Newbie about to recap a FV25 - HELP

[etones]

Hi guys, i have a fudged Shuttle FV25 i would like to recap, however i am totally new to all this and have a few questions.

1) The caps on my mainboard do not match the ones in the kits given on this site.

The kit states:

3 x 4700uF 6.3v 12.5mm
3 x 3300uF 6.3v 10mm
5 x 1000uF 10v 8mm

My mainboard shows:

3 x 3900uF 10v 12.5mm
3 x 2700uF 6.3v 10mm
5 x 1000uF 6.3v 8mm

I have highlighted all the differences in bold, how sshould i procced, im inclinded to use the cap values on my main board.

2) Do I buy Aluminium Electrolyte caps? What is a good make? I am selecting panasonic right now but they do not have a cap that covers the 3900uF rated cap. (Using http://rswww.com - im located in the UK)

3) When picking caps and selecting voltages, do i select standard caps (eg 10v) or dc ones (eg 10v (dv)) ?

Thanks for all your help and a fantastic web site!

Taz

[willawake]

Re: Newbie about to recap a FV25 - HELP

hello Taz, i am from the UK but live in Greece.

the badcaps kit is developed according to what values of caps are available

I ran out of stock on the 10v caps that were needed to make the kits. 3300uF~4700uF 10v caps in a 12.5mm diameter are IMPOSSIBLE to find, and anything larger will not fit the board. I had to temporarily discontinue the kit because I didn't have a FV24 or FV25 motherboard to conduct experiments on. However, early last month, I got one of each, and did some extensive testing and research on it, and discovered the 10v caps were NOT needed. The positions those caps are in only have 2v MAX (VCORE voltage only) at any given time, and the voltage does NOT fluctuate. Why Shuttle used 10v caps is beyond me, but manufacturers have been known to do this in the past.

it is ok to increase capacitance but not ok to decrease voltage unless you know what you are doing. ok to increase voltage though.

TC certainly knows what he is doing

check the widths of the caps available at RS and see if they are gonna fit. might have to do some ugly bent caps/flat against the board etc...it is ok. i have not worked on that board but i assume sff = cramped.

RS have panasonic FC, great caps. i order from RS via greek agents.

electronic components / passives / aluminum electrolytic - radial / fc series 105oC

[etones]

Re: Newbie about to recap a FV25 - HELP

Many thanks willawake, caps have been ordered.

Now... to learn how to solder

Thanks again,
Taz

[Topcat]

Re: Newbie about to recap a FV25 - HELP

That about covered it. Yes, its safe to use 6.3v caps in the place of the 10v caps for the 3900uF originals. Upping the value from 3900uF to 4700uF and 2700uF to 3300uF is also perfectly safe as well. I've NEVER had a FV24 or FV25 be a dud, and I've recapped hundreds of them.

[willawake]

Re: Newbie about to recap a FV25 - HELP

the main points about soldering :

- a nice hot iron (if you have difficulties and have to heat for a looong time then it is inadequate) fast in and out at high temp is safer than looong heating.
- adding solder to the existing joints before you remove the old caps
- take your time, ease the caps out and ease them in. if you have difficulty then modify your technique. do not force things, wait until the solder is melted properly.
- if you get tired or are rushing to finish then leave it for another day. rushing at the end and killing the board gets you nowhere.
- support the board properly in a makeshift board holder, like two wood clamps upside down clamped to the desk, badly supported = the iron will slip and damage the board.
- dont worry about if you made a good connection, heat the lead and the solder pad at the same time and add some solder. of more concern is not forcing caps in and out.
- dont short your solder joints to nearby pads or components.
- make a diagram of the existing caps and their polarity. double check your installation with the diagram before you power up.

[bushytails]

Re: Newbie about to recap a FV25 - HELP

"- support the board properly in a makeshift board holder, like two wood clamps upside down clamped to the desk, badly supported = the iron will slip and damage the board."

You know, to this day, I still use my biological-structure-with-outer-fabric-coating board holder (read: my knees and a pair of jeans) with no problems.

--Randy