You should connect it to where the Mosfet would have it's output pins...Quote:
Originally Posted by C-BuZz
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You should connect it to where the Mosfet would have it's output pins...Quote:
Originally Posted by C-BuZz
The three source pins of the Mosfet that is blown away are directly connected to the 4 drain pins of the second mosfet. The 4 drain pins of the second Mosfet are soldered to this large area under the Mosfet.Quote:
Originally Posted by C-BuZz
This is where you have to connect your external powersupply.
Alright, do I just connect the +2v to the 4 x Mosfet's drain area like shown in the pic?Quote:
Originally Posted by t024484
Edit: UPDATE: I've been doing some research on the power requirements of the memory & found that they use 1.8v / 35mA
Could I use a Zener Diode Rated @ 70mA 2V to reduce the 5v on my psu? & would this setup be in the ballpark to power the card?
Thx
C-BuZz
I see. That must be the reason why the stock frequency of that ram is relatively low. Thanks a lot!Quote:
Originally Posted by t024484
I'm also interested in the fact that you've mentioned that on your board they measured no more than 50 degrees. Do you know why is that?
It's really nice to have some technical specialists like you here.
The memory chips are drawing more than 1Amp under full load, times 8 chips.Quote:
Originally Posted by C-BuZz
The least the power supply should therefore be able to supply is 10Amp.
The zener solution will not deliver.
Alrighty, & I thought I was getting the hang of electronics. Well I was right if I was powering 1 of the 8 x memory chips lol.Quote:
Originally Posted by t024484
So the memory uses 35mA * 8 = 280mA or 2.8A? This is unloaded situation. When loaded this figure can tripple or Quad? Or mabye more..
I have a power supply with 40A on 5v rail, & I have another with 15A on the 5V. Will I be able to use a Diode (or mabye trimpot? or somthing) to reduce the voltage to 2V & still be able to deliver the required Amperage? If so could you recommend a suitable Diode that would be up to the task?
Is my drawing the correct location for the input voltage? Branched across the 4 X drain pins?
As always, thanks for your wisdom & all the help you have provided. True Scolar & gentleman ;)
If there's a glimmer of hope for my poor 7900 i'm willing to try it (if it's cheap or free lol).
C-BuZz
what about a vsense mod on the 3.3 volt rail on the external psu to give you the 2volts?
if it deliveres enough amps that is
Each memory chip draws more than 1 Amp, times 8 gives 10 Amp.Quote:
Originally Posted by C-BuZz
If you would use Diodes to lower your 5Volt supply, each Diode will carry 0.6Volt. This voltage-drop times 10 Amp gives 6 Watt for one Diode.
You will need al least 5 Diodes to drop from 5Volt to 2 Volt, so you have to get rid of 30 Watt of heat generated in the Diodes. You will need heavy Diodes for that purpose and a large cooling body.
Trimpots are out of the question.
You are right, every attempt is worth trying as long as it is cheap.
Now you probably start to understand why a switching regulator is so well suited for the job, it is extremely small and super efficient.
there's a schematic of a "ddr booster" in the motherboard mod section.
really simple (the second schema at the end of the first page)
able to deliver big Amps using a mosfet.
It may be usable for u, have a look ;)
for the topic :
http://www.xtremesystems.org/forums/...ad.php?t=64453
and for the post with the good schem :
http://www.xtremesystems.org/forums/...2&postcount=25
Don't know if it can go below 2.5V, have asked ;)
It does not go below 2.5Volt.Quote:
Originally Posted by bouc
But for the test, it will do to have 6 diodes, submerged in a glass with water and ice cubes (Nvidia on the rocks).
You will now fast enough if the memory is still OK.
This is the easiest and cheapest solution. Any diode capable of handling 15Amp or more will do.
Thanks for your help, but I now have the required power supply.Quote:
Originally Posted by bouc
Please confirm that my drawing is correct. Also where should I ground this circuit?Quote:
Originally Posted by t024484
Thanks
C-BuZz
Your picture is not so clear to me, but the large metal area under the unburnt Mosfet is where you should apply the 2 Volt.Quote:
Originally Posted by C-BuZz
There are several 3mm holes in the board with large areas around those holes that are all connected to ground
Good luck
With card out of the system sitting on the table running exactly 1.85v through the 4 drain pins I get a vmem reading of 1.85v & the mem begins to warm up ever so slightly, which I suspect is normal. However, when I plug the card into the mobo the volts drop to 0v??Quote:
Originally Posted by t024484
When I power the motherboard up I get the same flashing light with my mobo, searching for video...
Cheers
C-BuZz
Your added power supply will have a + terminal and a ground terminal. The ground terminal from the power supply should be connected (securely) to one of the ground points near the mosfet. The closer to the mosfet the better. You can't simply ground the supply to the chassis.Quote:
Originally Posted by C-BuZz
I've grounded it at the closest point near the mosfet. Ground is running back through my custom power supply.Quote:
Originally Posted by sluggo
With the card out of the system the current flows no problem, & I can get good readings on various points of the card. The second I plug it into the pci-e slot the volts drop to 0v :confused:
Edit: Ok this cant be good. When I power the card up & take mem reading its in the negatives !!!
Cheers
C-BuZz
Pulled some of the PCB and solder of form the 0.2 Vgpu stop :nono:
I solder the whires on, but it came of twice because I was reluctand to use glue, the PCB got pretty hot.
I Marked a littel Blue Cirkel where my whire pulled some of the PCB of.
I decidet to use the alternate soldering point marked with Yellow on the attached picture.
Everything worked Perfect, Card booted, And 0.05 and 0.1 Vcore was addet and resulted in 1.35 Vgpu :)
But 0.2 Volt did not work :(:(
QUESTION.
1. Did I kill the connection to 0.2 Vgpu when I "pulled" some of the PC and solder of the card??
2. How Can I acheave more then 1.5 Vgpu now when 0.2 Vgpu incresment
dosent work :(??
Thx for your help everybody :) Will poste some oictures of the card tonigth.
Ít works now :D
Just dident solder it the correct placew, was VERY tired after 16 hour values seminar at work
I put a single rectangular Thermaltake Copper heatsink over those 3 mosfets that get hot, and it still gets very warm. However I can now (just) keep a finger on it whereas without heatsink 2 of those 3 chips literally burnt flesh. Is this what other are experiencing?
The rectangular heatink covers all of the large mosfet, and 70% of the smaller 2 mosfets surface area. Does it matter that the 2 smaller ones are not 'completely' covered by the heatsink?
Also, do you guys think that Copper or Aluminium heatsinks are better for this application?
Im running at 601/800 with 1.4 penmod btw.
Ideally cover surface 100%, and its the old story about alu v copper, alu doesnt conduct heat as well as cooper but it dissapates it faster, so its swings and roundabouts, I feel for that purpose you are doing copper is better, but the alu ones should be ok as it was stock with none.
I have some small thermaltake copper sinks for the back ICs that get very hot. The thing is that both sinks are bigger then the ICs that I want to put them on and especially the real small one. The sink is basically "hanging" over on both sides, the longer IC isnt as bad as the real small one. So there is quite a big amount of sink on both sides not touching anything basically. Is that okay? I dont really have the tools to cut the sink in half or something so that isnt really an option as this point and I dont want to buy different sinks as these low profile TT sinks are some of the smallest I've seen and I have a brand new full package of them (8). So will that still be okay if the sink is bigger then the IC? Will it impact the benefit of the sink? Any comments/suggestions are welcome. Thanks!
When the voltage goes to zero, what is your 5Volt supply doing?Quote:
Originally Posted by C-BuZz
Diodes have a voltage drop that does not go to far beyond 0.7Volt, so if you measure 0 Volt, it can only mean that your 5Volt supply is going down.
The difference with the graphic board outside the computer is that there is no clock on the mem chips, and that no activities are taking place within the memory.
Once in the computer, the memory is adressed from the GPU and starts drawing real current.
If your 5Volt 15A power supply cannot deliver the current, it can only mean that one or more memory chips are ruined.
I am sorry, but it was worth trying.
The bigger the sink the better the cooling, as simple as that.Quote:
Originally Posted by smut
Be sure the sink is not touching any other component to avoid short cicuits.
t024484, would you also vote for copper over aluminium heatsinks for these mosfets?Quote:
Originally Posted by t024484
Thanks for the reply, I was thinking the same thing about the bigger the better but I wasnt sure if I was right. Thanks for the reply. And yes I will make sure they arent touching anything else. BTW i'm up to 700 on the core now since doing the 1.55v mod. I was at around 660 with 1.4v.Quote:
Originally Posted by t024484
I was thinking about putting sinks on some more of the ICs on the back of the card because I will have 6 sinks left over after taking care of the 2 lower ICs. Do you think I should go ahead and sink some of the others? I know it wouldnt hurt but just wanted your opinion on it. I also put a more powerful 90mm fan on my side window panel last night because the original thermaltake fan that came with the case (its a TT Tsunami) was shyt and hardly moved any air! I put a better fan in to push alot more air over the back of the card and to also move alot more air over my RAM since theres really no active cooling for them. So if I were to put sinks on the back of the card they would be getting ample airflow. What do you think? If I dont use them on the card I plan on finding some spots on my mobo (asus SLI prem.) to put them on.
OMG we have the same case, vid card and heatsinks.Quote:
Originally Posted by smut
What brand side fan did you upgrade to? I found the fan to be neither standard 80mm or 120mm.
Its a 90mm fan bro, thats why you found it to NOT be a 80mm or 120mm :D.Quote:
Originally Posted by xit
But anyway I had an older 90mm TT fan laying around from back in the day when Newegg made a mistake and sent me a 90mm fan instead of a 80mm fan. They didnt want it back so I kept it, I remembered I had it last night and decided to switch it out since the side panel air flow is almost non existant. I never noticed until I was working inside the PC with the power on and I could hardly feel the air blowing from the side fan. I dust it every day just about because it get can dust on it rather easily. I just wipe it off with my hand and it gets the dust off of there. But yeah anyway find a 90mm fan and replace the stock fan if you'd like to get better airflow blowing on your card/mobo! Althought the stock fan is near silent and the more powerful tt fan I replaced it with is louder the trade off is worth it. Its blowing ALOT more air now which can only help!
edit: the link to the Thermaltake 90mm fan I replaced the old fan with. IM sure you can get it at newegg! Link to TT site here with fan model!