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Old 02-14-2005, 03:26 PM   #8
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Join Date: Nov 2003
City & State: Αθήνα
Posts: 8,006
Default How do I do the cap replacement?

7. [ How do I do the cap replacement? ]

7.1. Please read the following links :

Topcat's HowTo - Overview of Recapping

Topcat's HowTo - Capacitor Removal

Topcat's HowTo - New Capacitor Installation

7.2. I want to learn good soldering, do you have any tutorials?

Yes, check the following links :

Elecraft Builder Resources (Click on Soldering Tutorial)

Apogee Kits Downloads (Click on ApogeeKits Free Illustrated Guide to Electronics Soldering)

The Basic Electronics Soldering & Desoldering Guide

University of North Carolina - Soldering Techniques paper
(Click on soldering.pdf)

There is no easy way to teach soldering. It is like an art. You have to learn what is a good solder joint and then practice to achieve it. One of the tricks is to get the hole wetted with a tiny bit of solder before you start to feed solder down the hole. Watch closely what is happening to the solder while you are working and you will learn.

7.2. I think I can ignore all the advice given on this forum and repair my board the way I like, itís gonna be ok right?

You might be lucky but probably you will trash the board. Badcaps members and moderators offer good guidance, please do not ignore their advice.

7.3 What values of caps should I use to replace the ones on the board?

You can either be safe and stick to the same values already on the board or you could use other values. You should be careful about decreasing the voltage, it is generally not recommended but it is ok to increase it. You can increase the capacitance (uf) as you see fit but the larger the voltage and the larger the capacitance, the wider and taller the capacitor. The larger cap may not fit in the place of the original cap. So if we give some examples :

1000uf 6.3V - You could replace with 1000uf 10V or 16V there is no problem.
330uf 25V - These are seen on some boards like Gigabyte. You can probably replace with 1000uf 16V like we did on a few boards without problems

Another consideration is cost. The larger the cap value, the more expensive it will be. No point to increase the cap values too much and pay more than necessary for a stable machine. The board will be perfectly stable using the same values of caps that were already on the board but this time using caps from a good manufacturer.

The safest thing to do is to keep to the same values as are already on the board. Use some 10V capacitors instead of 6.3V if you wish but trust that the board designers did know what they were doing when the designed the board.

7.4 There is a row of caps close together and I do not have small enough caps to fit the same number of caps there.

Generally a row of caps are connected in parallel so all the + leads of the caps are connected together and all the - leads of the caps are also connected together. You could for instance use half the number of caps but with double the value and only place the caps in every other capacitor position, leaving each position inbetween free. When you remove the caps however you must refill the holes of the positions you leave vacant with a little bit of solder to ensure that the circuit remains complete. When you remove the caps and dont clear the holes there is probably enough solder remaining there to complete the circuit but let's be sure and add a little solder to each hole while heating the solder pad of each hole.

Please note that it is not 100% certain that a row of caps is connected in parallel so this might not work in all cases.

Last edited by willawake; 01-21-2006 at 11:00 AM..
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