Help for repair Gigabyte GA-7VT600-1394

[panegiricus]

Re: Help for repair Gigabyte GA-7VT600-1394

I must recap ALL the caps in the board? for 100uF i've a little bit fear to work with the solder, i would have the intention to leave them orignals

[PCBONEZ]

Re: Help for repair Gigabyte GA-7VT600-1394

Most of the time.....
.. you don't need to do the small 4 and 5 mm caps.
.. you don't need to do the 6.3mm under 220uF.

You should do all the questionable 8mm and 10mm caps.
You should do the questionable 6.3mm that are 220uF or more.

Questionable =
.. All of anything that has blown.
.. Any non-Japanese brands.
.. Chemicon KZG or KZJ
.. Nichicon HM or HN with date codes from 2001 thru 2004.

.

[panegiricus]

Re: Help for repair Gigabyte GA-7VT600-1394

Thank you , PCBONEZ, c_hegge, shovenose, you give me a clear answer to all the questions i posed.

[panegiricus]

Re: Help for repair Gigabyte GA-7VT600-1394

how can i replace 3300uF 1500uF and 1200uF supposing i would have an enhanced configuration?

[c_hegge]

Re: Help for repair Gigabyte GA-7VT600-1394

Do you mean what can you replace them with to enhance it? If so, just leave the capacitance as it is. It doesn't help anything and can cause problems.

[PCBONEZ]

Re: Help for repair Gigabyte GA-7VT600-1394

@: panegiricus
I'm not sure what you are asking.

Adding more uF doesn't help anything.
- People used to think it helped them but that is because they Lowered the ESR without knowing it when they raised the uF.

.

[panegiricus]

Re: Help for repair Gigabyte GA-7VT600-1394

c_hegge, PCBONEZ, excuse me, i wasn't properly clear. I mean for some "extreme" performance, like overclock (for what possible). It's a way to know if and how i can replace caps with a uF number, in any motherboard, with another.

[PCBONEZ]

Re: Help for repair Gigabyte GA-7VT600-1394

It is hard to make a statement that is always true for that.
What you can do safely will depend on the specific cap [series] you are replacing and what it does [it's job] on the motherboard.

Changing the uF doesn't help performance.
-> What helps performance is lowering the ESR.
You have to look in data sheets to know the ESR.

When bad capacitors first became a problem overclockers got the bright idea that using higher uF would help.
When their motherboard performance improved they thought the uF did it, but it wasn't the uF.
What they did was use higher uF caps that had lower ESR.
They thought it was the uF change that helped but what actually helped was the lower ESR.

You should keep uF the same but use lower ESR caps.
[Polymer mods are more complicated. I'm talking about electrolytic caps.]

You -can- lower ESR too much.
It [sometimes] causes a problem in the VRM called 'ringing'.

Lowering ESR by no more than 50% is ~probably~ okay for most mobo caps.
... But you need to know the ESR of the old and new caps to do that.
If you plan to do a lot with caps you need to learn how to find and to understand data sheets.
Google is a big help to find data sheets for common major brand caps.
.

[mockingbird]

Re: Help for repair Gigabyte GA-7VT600-1394

I'm recapping a Foxconn 945P7AA-8KS2. My problem is that I can't find any 6.3v 3300 capacitors in a 10mm width. I'm thinking of polymodding the VRM.

There are 7 KZJ 6.3v 3300 uF and 4 Rubycon MBZ 16V 1800uF. How do I know what's part of the VRM and what's not? Two of the MBZs are behind the parallel port, maybe they're associated with that area.

The board is also littered with 5mm Lelon caps, 8mm KZJ, and a single GSC cap near the PCIe x16 slot. Should I touch the Lelons and the KZJs? KZJ should be fine for that area of the board, no?

Also if I do mod the VRM what do you suggest I use? Or maybe I should just replace the 6.3V 3300uF KZJs with 6.3v 2200uF MBZs? I've got plenty of those around.

[c_hegge]

Re: Help for repair Gigabyte GA-7VT600-1394

If you poly-mod the VRM, use 1500 or 1800uF 2.5v polys on the VRM out and 330 or 470uF 16v polys on the VRM in. Otherwise, just use these

[mockingbird]

Re: Help for repair Gigabyte GA-7VT600-1394

Here are some pics:



The black ones are the KZJ and the blue ones are MBZ.
On the board are scattered 6.3V 1000uF KZJ, the green ones are 6.3V 470uF Lelon "RGA", and in between the coils on the side of the PCIe 16 slot are two GSC 16V 470uF "NK" caps. The tiny caps on the far left are a mix of Teapo SEK which I'm sure need not be replaced.

Higher res pics attached.

[c_hegge]

Re: Help for repair Gigabyte GA-7VT600-1394

Rubycon MCZ would be fine to replace the 1000uF KZG (https://www.badcaps.net/store/produc...products_id=46)
For the 470uF caps, these would be fine: https://www.badcaps.net/store/produc...products_id=51
The ruby MBZ caps already on the board can stay.

[mockingbird]

Re: Help for repair Gigabyte GA-7VT600-1394

Curious... The Lelon datasheet lists "RGA" as a general series capacitor with the ripple rating for my model at 230 or 270mA. ESR is not mentioned. Is it safe to use low esr caps here, or should I rather go with something like Panasonic FM or maybe even higher ESR like FC?

I'll be using Nichicon HM '09s for the VRM, I got a good deal on them with low shipping (No, not from Hong Kong).

[PCBONEZ]

Re: Help for repair Gigabyte GA-7VT600-1394

Wow.
I didn't realize you were still a beginner.

10mm 3300uF in 6.3v are common.
MBZ, MCZ, WG, FJ, FL, HM, HN to name a few.

Ditch the KZJ.

Leave the 4mm & 5mm alone unless they are 85C.
If you have to then LXY, LXZ, FC, PW or similar are probably fine but double check the ripple rating.

Check the NK to see if they are bi-polar. [Will be no negative 'stripe'.]
No data for GSC/NK but in several other brands NK is a bi-polar series.
If not bi-polar I'd use FM or better.

""How do I know what's part of the VRM and what's not?""
Use a DMM and trace the circuit.
16v will have one leg on [in common with] +12v to PSU and the other on a MOSFET pin.
The Vcore caps will have one leg on a MOSFET pin and the other on ground.
.

[mockingbird]

Re: Help for repair Gigabyte GA-7VT600-1394

Wow. I didn't realize you were still a beginner.

Certifiably non-certified, non-educated.

I managed to find a good source for the 3300s. I'm having a tough time finding the 16v 470s in HN,HM,HZ,KZG at Newark... They have lousy stock of these series. The GSC "NK" series are not bipolar. Notice how they're sitting between to coils, does this mean it's probable they're in a VRM schema and therefore should be low esr?

Thanks, I think I might trace them as I can probably get all the parts as polymer in stock whereas I'd have to wait another month or so till I order again from Digikey.

[PCBONEZ]

Re: Help for repair Gigabyte GA-7VT600-1394

Repeat after me:
"I will NOT buy KZG."
"I will NOT buy KZG."
"I will NOT buy KZG."
--- Both KZG and KZJ are failure prone.

For the 470/16v if you want better than FM you need to go to BCN or to Mouser.
- Mouser has HM & HN again.
At Newark the FM is here.
http://www.newark.com/panasonic/eeuf...vdc/dp/04M9014

3300uF 6.3 KZJ => .009 ohm ESR
If you aren't careful and choose polymer poorly it could end up being a downgrade because some polymer don't have ESR as low as KZJ and you would be lowering the uF too.
[Higher ESR -and- lower uF is possible even with poly...]
If you are going to use just 7x caps in Vcore and are doing the poly thing I suggest using 820uF poly with .005 ohm ESR.
.
Looks like you board was silk screened to use either 10x poly or 7x lytic.
If those unused poly pads [near the cpu] are actually connected in parallel with the 7x 3300uF then you have up to 17 places to put polys.
If that's the case then 10x560uF @ 0.007 ohms or 8x820uF @ 0.007 ohms would be consistent with factory poly'ed Intel, Supermicro, and Abit boards.

For the 16v poly.
If it's 4x caps I'd use 330uF or 470uF.
If it's 3x caps I'd use 470uF.
[Based on the factory same boards.]
.

[PCBONEZ]

Re: Help for repair Gigabyte GA-7VT600-1394

And yes,
Looks like a VRM type regulator for the PCIe slot.

[mockingbird]

Re: Help for repair Gigabyte GA-7VT600-1394

Repeat after me:
"I will NOT buy KZG."

I was getting desperate.

Looks like you board was silk screened to use either 10x poly or 7x lytic.

That's very astute of you. I was wondering indeed what all those little empty spots were for. I am a little troubled with this though because if you look at all the other empty spots (Quite a few scattered throughout the board), it seems as if they could be part of that VRM circuit and it is beyond me to attempt to decipher the schematic. It would be prudent of me though to browse Foxconn's site and see if I can locate a picture of this board manufactured with polymers.

[mockingbird]

Re: Help for repair Gigabyte GA-7VT600-1394

Not sure if this is the greatest example, but the models numbers are very similar: (945P7A[b]c[/c]-8KS2)

Notice they are using electrolytics in the empty spots.

[PCBONEZ]

Re: Help for repair Gigabyte GA-7VT600-1394

I was getting desperate.

That's very astute of you. I was wondering indeed what all those little empty spots were for. I am a little troubled with this though because if you look at all the other empty spots (Quite a few scattered throughout the board), it seems as if they could be part of that VRM circuit and it is beyond me to attempt to decipher the schematic. It would be prudent of me though to browse Foxconn's site and see if I can locate a picture of this board manufactured with polymers.

On the 'suspected' Vcore pads just check with a DMM and see if they are in parallel with the existing Vcore caps.

They used KZJ which are lower ESR than MBZ, WG, FJ, FL, HM and I think because of that they got by using fewer caps.
- KZJ are comparable to MCZ, HN, GC[samxon]
- HZ and GA[samxon] are one up from the KZJ 'grade' caps
Availablity considered the ~best~ replacement for KZJ is probably MCZ or HN[with good date codes.].

If you are using MBZ, WG, FJ, FL, HM for the scattered 1000uF KZJ then you might want to check for some unused pads in parallel with those and add about two caps if possible.