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View Full Version : 7800 GS AGP volt mods, 2 success 1 failure



liquidcooled
10-01-2006, 11:27 AM
I volt modded a 7800 GS AGP, and did the two pencil mods right, ( VDD and VDDQ ).

only when i did my 100k ohms VR to ground, no GPU voltage change when resistance it lowered.

I did the over current protection mod fine, i just cant change my GPU voltage.

Any ideas?

Site from witch i found the mod... http://sg.vr-zone.com/?i=3317

liquidcooled
10-02-2006, 09:39 PM
has any body done this mod here? please help!!!

RotorHead
10-03-2006, 03:43 PM
Do you have some pictures of the mods you did.......

The ones on VR-Zone dont show the ground points for the 100K VR.

boshuter
10-03-2006, 03:49 PM
Hi lc... lets see if we can figure out what went wrong.

First; are you ABSOLUTELY sure you removed the correct resistors for the overvolt protection?

Second; are you sure you have the vr solderd to the correct point?

Third; how are you checking voltages? Are you using the point in the pic to measure vgpu voltage? What voltages are you showing now?

Answer these questions and we will work from there, this is a pretty simple mod and it shouldn't be hard to get it working, has to be something simple.

PS: a 100K pot is very slow to change voltages, how far have you turned it trying to raise your voltage? It may have to go quite a few turns to show any change. ALWAYS turn the pot while the card is powered up and with a dvm hooked up to see the change.

boshuter
10-03-2006, 03:50 PM
Do you have some pictures of the mods you did.......

The ones on VR-Zone dont show the ground points for the 100K VR.

Any ground point will work. You can even ground it to a ground wire in a molex from the psu.

RotorHead
10-03-2006, 03:56 PM
Ok, cool, thanks bos....:thumb:

liquidcooled
10-03-2006, 04:03 PM
http://www.xtremesystems.org/forums/showthread.php?t=90461&page=2

There lost of back and fourth here on this web page above but no real answers, i even had to join there forum to try to get an answer.

Got the pic from here, and mine to show you what i did below.

My card is a BFG, And i heard that there have been some problems. Someone said to use a 250k VR to ground but this was not confirmed. i have scoured the web on this one and cant figuer out whats wrong.

yes im using all the reference points from VR-Zone, Memory mods are fine (500/800!!)just gpu voltage does not change, Watercooling is ready, just need to figuer this one out.

Vgpu=1.307_2d and 1.430_3d

Site from witch i found the mod... http://sg.vr-zone.com/?i=3317

boshuter
10-03-2006, 04:15 PM
Ok... looks like you have the correct points modded. Are you sure you are on a good ground?

It would help if you would answer the questions I asked above. How are you measuring voltage to the gpu? Is the voltage the same as you measured before the mod?

Going to a 250k vr is not a good idea. I'm suprised to see them recommend a 100k.

Main thing is... we need to know what voltages you are getting now, if they are different from stock, etc. Are you turnig the vr while the card is powered up and monitoring voltage? Does it change at all if you are doing this?

boshuter
10-03-2006, 04:17 PM
Sorry... just read your reply again and see the voltages you are getting.

Are you adjusting the vr while the card is powered up and monitoring voltage?

liquidcooled
10-03-2006, 04:29 PM
Yes powered on, and using a DMM to record voltage, 1.307v 2D 1.430v 3D, sorry i was editing my post to answer your questions, cause i have to doodle on the pic a little.

boshuter
10-03-2006, 04:34 PM
There are only a couple of possible problems.

1. You don't have a good ground or bad solder joint to the hot side of the vr mod.

2. If you are certain the solder is good and you have a good ground then chances are you are just not turning the vr far enough. A 100k vr may have to turn a lot before you see any change. For instance, if it's a 25 turn vr, you may have to turn 20 turns before you see any change in voltage. Be careful though, once it does start changing it will likely change quickly with minor turning of the vr. Thats why you want to use as low a value vr as possible for the application.

liquidcooled
10-03-2006, 04:51 PM
I tested the ground by putting my multimeter on the molex plug center ground and used a s-video shell ground point (Tested 00.00 resistance)

then bought 30 AWG wire fresh iron, solder, new 100k and 200k VR's. and the mod looks perfect.

Solder joints look great, very percise.

I have tried it a few times now with different wire VR's.

Have a 200k ohm on there now.

Is there a different point to put the VR?

joeMan
10-03-2006, 05:02 PM
Thanks for posting all this stuff guys. Interesting stuff, way over my head and skill level at this point but I feel I am headed here eventually.

Question: What kind of soldering kit do you guys use for this small scale of work? You guys probably have one of those magnifying glass things with a light mounted to it on the workbench too eh?

boshuter
10-03-2006, 05:10 PM
I can't help you with an alternate spot for the vr... they usually wouldn't have it posted on vrzone if it wasn't correct.

Have you tried turning the vr all the way down and still get no change? I sure wouldn't go with a 200k vr, the 100 is a much better choice. You have to figure if it's a 20 turn vr, then the 100k pot should change so much in each turn, a 200k vr has to change twice as much in each turn, making it a lot touchier when you get to the range you need.

Check your vr while it's off the card and watch the resistance change as you turn the pot... they don't always scale the way you think they will. Sometimes you have to turn them a lot to start getting any change, then it could change very quickly.

boshuter
10-03-2006, 05:17 PM
Thanks for posting all this stuff guys. Interesting stuff, way over my head and skill level at this point but I feel I am headed here eventually.

Question: What kind of soldering kit do you guys use for this small scale of work? You guys probably have one of those magnifying glass things with a light mounted to it on the workbench too eh?

Hey joe.... I use a digital Weller soldering station. You don't need that good of equipment, but I do a lot of soldering in my work. The lighted magnifying glass is mandatory.... especially at my age:D If you do plan on getting into it, a good iron is a great investment which you won't regret ;)

liquidcooled
10-03-2006, 05:21 PM
I just changed to a 100k and have been turning forever. Im getting a little nervous now cause like 15 turns and no change at all. should i just keep turning.

I checked the VR before i put it on and its good quality and accurate to scale. 00.00 to 93.450 in 20 turns.

I am lost now

boshuter
10-03-2006, 05:43 PM
I just changed to a 100k and have been turning forever. Im getting a little nervous now cause like 15 turns and no change at all. should i just keep turning.

I checked the VR before i put it on and its good quality and accurate to scale. 00.00 to 93.450 in 20 turns.

I am lost now

Yep... keep turning, just watch the voltage on your dvm. Once it starts to change it will change quickly.

liquidcooled
10-04-2006, 01:36 PM
Well turned it all the way last night....and then a pop, and black screen no video, card dead with no VGPU voltage.:yikes: :bonk:

So i guess this confirms the mod is not right for this BFG card as all the others seem to work with this mod fine.:rolleyes:

Its a damm good thing Im a electronics junkie or i would have been S.O.L. on a brand new BFG 7800 GS AGP in wicth i paid 350.00 for.:yup:

so last night was just terrible cause after the card died, so did my computer.
I put in my backup card (radeon 85000) and (Gforce 440 mx) and nothing. windows would not load up, with a NTLR missing mesage.:beat:

This morning was the break thru, not only did i get windows up and running, i Repaired my new card with parts from an old 7800 GS AGP that6 died 8 months ago, that i had on frozen water.
:deviltail :cool: :thumb: :D
So long story short i fixed my card, back up and playing games (thank GOD).

the part that was dead i have circled below on the pic in Green:thumbs:

a resistor marked 000 on the top. so i just took the one off my other card (DEAD) and solder it to my new card and......vola!!! BINGO BABY!!!!:rotflmao:

I was very happy after trouble-shooting this and repairing it i game myself a big pat on the back.:beer:

Im just going to stop tampering now unless someone can think of why this voltmod wont work.

these other yellow point are temping to me ta try out.

liquidcooled
10-04-2006, 01:40 PM
P.s I hope everybody here enjoys this Read, i love stuff like this


Below

Finaly got a good pic to come out, my camera is a digital sony cybershot 5 mega pixels
so not that great, but best i can do.

This is my gear in this pic this time showing where all the trouble has been, and still clean!!

liquidcooled
10-04-2006, 03:47 PM
pic of the video card

liquidcooled
10-05-2006, 04:08 PM
Played oblivion for 9hrs non-stop, and not one crash...weehoo.

Mem is at 1.6mhz/800, and thats just where i set it at, I dont know for sure how much higher it will go, but not there yet. what is a average for a memory volt modded 7800 GS?

And since i havent been able to get the VGPU mod to work, was wondering if Nhibitor will support my card?

RotorHead
10-05-2006, 04:31 PM
WoW.....good job on fixing the card.....:yikes: :thumbs:

nibitor might work.....I've never ysed it tho.....as the wife gets upset when something pops and I drain the bank account.....:beat: :lol:

BeeHay
10-05-2006, 05:07 PM
so last night was just terrible cause after the card died, so did my computer.
I put in my backup card (radeon 85000) and (Gforce 440 mx) and nothing. windows would not load up, with a NTLR missing mesage.:beat:


man, you wanna sell that 85000? :lol:

nice work man!

liquidcooled
10-05-2006, 06:30 PM
oops ha 85000 I wish eh!! 3D MARk 450 000+:lol:

I would try N hibitor but my floppy drive seems to be broken, It tells me over and over to format the disk, But it always stop on an error"Cannot format Disk".
Tryed coulpe other disks but no go.

Is There any other way to load your videocard bios from Dos without a Floppy?

boshuter
10-05-2006, 10:12 PM
Wow... that sucks:(

I did some reading and searching about the vgpu mod for this card and if I owned one, I don't think there is any way I would try it. I have yet to see anyone post anything positive about the mod on their card. It seems like there are a bazillion different versions of this card, not to mention there is a GS+ that even has a different core:coocoo:

I also double checked the pics of the mod on vrzone and your pics and can't find anything you could have done wrong, assuming the point you used for ground is good. If I were you, I would not attempt the vgpu mod on that card until someone comes up with a lot more reliable method ;)

Awesome work getting it back in service... I know that feels good:thumbs: A friend sent me a non-functional engineering sample X800pro card a long time ago, I just sat it on a shelf for a long time and one day I decided to look at it up close; I found 6 missing components and the card didn't have a power connector. Shimano and Viper John id'd the missing components for me and I ordered them and soldered them on and solderd an old molex off a psu to the power connection points and "viola"... the card worked :D I still use it for a back up

joeMan
10-05-2006, 10:25 PM
Great job on the repair. That must be a great sense of accomplishment. I just love it when it is darkest before the dawn in my computer adventures...the thrill of victory never gets old.

liquidcooled
10-07-2006, 08:50 AM
http://www.intersil.com/data/fn/FN9187.pdf

found this PDF on the ISL6568

With this i shoul be able to figure out how to add a variable resistor and adjust VGPU voltage

any theory's are welcome

liquidcooled
10-31-2006, 07:47 PM
Well i Do have a bit of a progress report. I guess the thing you have to keep in mind is that these cards never clocked well at least not like the 7600 did!!

Stock is 400/1200 or 400/600 (pathetic really) considering the rams are rated for 800mhz in the PDF!! Mine are samsung 552 k4J55323QG BC-14 256 meg chips

My initial overclock was 485/800 with normal VGPU voltage and the VDD (1.9v)and VDDQ (1.7v) mods done :) 3d mark 05 -7244 +/-

Then I did the VGPU mod, i found out how to do from the pdf, by setting the VRM table to 9, and i got 1.62v 2D and 1.75v 3D

Then i loaded the NGO optimized drivers 84.56 and the card auto OC'd to 570/800 and pulled a 3D mark 05 score of 8423 +/-

Then I did all my permanent mods and was able to oc to 648 (1.85v testing period + Vid 2 to ground) on the core but it wasnt stable.:smash: Mabey a capacitor mod will help?

So I ran 608/900 (for stability) and raised Vgpu to 1.85v 3D-VDD to 2.0v and got a 3D Mark 05 score of 8879.:chit:

I did'nt like the 1.85v so i changed it back to 1.75, and still does 608.:thumbs:

I also am in the process of Delta timmings mods, to see if theres room to improve there.:yup:

*EDIT* THESE POTS (memory) ARE JUST STACKED, THEY ARE NOT CONNECTED IN ANYWAY, SORRY IT LOOKS LIKE THE VDD AND VDDQ WIRES GO INTO 1 POT!!

liquidcooled
10-31-2006, 07:48 PM
I replaced All the resistors that are circled. and am hoping to do a Cap mod as well

liquidcooled
10-31-2006, 07:50 PM
This mod was to raise or lower the Memory voltage, and is set with a variable resistor

liquidcooled
10-31-2006, 07:50 PM
I looked at the PDF for these rams and the VDDQ also goes to the ram

liquidcooled
10-31-2006, 07:51 PM
Much neater now than it was in the lower pic (Week ago) I am still going to do more testing. (in my spare time Have to work everyday this week)

liquidcooled
10-31-2006, 07:53 PM
this is what it looked like before, When i was testing values and how they effected performance, mainly Variable resistors and pecil mods. Very un-organized to the look i know:coocoo:

liquidcooled
10-31-2006, 07:54 PM
My computer also has a secondary psu that turns on via a relay, to add 350w for the secondary hard drive, Fans, Exos2 unit and case sensors.:lol:

liquidcooled
10-31-2006, 07:54 PM
:cry: There you can see my Faithfull EXOS 2 Water cooling unit, I wish it was OCZ tho:rock: Mabey some day

I run this rig 24/7 i never turn it off.....I fold while im working, and i have never had electric shock theapy:lol:

liquidcooled
10-31-2006, 07:55 PM
And if i missed anything ill try and get to it later:")

What i really need is someone who's good with delta settings. Im wondering what to set to lower my geo/rop clocks ever so slightly, in little increments.

I set it to 50 delta and its OK but that just speed up the Geo/Rop to much and lowered the available OC potential. What i need is 156 delta???, but lowered it too much. any help please.

Thanx, im a little lazy after all this messing around.:hide:

liquidcooled
10-31-2006, 09:43 PM
Anybody know what this does?

liquidcooled
11-01-2006, 05:30 PM
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