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ej2095

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Found my Amiga 1200 from 1993 in a cupboard but just the board and a power tower back plane attached.. (Think i got rid of the tower about 10 years ago hind sight a wonderful thing eh lol)

Fired it up and it worked. But studying the board there's a cap under the floppy that has snapped of lol just the bottom bit left of it..

Thee easy to remove and replace i assume?
 

disco

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Cap is easily replaced, just make sure you're using soldering iron with temperature control (no more than 150 250 degrees C for no longer than 2-3 seconds).

BUT... if the cap leaked then you have serious issue which requires proper cleanup and damage repair. It would be best if you could post a closeup photo of that area on the board.
 
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demolition

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Unless it has some really exotic solder, it won't be melting at 150 deg. C. 300-350 degC is usually a good temp range for soldering.
 

disco

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My mistake, thought 250, not 150. Of course, it all depends on melting point of the solder you're using. For Amiga I would choose the solder with lowest melting point as possible because of the temperature sensitive SMD components on board. Also forgot to mention it's recommended to use flux for SMD components.

It's all to prevent doing this to Amiga. A guy tried to repair his own Amiga after cap leakage and ended up making bad situation even worse, destroying a pad in the process.
 
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Bryce

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The temperature depends on the type of iron you are using, its thermal mass and what you are soldering. The specified soldering temperature for an SMD electrolytic capacitor is usually around 250°C for 30 seconds, but this is the reflow oven temperature where the entire part is brought up to this temp. For soldering with an iron you should have the iron set to around 350 - 360°C. As soon as the iron touches the cold contacts and track, the temperature drops rapidly, so the part never gets close to the 250°C unless you leave the iron connected for about 10 seconds or more.

The pad damage in the video above can be caused by several mistakes: Keeping the heat on for the pad for too long (melts the glue under the pad). Pulling the component up before the solder is fully melted. Or the leaked electrolyte may even have weakened the whole thing beforehand.

Bryce.
 

disco

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Thanks Bryce, it's good to know that 360°C for 3 seconds won't fry it.
 
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