Power supply recap help please

Talldog

Pain in the ass
Gonna make my first attempt at actual electronics work. I'm going to recap the PS for my TAC Scorpion. Easy question: I've seen around here about dissipating caps before you mess with them. What's the deal with that? Also, it looks like there are only 5 caps to replace. 4 giant ones and one medium one. Where do I look at them to see what they are so I can get new ones. Thanks in advance.
 
I'll leave the discharging questions for someone more experienced, but you'll be looking for two values that you should see right on the caps themselves, capacitance usually in microfarads ("uf") and voltage ("V")...so if your cap says "6800uf 25v" you're looking for a 6800microfarad, 25 volt cap. You'll want to measure and note the physical size of the caps themselves while you're looking at them, as you will most likely have various size options for your new ones.
 
here's video , gives you basic idea:

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the right way to discharge capasitor is to use a lead with clips and a power resistor in series (something like 10K - 50K resistor rated at 2W would work) . Also it's a good idea to actually check the DC voltage across the cap with multimeter and then re-check after discharging it, or even monitoring voltage while discharging.
It takes some time to completely discharge a charged cap through a resistor.

As I do this pretty often, I 've made up a special discharger jumper with 100K/2W resistor in series, see attached picture.

Unsafe and pretty DUMB and danm dangerous method is simply to short the capacitors terminals. Some folks do so and think it's fun .... :spank:
 

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You would do well to look at Nichicon PW series caps as theya re for power supplies available at Mouser & Digikey.

You might also want to increse voltage ratings. You can go to 50V in same size can as the 25V units as today's caps are better and smaller.

Discharging is a good idea but if the unit has been off for some time chances are the caps have discharged.

Listen to Dr. Zee on this one.
 
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