Can You Drain The Caps In Hi Fi Equipment For Repair?

Warning! Belch those Capacitors!

Working inside a tube amplifier tin be dangerous if yous don't know the basic prophylactic practices for this kind of work. If y'all aren't prepared to take the time to larn and utilise the right precautions to keep yourself safe, don't work on your own amp. Y'all can seriously injure yourself or get yourself killed! This is not intended to be a complete guide to prophylactic in tube equipment, just to hitting the high points equally refresher for those of you who have some experience. The best way to learn the requirements and practices for condom in tube equipment is to find someone who will teach you ane on i.

Basic REQUIREMENTS

UNPLUG Information technology FIRST: Pretty self explanatory. Practice not, ever, e'er, leave the equipment plugged in and start piece of work on it unless you specifically intend to make some alive-voltage measurement. Leaving information technology plugged in guarantees that you lot will have hazardous voltages inside the chassis where you are about to work. This is like setting a trap for yourself.
Permit IT DRAIN: If the amp has been turned on recently, the caps will still have some high voltage left in them afterward the switch is turned off. Let it sit for v minutes after you turn it off.
SUCK IT Dry out: When you lot open up upwardly an amp, you need to drain off any remainder high voltage. A handy way to do this is to connect a shorting jumper between the plate of a preamp tube and footing. This jumper volition drain whatever high voltage to ground through the 50k to 100K plate resistor on the tube. To do this successfully, you will demand to know which pins are the plate pins. Look information technology up for the amp you're going to exist working on. You lot'll need to know this for the piece of work anyhow. Leave the jumper in place while you practise your piece of work (high voltage electrolytic caps can "re-grow" voltage like a battery sometimes. Really.) Remember to remove it when you finish your work.
Exam It: Accept your multimeter and ground the (-) lead. Probe the high voltage caps and be sure the voltage across them is down, preferably to less than 10V.
Push IT BACK Upwards First: Take the shorting jumper out. Put the chassis dorsum in the cabinet, making sure all of your tools, stray bits of solder, wire, etc. are out of it. Y'all don't have to actually put all the screws and and then forth back in if you believe more piece of work might be needed, simply make sure that the chassis is sitting stably in the chiffonier and won't fall out. At the stop of a listening exam, either continue buttoning upwardly if you're done, or go back to UNPLUG It FIRST.
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