• Hello MLAers! We've re-enabled auto-approval for accounts. If you are still waiting on account approval, please check this thread for more information.

Decided to try my hand at recapping. Guidence needed!

G

Guybrush3pwood

6502
I have a 580 logic board collecting dust and i've decided to put it to use. I have a couple functioning systems that I want to recap, but since I'm new to the process, I want to practice first.

I'm using the instructions detailed here:

http://www.classicmac.net/reference/caps/

My first question is, how can I tell what replacement capacitors I need to buy? Is it just a matter of matching voltage or do these other numbers and letters hold significance?

 
The value is important, but the voltage is up to you kinda.  like say 33uf or 47 uf is a value you need to match but the 16 v is voltage you can get matching or higher.  Higher just means it can allow more (usually costs more).  You can use other types of capacitors like tantelum which seem not to go bad as they do not have electrolyte in them.   Like you will never usually see a Quadra 700 have an issue as its all tant caps.

 
Doesn't matter, as far as your are matching uf and voltage you are good to go, but clean the board first.

 
I use an old toothbrush, warm water and soap,the second step only water, then let the board rest for a couple of days.

 
Those little can caps are surface mounted. So that requires a different method of dealing with them. Also it is best to replace them with solid state caps like Tantalums or Ceramics.

The µf rating has to match, you can not change that. The voltage rating you can go for a higher rating if you like. They are already at 16V, you can go as high as 20V. The problem here is the higher the voltage, the physical size the cap gets and it gets to a point where it will not fit on the space the cap is on. To make it easy, just leave it the same - 16V.

Look at the video on Ferrix97's restoring a LCD panel where he changes the caps on it.

The thing is this, you need to check for trace rot. After you remove the cap, you need to clean up the cap goo that was under it and check the traces with a multimeter to make sure they are OK.

Wash the board with distilled water and ammonia. Then rinse out with distilled water and then rinse off with high proof isopropyl alcohol. Under the caps when you remove them - use acetone and then alcohol with a q-tip or tooth brush. Let it dry out and put in the cap.

Here's Ferrix97's Link for his video. Study it. Study it several times before making that first move.

https://68kmla.org/forums/index.php?/topic/23893-powerbook-145b-also-for-140-160-145-display-capacitor-replacement-video-tutorial/

 
DO NOTE THIS!!!!

THIS IS ONLY IF YOU ARE USING TANTALUM SOLID STATE CAPS...

Those can caps have a mark on one side, that says that side of the cap is Negative "-". But on Tantalum Solid State Caps, the mark is reversed to the Positive "+" side! So you have to install them in "reverse". If not - they have been known to explode like a firecracker!

Of course, if you are using Ceramic Caps, they are not polarized, and they can go in at any direction.

 
I'm doing this before any leaking has occurred. I just don't trust myself with a multimeter enough to check traces. I've only ever measured batteries.

I've looked up Tantalum caps but I can't figure them out. They don't have leads. How do I attach them with solder if they don't have wirey little legs to attached them?

 
Then you should use Ceramic Caps - SMD/SMT Style. You can use leaded caps but you will be doing a lot of write bending and cutting. But all caps have leads; it is how the lead is shaped and connected that makes the difference. Perhaps these pics will help.

SMTSMD-Caps.png.017ed1e2d40a8cd5ec5fce63dd62d77f.png


SOLDERING.png.fd09d318979d3f58757be158dca1cc8f.png


(EDIT) NOTE: If you do this - replace a few caps at a time and test the board at each batch of a few caps this way if something does break, you can go back to the last caps you did and check your work and fix your mistake. I say, check after every 3 caps done. If if works, do the next 3, and so on. If and when it fails, you know which three to look around on instead of going crazy and checking the whole board.

 
Last edited by a moderator:
I would not go to ebay for caps. They are not trusted sellers and there is little or no guarantee of the caps when you get them. And there is a lot of "counterfeit" caps floating around on sites like ebay. You need to go to a trusted seller like: Mouser, Newark/Element 14 or Digikey. I have bought from all of them before and they are a lot cheaper than ebay.

There are a couple of forum members that sells caps as well: Uniserver, and Trag. CompuNerd also sells caps but for LC TDK-PSUs but you are not dealing with LC TDK-PSUs... They buy caps by the ton for their recapping services and do sell some caps to the forum members. You just need ask them, their prices are usually lower than everyone else's and they are trusted sellers of their services. You just have to PM them and talk to them about what you need. I bought caps from Trag before and will buy from him again. Same with Uniserver and CompuNerd; money's tight right now so things will be put on pause for a while for me.

When you solder the SMD/SMT cap on the logic board, use a pin or a screwdriver to hold down the cap on the board while you solder the cap's lead to the trace. Use a thin tip - low watt soldering iron like 15watts. Space is going to be tight. So take your time with it.

 
Oh, yeah, I don't care where they come from, as long as they're legit. Do these people you mention have stores that I can order from or are they just forum members?

 
digikey and mouser are both just electronic stores online.  I like mouser as you can enter values and get a huge list of capacitors.  The  only thing is make sure the ones you order are "in stock"  as the estimated date is never even close.

 
A little unrelated to where the discussion is at the moment, but:

I would highly, highly, highly recommend you buy one of these:

http://www.ebay.com/itm/301828051023?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

It is very easy to use and gives professional results, with very little chance of damage to the traces on the motherboard.  It made recapping my LC550 motherboard a very smooth and easy experience.

<opinion>

There are other methods of removing the caps, but when the correct tool is less than $40 shipped why risk damaging any of your motherboards?

</opinion>

As far as choosing replacement caps, our man Elfen knows what's up  :)

 
You must log in or register to reply here.

Similar threads

H
Mac Classic II black screen and low voltages?
Replies
6
Views
252
wthww
wthww
sircabulon
IIci/IIci/IIcx trouble
Replies
9
Views
2K
sircabulon
sircabulon
zigzagjoe
Macintosh 68060 Redux
4 5 6
Replies
103
Views
13K
croissantking
croissantking
jazzius
Problems with Quadra 610 ; Dead Board and Unusual PSU
2
Replies
21
Views
2K
chiptripper
chiptripper
Irinikus
My 21" Apple Studio Display (Blueberry - CRT) Restoration Project
Replies
6
Views
1K
Powerbase
Powerbase
Back
Top