# Is an old PC PSU "safe" to mess with?
**URL:** https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097
**Category:** Factual Questions
**Created:** [February 20, 2023, 6:29pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097 "2023-02-20T18:29:16Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)
#### Post date: [February 20, 2023, 6:29pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/1 "2023-02-20T18:29:16Z")
I gave my 7 y/o an old Dell PC to take apart. He’s steadily worked his way to where the last thing out was the power supply. I opened the PSU so he could look inside, but I was hesitant to let him poke around inside because I know there are capacitors etc. that could be dangerous.
It hasn’t been powered on in months; I imagine that charge dwindles with time? Would it be ok by now to let him explore it, or it is a “never really safe” type of thing?
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [February 20, 2023, 6:32pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/2 "2023-02-20T18:32:08Z")
I do not know if a power supply that has not been powered in months is safe. I would err on the side of caution.
Also, I think it may send the wrong message to a seven year old that poking around in some things is fine (safe). Maybe this one is, but the next one may not be and he will have no reason to think he shouldn’t do that.
At some point he can be taught how to safely mess with such things. I am not sure seven is old enough though (I will leave that to others to say).
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### Author:  [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)
#### Post date: [February 20, 2023, 6:37pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/3 "2023-02-20T18:37:32Z")
Do you have kids?
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [February 20, 2023, 6:38pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/4 "2023-02-20T18:38:31Z")
I do not.
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### Author:  [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)
#### Post date: [February 20, 2023, 6:39pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/5 "2023-02-20T18:39:08Z")
Than I’ll wait for someone to actually answer the Factual Question.
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [February 20, 2023, 6:40pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/6 "2023-02-20T18:40:09Z")
Nothing about your question demands a person answering have kids to offer an answer.
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### Author:  [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)
#### Post date: [February 20, 2023, 6:41pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/7 "2023-02-20T18:41:17Z")
Factual Questions does, however, require at least a stab at a factual answer.
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### Author:  [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)
#### Post date: [February 20, 2023, 6:43pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/8 "2023-02-20T18:43:11Z")
Here ya go:
> A charged capacitor left by itself _will_ retain this charge for a long time, even years. -[SOURCE](https://www.plcgurus.net/how-to-discharge-a-capacitor/)
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### Author:  [@Dorjan](https://boards.straightdope.com/u/Dorjan)
#### Post date: [February 20, 2023, 6:50pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/9 "2023-02-20T18:50:32Z")
If you are just taking things apart, leave the PSU internals alone. This goes for adults as well as kids. But explain why to your 7 year old, this is a more useful lesson in electronics for them!
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### Author:  [@Quintas](https://boards.straightdope.com/u/Quintas)
#### Post date: [February 20, 2023, 7:13pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/10 "2023-02-20T19:13:09Z")
> [@Sicks\_Ate](#):
>
> Do you have kids?
He used to, but he let them dig around inside an old PSU a few years back.
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### Author:  [@Folly](https://boards.straightdope.com/u/Folly)
#### Post date: [February 20, 2023, 7:32pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/11 "2023-02-20T19:32:30Z")
A well designed PSU will have bleeder resistors to drain residual charges from capacitors after some number of minutes.
There’s no way to tell if you have a well designed PSU without taking it apart and poking around inside so best to err on the side of no way.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [February 20, 2023, 7:52pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/12 "2023-02-20T19:52:55Z")
> [@Sicks\_Ate](#):
>
> Do you have kids?
> [@Sicks\_Ate](#):
>
> Than I’ll wait for someone to actually answer the Factual Question.
> [@Sicks\_Ate](#):
>
> Factual Questions does, however, require at least a stab at a factual answer.
@Whack-a-Mole did take a stab at a factual answer. If you aren’t willing to accept answers on the grounds of completely irrelevant matters like whether the answerer has children, then I don’t see the need for this thread.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [February 20, 2023, 7:53pm UTC](https://boards.straightdope.com/t/is-an-old-pc-psu-safe-to-mess-with/980097/13 "2023-02-20T19:53:00Z")