Identify bad electrolytic capacitors

Here is a very rough explanation of how to identify faulty capacitors by eye - what to look for, and roughly how to use either the capacitance function of a multimeter (not every multimeter has this btw) or ideally an ESR (equivalent series resistance) meter to test your suspicions about the condition of a capacitor.
Generally speaking you're looking for bulging at the top of the capacitor, maybe even protruding tissue, or discolouration of the PCB and glue where the caustic or acidic fluid has seeped out.
About that glue - many larger capacitors in portastudios etc are glued to the PCB, the colour and opacity varies, but in most units I've opened its been beige and opaque. The first time I saw this I thought it might be leaking electrolytic fluid and I know from comments and messages that a lot of folks who are new to reapiring their own multitracker are making the same mistake.
Also please note that itis not always visually obvious which capacitors are shorted, open circuit, off value or have high ESR, checking requires testing. But becasue Capacitors are quite cheap to buy in large kits, if you can isolate a problem to a PCB or setion fo a circuit withless than 20 caps on it, it can be a time-efficient gamble to just replace all the capacitors in that circuit rather than troubleshooting on a component by component basis. I find that about 3/4 of the time "doign a recap"catches niggling electrical issues in old tape recorders etc, and even where it doesn't, because capacitors have a relatively short shelf life you're improving the longevity of the recorder.
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[@wellcord]

Thank you for the video. I’m trying to fix an old speakercraft amp. I’m so sorry about the fire you suffered-that is NOT an easy thing to recover from.

[@nobodytonobodysbusiness]

Thank you for not screaming into the microphone.

[@ezioauditore7629]

Thanks mate for the information

[@dftpunk]

Hi! I have exactly the same issue with glue from big caps flooding the PCB on my Tascam 424MK3. Personally, I am not sure that this is the electrolyte, but I will try to replace them anyway. Few questions:
- I see that the R7 resistor is cut from your board. What is the reason?
- The T902 transformer, do you know whether it is possible to find a replacement for it? After my FL display stopped working I immediately started to hear a weird sound of this T902 transformer. Not sure whether it is broken, but curious on whether the replacement is possible. I've checked the replacement manual and some people told me to not have a hope as this transformer is pretty unique.

[@eugenevanloo6205]

Great channel. Great help. Only thing is, i have this tascam 414 on which the sound keeps dropping out. It’s no power problem, it keeps going but the audio drops out and after a few seconds it comes back in only to drop out again for a few seconds. Any ideas?

[@Tetrakan]

Sounds like an intermittent contact. Check the faders are cleank, and the sodler joints below them are clean. If its not that somethign else might be dirty or have a bad sodler connection.

[@grantrennie]

I can see them either bulge or vent (stains on other parts or boards) and before I remove them to put them on the Atlas ESR tester I can tap them and feel/hear that they are dried out ..
If I take a cap off to test it, I usually just replace it anyway if it's a board of any age as they will go bad at some point..

[@Tetrakan]

Noted, thanks.

[@ethanweeter2732]

If you have low voltage, I have seen that cause a low voltage issue on a power supply. Capacitors are used to add delays into circuits. That the way you don’t get the full say 120VAC into a power supply before going to the transformer as soon as you turn the power switch on.

[@daniellambert1928]

would be nice if ( All Sick electro Caps ) were Swollen on the top

[@Edumunozbajo]

Hi, I got a hum noise on my tascam 424 when a playback , not while recording, any suggestion?
Thanks.

[@Tetrakan]

Could be a dissconected common ground cable, or a faulty eolectrolytic capcitor allowing junk from the ground to enter the audio path.

[@grantrennie]

@Tetrakan where abouts are you based? would you like to come along to a RUclips meetup in Scotland with big Clive ? Also would you be interested in a short trip to Boston USA to a meetup with several RUclipsrs ?

[@Tetrakan]

I’m in the Highlands. A Scottish meet-up is feasible/ appealing, the American one not so much, I’m skint!

[@grantrennie]

Have a look at big Clives discord

[@grant2082]

Couldn’t understand the accent

[@Tetrakan]

Couldn't give one whole shit!

[@ziliestarrive]

try increasing english comprehension