Quote:
Originally Posted by sc_rufctr
I was changing out the fuses in my old school stereo amp and I noticed the caps seem to be leaking.
Would you change these out? Some people argue that if they're working, you should leave them alone.
I haven't recapped an amp before but I am handy with a soldering iron. I've built various advanced kits in the past. (Power supplies and phone pre-amps etc.)
Also... Rather than replace them with cheap Chinese ones that may not be legit what would you recommend?
I don't mind spending a bit extra so I wont have to redo this at some point.
There are 4 total and condition wise they all look very similar. Note the slight doming of the top and the dark yellow shmoo at the bottom.
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I repair guitar amplifiers.
If the capacitors are older than 15 years they are 100% done. Normal usage for even 10 years they are done. Electrolytic caps have a service life for use. They also have a shelf life for non use which is very short. Guitar amps, tube amps, solid state HiFi, all considered wearable components. Easy to test, just see how much voltage they are storing when the unit is turned off. Even if they have a bleed resistor they will store some voltage.
Be cautious as stored voltage in a 50v cap can stop your heart. Do some homework on safely discharging them. You can make a discharge tool for about $2 yourself using a 5 or 10k ohm resistor and some leads. You can also discharge caps with a multimeter but risk blowing the internal fuse.
Do you ever get ghost notes, strange harmonics or has the equipment lost its brightness in sound. Bass sound deadened or muffled? Caps are done.
That may be glue at the bottom for vibration control. Using a toothpick is it hard or gooey? Gooey they are leaking. Do they smell like electronics? Get your nose down there. The plastic wrap paper at the top shoulder is showing signs of transparency (delamination from swelling). Your existing Topcon caps are about the cheapest Chinese Aluminum Electrolytics on the planet.
Take our time removing the old ones. If you can try to cut the leads on the cap side of the pcb. It will leave little stubs you can solder to versus desoldering on the backside and having the traces lift off the pcb which is a headache to repair.
F&T and SoZo are top brands for caps. They make a lot of mil-spec components. Vishay is excellent also. These three are considered the best in the industry. 4 high quality caps should run you no more than than $20 in parts.
I get my parts from Amplified Parts. They are fast to ship and carry a large inventory. Electronic components may be limited to shipping in country because of restrictions. Might want to find a local place on your side of the hemisphere.
https://www.amplifiedparts.com/