voltmod of ti4200 50% done need advice

[saaya]

ok, so i have those gpu and mem meassurement points soldered to some cables, all i need to do now is check the voltage between them with a multimeter while the system is powered on right?

what do i set my multimeter to and where to i plug the cables in?

http://www.produktinfo.conrad.com/datenblaetter/125000-149999/129402-sp-01-en-lcd-digital-multimeter_vc_444.pdf

features:
10A non fused
ma terminal fuse 0.3A 250V
voltage VAC 200-600V / VDC 200mV-600V
Current DC 200µA-10A
resistance range 200Ohm-20M Ohm

is this multimeter ok or should i get a better one?

[saaya]

this is my multuimeter

[saaya]

is it ok if those two contacts are soldered together? i think they were already touching before but im not 100% ... just checking.

[Major]

NO its not ok if those two points are soldiered together !!!! that would be a dead short on your Vgpu voltage.

If that is a cap that your measuring the Vgpu at make sure that the two leads of the cap are not the two points that are soldiered togther, that would be very bad ! hehe

Your meter is fine.

You should have two jacks on the front that are red one is for current and will be marked VA DC or something like that. the over will be marked V DC/AC or something simular. Use the jack that is marked VDC and the black (Ground) Set the Meter to 5vdc scale or the next smallest range. If it is a autorangeing type then it will automaticly set it to the apropriate scale.

[saaya]

no no, the two points of the cap are not soldered together, there are actually 3 points, its like this:

those two points are very verya close to each other, and i think theyx were already making contact before, but im not 100% sure... theres a nother pair of those points on the card and those are making contact...

now how do i meassure the voltages? :(

doesnt it matter what point is ground and which one is red?
ive seen a lot of pics in diferent forums and they are all different. some say red (+) contact left, some say right, some say use the second point as ground, some say i have to use the ground point near the vga connector... :/

[saaya]

is the multimeter really ok? cool it only costs 5€ :)

here, you can see it pretty good on this pic... i think they were already making contact before right?

[Major]

black lead is ground, the red lead that is connected to the multimeter on the Jack labled VDC is the positive and should be used at the test point on the card.

[saaya]

i still dont know what to do. check the pic above. 2 points, i have them both soldered to a cable, but now what? wich point should be connected to the black and wich to the red cable of my multimeter? :(

see, the prob is there are 2 test points... and i dont know wich one is actually "the" test point and wich one is just another ground point :(

[Major]

It wont matter if you get the two leads reversed, it will just show as a negitive DV voltage if you do on the Multimeter. Just use the two wires you have attacted and connect them two the two leads on the multimeter.

[saaya]

the resistance between pin11 of the voltage control chips are 100 and 123, so i measured the resistance between all those 4 pins and pin11 of the control chips and it seems the right and the upper one are ground spots since they have the same resistance to pin11 as the ground points close to the vga plug... but im not 100% sure... ill wait till i get a reply of sys or bowman or anybody else who knows it for sure :/

[saaya]

are you sure? it doesnt matter wich one is ground? cool!

[saaya]

the resistance on the vmem points is 133, on the vgpu points its ... 13??? :confused:

[Hell-Fire]

Originally posted by saaya
is the multimeter really ok? cool it only costs 5€ :)

here, you can see it pretty good on this pic... i think they were already making contact before right?

No, those wires are coming off a cap on the front of the card that gives the VGPU volt readings. One wire represents the positive (red probe) current, while the other wire (black porbe) represents the grounding point on that cap so that current will actually flow.

Each cap leg on the back of the card where you measure VGPU and VMEM from needs to have a separate wire.

If you want...I will "borrow" Sysfailurs pic and edit it so you can follow it better since I have done this mod before.

Fire

[saaya]

no, no look:

2 and 3 are the measurement points of the vgpu and i soldered each of them to a seperate cable. i dont know what 1 is but im pretty sure it was already making contact to 2 before...

the resistance between 2 and 3 is 13 (ohm?) dunno what i set my multimeter to... the resistance between the vmem measurement spots is 113(ohm?) so i thougt 13 on the gpu points is a bit low... is it normal? maybe it changes once i fire up my system?

[Hell-Fire]

Originally posted by saaya
no, no look:

2 and 3 are the measurement points of the vgpu and i soldered each of them to a seperate cable. i dont know what 1 is but im pretty sure it was already making contact to 2 before...

the resistance between 2 and 3 is 13 (ohm?) dunno what i set my multimeter to... the resistance between the vmem measurement spots is 113(ohm?) so i thougt 13 on the gpu points is a bit low... is it normal? maybe it changes once i fire up my system?

Wait, you are taking your ohm readings at the cap legs and not on the ic's themselves?

What ic's are they...2 SC1102 or SC1075?

Regardless, thats sound pretty damn close to what they should be with the card unplugged from the rig.

The resistence wouldnt change after you fire up the rig...unless you have added the VR already that is..so dont expect it to change...you would be reading voltage after card is powered up.

[saaya]

nope, no vr yet. and that gpu resistance reading is ok? pheeew ok then :D

the gpu mem ic is labeled sc1102cs the vmem ic is labeled sc2602s (cant find any specs but there seem to be other cards with this ic and it seems to be the same as the 1102 from what ive read)

resistance of pin11 of the gpu ic results in 100 ohm , pin11 of the vmem ic (sc2602s) results in 124... thats the same everybody with the 1102`s got as well, so i assume the 1102 and the 2602 are practically the same.

[Hell-Fire]

Ok, then you can basically follow Sys and MrIcee guides to this then.

***IMPORTANT***

Take a voltage reading with the card plugged in so that you have the base voltages for you card, and can see after the initial mod is done that the voltage did indeed go up a bit. The voltage should go up after the initial phase is done before you even start fine tuning it.

The only ohm reading you care about is the one before you add VRs and at the IC pins 11 & a ground point for each IC.

Looks like you got 100ohms and 124ohms...they look dead on to me. So, multiply those ohm readins by 20 and set your VRs to that measuremnt before mounting them to the ICs.

Are you using 5k or 10k VRs? Doesnt really matter..just curious as how fast the voltage goes up depends on the VR used.

Important to set the VRs to the correct ohm action that you got from the equation (20 x measured) before sodlering. Also, dont make the mistake of say using the middle pin on the VR with the red probe from meter when setting the ohmage you want and then soldering the black ground wire to it. Get what I mean by that?

Make sure if you choose not to use pin 14 as the ground that what you ground with for the VR is actually a ground...you need to get a measurement using pin 11 and anything you plan to use as a ground so you can see if it is grounded or not. If you get ohm reading..grounded...if not..then not..lol. :hehe:

Plug card in, fire up riggy, take voltage measurements..you should see higher readings now than beofre mod..then just turn the VR clockwise to lower resistence and raise voltage. Turn slowly as it can start slowly going up only to start jumping quickly.

[saaya]

i already bought a bunch of 5kohm vrs, well its like that... im building a tec/watercooling system for my video memory, the cold plates will cover those measurement points so i soldered the cables to them already. ill mount the cold plates of the tecs tomorrow, just after i soldered the vrs on the card. maybe till mount he waterblocks for the tecs tomorrow as well. on saturday it should all have dried well and ill insulate the whole thing with neoprene and make a test run.

i had to take the gpu waterblock off to solder and cut the cold plates for the memory in the right shape, so i cant check the voltages yet since i have no gpu cooler mounted on the card right now...

thx for the help guys :toast:

[Hell-Fire]

Good luck m8.

[saaya]

damn soldering on the memory controler chips is harder than i thougt! best way is to get a tiny drop on the cables end and hold it to the leg you wanna solder it on and then hold the solder iron on it carefully until it melts.

big thx for that tip pc ice! :toast: