out the resistor value, though that shouldn't be too bad, worst case scenario I can make up my own divider pair with the large stock of parts I have on hand from prior manufacturing.

[inflex]

Re: DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R44

The repair worked, but unfortunately after about 5~15 minutes the machine still reboots, even when just running something like MEMTEST86.

Ah well, you win some, you lose some.

By the looks of it, it was caused by a bug with caustic poop/pee/juice, as I found a couple of other places where there's been drops of crusty stuff.

[inflex]

Re: DELL Vostro 270s Pinevalley DIB75R schematic / boardview required or value of R44

I've uploaded a video of the whole process - and, as a further (final?) update, it turns out the PSU has its own issues after all, possibly badcaps, so right in line for this forum

Enjoy

https://www.youtube.com/watch?v=7Fge0AmZUgw