Can someone do the opamp mod to my DDR Booster?

[Tibu]

I'm sick of the voltage drop under load. Can someone that has done this mod do it for me for a reasonable charge?

[persivore]

I'll do it for you for the cost of the parts (which will be very low, and possibly free if I can find a working opamp on a dead motherboard!), plus shipping costs.
Edit:found an opamp, so I can do the mod for the cost of shipping.

[bh2k]

Can someone link me to this mod?

[persivore]

Can someone link me to this mod?

http://xtremesystems.org/forums/showthread.php?t=50444
I've been meaning to write up a mod-guide for the mod and do some testing of it, but I haven't got around to it yet.

[Dissolved]

if i knew how to do it, i would and make a guide.

my booster even with a 10k pot drops .2v from windows boot to windows load.

[CaTalyst.X]

Ill do the opamp mod for u for the standard 30.00 fee including return ship..

-CaT

[bh2k]

Does someone want to explain to me what this mod is so I don't have to pour through that thread?

[bh2k]

Well I read it and I don't exactly understand it, but I bumped the thread with some high res booster pics.

[persivore]

Well I read it and I don't exactly understand it, but I bumped the thread with some high res booster pics.

Thanks for the pics. I'll write the mod up next week if I get enough time :)

The mod uses an opamp to provide regulation for the Vdimm supply the booster gives out (because unmodded, the booster has no regulation and just relies on MOSFETs to keep the voltage stable). A variable resistor used as a voltage divider provides a reference voltage, and the opamp regulates the output from the MOSFETs on the booster so that it exactly equals the reference voltage from the variable resistor (within a few mv).

[bachus_anonym]

@ persivore,

If you still need couple more photos (better quality than bh2k posted, tbh :D) then here they are, attached below :toast:

good luck on your guide :thumbsup:

[bh2k]

:( well bachus, if I had one in front of me I'd take nicer pics :(

[bachus_anonym]

:( well bachus, if I had one in front of me I'd take nicer pics :(
Don't take it personal, please... :toast:
I had those photos taken long time ago, just right after I took it out of the box...

[bh2k]

I'm not :D Im just saying.

[Ubermann]

Persivore can you tell us what parts to order to be able to make the mod ?

[persivore]

Persivore can you tell us what parts to order to be able to make the mod ?

I'm thinking of writing up 2 mods for the booster - a basic one, and a more complicated one.
For the basic one you will need an LM358 opamp, a 100nf capacitor and a 10k variable resistor (any value resistor between 500ohms - 50k should work fine however, or you could use the origional variable resistor from the booster)

The more complicated mod will use a regulated voltage to provide the reference voltage for the Vdimm, so should provide a more stable voltage. For this mod, as well as the things above, you will need a 5.1v zener diode, a 470ohm resistor and another 100nf capacitor.

Edit: if you want to limit the voltage so that it is adjustable between 2.5 to 4.3v, include a 4.7k and a 15k resistor (if you are using a 10k variable resistor, the values need to be adjusted if a different value VR is used)

Update: I've been doing some testing and I get a droop of 0.01v at max load with the voltage set to 3.5v with 2 256mb sticks of RAM. This could be due to voltage losses in the cabling I'm using tho, so the droop might be less. I should have the guide written up over the weekend.

[Ubermann]

Awesome work!
Mine can drop from 3.95 to 1.83 as it is now.

Again: Very god job!

[Dissolved]

i could really use this, as i dont wanna have to buy a new mobo for the venice :\

[Ubermann]

How much ampere for the capacitor ?
Should i use 100 μA to 1 A or 1 μA till 10 mA ?

[persivore]

I've posted the mod here (http://xtremesystems.org/forums/showthread.php?p=794264#post794264)


How much ampere for the capacitor ?
Should i use 100 μA to 1 A or 1 μA till 10 mA ?
A general puropse 100nf capacitor should be fine. I'll link you to some if you want.