currently have 3 dead/damaged rex here. 

#1 - dead vcore fujitsu + some conductive thermal paste near NB shorting the nb vrm. Board appears to be working fine again. 

#2 - dead vcore fujitsu, vcore shorted to 12V. Found dead mosfet, replaced it + driver + controller, it blew straight up again. with lab psu it goes beyond memory training during post, so I assume with proper epower it should work properly. 

#3 - dead vcore fujitsu, vcore not turning on. lots of corrosion. With controller removed + epower it doesn’t attempt going beyond 00. other unnecessary chips have been removed. tried powering SB with lab psu to check current draw, it only draws 15mA at 1.05V which seems very little. Suspicion is dead SB but beyond that no idea. 

 

resistances appear normal on all 3 boards after faulty parts have been removed/fixed. 

 

Board #2  

Edited July 18, 20204 yr by ground1556

Here's another puzzle.

Was benching E8500 with RE on cold. Got a shutdown with no load, board did not react to anything anymore. Dried it up, turned it on next day - CPU Fujitsu exploded. Removed the Fujitsu and now board does this:
without CPU: https://www.youtube.com/watch?v=JPjkpKS5dUU
with CPU: https://www.youtube.com/watch?v=vQFnkCpdekc
In both cases it powers on itself as soon as it gets power from PSU. The LED shows PLL voltage.

CPU, PLL, VTT, NB and SB resistances are within 10% of working boards.

Any ideas what it could be?

 

Edited July 24, 20204 yr by TaPaKaH

On 7/24/2020 at 12:58 AM, TaPaKaH said:

Here's another puzzle.

Was benching E8500 with RE on cold. Got a shutdown with no load, board did not react to anything anymore. Dried it up, turned it on next day - CPU Fujitsu exploded. Removed the Fujitsu and now board does this:
without CPU: https://www.youtube.com/watch?v=JPjkpKS5dUU
with CPU: https://www.youtube.com/watch?v=vQFnkCpdekc
In both cases it powers on itself as soon as it gets power from PSU. The LED shows PLL voltage.

CPU, PLL, VTT, NB and SB resistances are within 10% of working boards.

Any ideas what it could be?

 

have a similar board now. vcore vrm is dead, 12v vcore now and does exactly the same as in your videos... also the already replaced fujitsu exploded again these boards are a nightmare

Edited October 13, 20204 yr by Gigelz

1 hour ago, 4n0nym0u5b3nch3r said:

Damn shame there is no boardview available for the REX.

 

Some ideas can still be sourced from P5Q3 Deluxe boardview. Though quite different (chipset, layout and missing rog chips), they utilise same concept. 

10 hours ago, 4n0nym0u5b3nch3r said:

Damn shame there is no boardview available for the REX.

 

I have boardview for REX, but i can't share it with you.

Just PM me and I can help everyone with repair 

i think its time to revive this thread atleast a little bit. after we found and extract the boardview of rampage extreme, we managed to solve many problems with this type of board. thanks again to @Dry_Ice777 for pointing me to the special chinese program which had the boardview included. now its time to solve another big problem. we need replacements for the vcore vrm mosfets. unfortunately i am only good at soldering. not more, not less. can anyone help to find working replacements which are capable enough or even better than the original ones ?

By far not an electronics expert, but here's my suggestion.

It looks like the current MOSFETs on the REX are these -> https://pdf1.alldatasheet.com/datasheet-pdf/view/347074/NXP/PH9025L.html

 

The closest I can find is this one -> https://www.mouser.be/datasheet/2/916/PSMN6R0_30YLD-2938884.pdf

It's the same logic level N-chanel MOSFET, same pin-out, same drain current of 66A and has a lower typical RDSon at 10V (5mOhm vs 6.3mOhm, though the they've measured it at different currents ?). Theoretically they should dissipate less heat with a lower RDSon. The total gate charge is also slightly lower so in theory it should be able to handle higher switching frequencies.

 

You could also go mad with these 100A+ MOSFETS https://www.mouser.be/datasheet/2/916/PSMN1R0_25YLD-2938902.pdf . Though, and this is where my knowledge about MOSFETs is lacking, it's capacitance is much higher so it might no be able to switch fast enough.

 

Hi. Sorry for the necroposting. I have a question about desoldering a Fujitsu capacitor on a Rampage Extreme in the DRAM area. I initially thought of sending the motherboard to some repair service for this, but it seems to be quite difficult to do in my city right now. Maybe someone could give me some tips on desoldering the Fujitsu cap? I have some soldering experience, but not with a hot air gun, which I understand is necessary to desolder this capacitor (correct me if I'm wrong)? Is it really that hard to desolder it without melting the plastic RAM slots? And do I also need some kind of additional heating from underneath the motherboard?

You need to heat the whole board to about 100-120 Celsius degree from the bottom. Second thing is, that you have to cover RAM slots at least using an aluminium foil or capton tape.

Heating from the bottom is necessary, it also reduces thermal expansion of the PCB during the resoldering.

You can use an electric grill with thermal control

1 hour ago, bartx said:

You need to heat the whole board to about 100-120 Celsius degree from the bottom. Second thing is, that you have to cover RAM slots at least using an aluminium foil or capton tape.

Heating from the bottom is necessary, it also reduces thermal expansion of the PCB during the resoldering.

You can use an electric grill with thermal control

Hmm.. So it makes sense to heat only the whole motherboard from the bottom? I was hoping to heat only the part of the board above which this capacitor is located. The problem is that I got this board with some kind of rubber feet glued to the bottom. And it seems they are glued quite firmly. I tried to gently detach them from the mobo, but I did not succeed. And I'm afraid I won't be able to heat up the whole board while these things are glued to it.

Edited May 26May 26 by silverspaceship

You have to heat the board and the area around the capacitor, otherwise it won't be even possible to unsolder it on such PCB, which has tons of copper. It simply spread the heat too fast. I did such replacement once and went good, exactly this capacitor around RAM area.

14 minutes ago, bartx said:

You have to heat the board and the area around the capacitor, otherwise it won't be even possible to unsolder it on such PCB, which has tons of copper. It simply spread the heat too fast. I did such replacement once and went good, exactly this capacitor around RAM area.

I mean, I was thinking about heating the board from the bottom with something like a hot plate (but small) that would cover the +/- capacitor area near the DRAM + additionally blowing hot air from a gun on top. Or is it still better to heat the whole board from the bottom and not just a small area?

You need to heat whole board from the bottom. Look for BGA soldering videos with preheaters to get the idea.

It does two things - heats the whole pcb and prevent bending of the PCB during soldering/desoldering.

Desoldering is the worst part, because non-lead solder has melting point around 230C. Then you have to remove the old tin and use the lead solder, which has melting point around 190C - it's much easier to solder.