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First Recap attempt with a Mac Classic

MikMac

MikMac

6502
I have never soldered anything before. I have spent some time lurking these forms, reading recap experiences.

I watched a few youtube videos, and read a few websites about soldering SMDs.

I went to RadioShack, purchased a dual temp soldering iron, some solder, and a pair of curved tweezers. I dove in head first last night.

It took me about 2 hrs., but it was a success. I have about 8 more machines that I need to get working.

First few were a little sloppy.

First_try.jpg


Got the hang of it.

Second_try.jpg


 
It looks good.

Are you cleaning the board between removing the old capacitors and installing the new ones? It looks like there's some residue of some kind on the board. You should clean it after removing the old caps. That's when you have good access to the space usually under the caps. You should clean it again after installing the new caps, to remove any residual flux from the installation process. The second cleaning should be a much smaller job, as it's just to get a little localized flux removed. The thorough cleaning is the one that happens after the old caps are removed, because in that cleaning you're getting rid of any old capacitor leakage, etc.

 
What is the best method for cleaning the board?

I have not cleaned it as of yet, just tested to see that it worked.

 
Well I cleaned the board with some warm water with a small amount of dish detergent and a soft bristled tooth brush. I let it dry for 2 days in a warm dry location, put it back in the system and now there is no sound. xx(

What could be wrong?

I checked for any loose caps, but all seems ok.

 
I don't recommand cleaning boards with water.

Use pure or at last 98% pure Isopropyl alcohol: this evaporates almost immediately and is good for cleaning and removing fluid from leaking capacitors.

Here's how I work

- remove the old capacitors

- remove all old solder from the pads

- fully clean the PCB

- resolder new capacitors

- clean the array where you soldered and remove flux residue

 
Here are the steps I followed...

- removed old caps using soldering iron and de-solder suction device.

- removed all old solder

- cleaned pads and remover residue using 98% isopropal alcohol.

- soldered on new caps.

- put board back in system to test. Heard system beep, system booted, played 2 sounds. All was well. Shutdown, removed board.

- washed board with warm water and small amount of dish soap with a soft Roth brush.

- dried board in a warm, dry area for 2 days.

- put board in system, boot with no beep. Tried to play sounds, none.

 
Someone correct me if I'm wrong but I'm faily sure that the 1 µF 50v cap and it's 47 µF 16v neighbor are the usual suspects for no sound. Turn a keen eye that way and make sure everything looks clean and that your water didn't corrode anything.

 
I cleaned mine by putting the board into a dishwasher, using no detergent and without running the drying cycle. I let it dry for a few days, then did spot cleaning near the caps with alcohol and cotton swabs. I don't know if that is the best way, but it worked for me... :b&w:

 
I guess I'm lucky. I have 18 vintage machines in my collection and I've never had one that needed recapping. I have an LC 575 and a Macintosh TV that don't power on, but I suspect they both have dead analog boards. Then again, maybe my days of avoiding recapping are numbered.

 
I've just started recapping my P475. I've removed the old capacitors-two had started leaking, but I haven't bought any new ones yet.

Fortunately, I caught the two bad ones just in time. I managed to scrape the gunk off with a pair of tweezers, and no tracks were damged. The unfortunate thing, however, is that there appears to be some stuff stuck underneath the neigbouring IC (the capacitors, for those familiar with the P475's board, were the two 100 uf ones). I'm worried that the tracks underneath it will be damaged, and my soldering is only just good enough for capacitors-no ICs yet!

What is the best thing to clean it with, as, of course, I can't get the tweezers under there?

 
Looks like a nice recap job. For sound, you could also try playing through the 3.5mm jack, I seem to recall if you get no sound there, it might be an issue besides caps.

After installing new caps, washing the board is a bit excessive. I would just swab the areas that have excess flux with some alcohol. A little flux left behind is not nearly as harmful as acids from leaky caps unless you are using very aggressive flux, but I would only use rosin (some times in the solder core) or no-clean flux.

 
Good job. With more practice, you can hire yourself out to do recaps of logic boards.

Fyi: When uploading pics, lower the picture size or crop just the recap spots. It's a bit of a pain to view, especially for those of us with retro Macs.

73s de Phreakout. :rambo:

 
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