im new to this diy stuff, so i have a few concerns. is there anything inside integrated amps or amps in general that store voltage like the old CRT monitors where if you touch it you die?
If the PSU is an SMPS then the capacitor that stores the energy can be at ~400Vdc for 220/240Vac mains and ~200Vdc on the lower voltage 110/120Vac systems.
No and yes...
Depending on type of amplifier/power the capacitor bank can have letal voltage after power off and for some time.
Normally (and in normal operation) the capacitor bank should drain in about 30s/1 or 2 minutes but that depends on size of the cap bank/bledder resistor.
Just let it sit for a couple of minutes.
Assuming you are opening this up to repair it because somthing has gone wrong, it is still good measure to test the caps and discharge them before you play them.
you can test the leads of the caps with a dmm, being careful not to short them. If they test zero your good. If not you can discharge them with a resistor or I have done it with a light bulb. Dont do any of this with the unit plugged in.
how would u short them? by touching the leads together? what size resistor and how do u tell if the caps need replacing? lol no i know enough to pull the plug 🙂
I hate H&S zealots myself but here goes, just this once. Most of the advice given is only safe if you know what you're doing........ i.e. not safe for most people....for example:-
Shorting big value caps out can blow the end off a screwdriver and send molten metal into your eye. Discharging with a resistor is better but sounds like a good way of touching live terminals and defeats the purpose of discharging the caps to make them safe to touch.
Simplest way is to measure and wait for a while until there's only a couple of volts or less. Personally, to speed things up a bit, I make sure my hands are insulated (gloves) if there's more than 60 volts and use a 1k to 10K 1 watt resistor depending on voltage.
Shorting big value caps out can blow the end off a screwdriver and send molten metal into your eye. Discharging with a resistor is better but sounds like a good way of touching live terminals and defeats the purpose of discharging the caps to make them safe to touch.
Simplest way is to measure and wait for a while until there's only a couple of volts or less. Personally, to speed things up a bit, I make sure my hands are insulated (gloves) if there's more than 60 volts and use a 1k to 10K 1 watt resistor depending on voltage.
Buy an incandescent lightbulb, a lightbulb socket and three feet of romex. Connect one one wire to plus side of fixture one to negative. Strip 1/4 off the other end of the wire. Place lightbulb in socket. You now have a capacitor draining device. Touch the stripped ends of the wire to the leeds of the cap. It will drain instantly. The ends of the wire act like probes. Then test.
'Fraid you are going to have to read a sensible book on testing electronic gear. Listening to a hundred well-meant tips and easy-fix schemes is about as confusing as brain surgery with a scout manual.
Read up first, so you get familiar with terms, methods and basic theory. Try something like "How to test almost everything electronic" and also look around on Amazon for Randy Slones's "High Power Audio Amplifier Construction Manual" Neither are the latest brilliant works but make a good, inexpensive start in a field of much useless stuff. If you like to stare at the screen instead, there are brilliant Hobbyist sites like the ESP one
Read up first, so you get familiar with terms, methods and basic theory. Try something like "How to test almost everything electronic" and also look around on Amazon for Randy Slones's "High Power Audio Amplifier Construction Manual" Neither are the latest brilliant works but make a good, inexpensive start in a field of much useless stuff. If you like to stare at the screen instead, there are brilliant Hobbyist sites like the ESP one
ok one last thing...are the capacitors in an amp even big enough to kill you? what size capacitor is considered dangerous?
Read the label voltage rating. It indicates the approximate maximum potential across the + and - terminals. It is not a permanent charge and decays according to the circuit it is in. It's been industry practice for many years to fit "bleeder" resistors across the main power supply capacitors in professional amplifiers but this is not the case with lower power consumer and imported goods and particular types of transfornerless power supplies already discussed.
I believe the sticker .."no user replaceable parts inside"... gives an idea of what to expect, or not, in respect of your safety, once you open the case.
Then the physical size of the capacitor gives some idea of the sustained current capacity - just like batteries.
If you want to learn about what are considered safe or unsafe potentials, I think your Governmant is the authority there. In this and many countries, the words " LOW VOLTAGE" means'' <32V DC which is a nominal voltage for product safety laws to be based on. Some people are sensitive to much lower voltage, others need 90V so to feel anything, depending on skin moisture, contact area and pressure etc.
Nobody on forum likely has the authority to legally advise what are safe voltages. Consider anything inside the box unsafe until the potential is known "low voltage" at least. It still remains entirely at your risk in the event of injury etc.
I believe the sticker .."no user replaceable parts inside"... gives an idea of what to expect, or not, in respect of your safety, once you open the case.
Then the physical size of the capacitor gives some idea of the sustained current capacity - just like batteries.
If you want to learn about what are considered safe or unsafe potentials, I think your Governmant is the authority there. In this and many countries, the words " LOW VOLTAGE" means'' <32V DC which is a nominal voltage for product safety laws to be based on. Some people are sensitive to much lower voltage, others need 90V so to feel anything, depending on skin moisture, contact area and pressure etc.
Nobody on forum likely has the authority to legally advise what are safe voltages. Consider anything inside the box unsafe until the potential is known "low voltage" at least. It still remains entirely at your risk in the event of injury etc.
Once I'm done listening, I usually turn my amp off while the music is playing to fully discharge the capacitors. This ensures that no charge is stored.
Hope these links are helpful to you. Working with electronics is a bit like working around in an automotive repair shop or a wood shop - safety MUST be observed or bad things can happen. Considering your lack of training or experience I recommend you try to find a chum that lives near you to show you the ropes. There are usually HAM radio operators around almost everywhere - check the WWW for local groups.
TechTack - Lessons, Reviews, News and Tutorials: SAFETY PRECAUTIONS
Basic Car Audio Electronics
TechTack - Lessons, Reviews, News and Tutorials: SAFETY PRECAUTIONS
Basic Car Audio Electronics
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