Why Wait 10 Seconds Before Rebooting Your Router

[Indianatone]

The CRT cannot store voltage, but their is a connection on the side of the CRT (a thick wire) that comes from the flyback transformer which could give you a severe zap.

YOU ARE VERY WRONG. The CRT does store a high charge of up to 30KV for days.

 

[LMiller7]

Regarding the handling of CRTs:
This is not something that an amateur should even consider. It should only be done by someone with the proper training and experience. I won't go into any details because at the end all you would have is a little knowledge. And as the saying goes, a little knowledge is a dangerous thing.

Over the years I have replaced many CRTs so can speak from experience.

 

[PaulGo]

After doing some research I will agree that a CRT can store voltage. I wlways grounded the flyback connection to the CRT before I handled it so both the flyback and now I know CRT did not have any voltage. Working on broadcast monitors I once got zapped by putting my hand to close the the HV while it was on.

 

[lehnerus2000]

After doing some research I will agree that a CRT can store voltage.

Maybe you should amend/edit post #19.

 

[Britton30]

Water bath. Will have to be dried throughly afterwards (2 big fans, left overnight), and you need to check that there aren't water-sensitive components first, but that's how I inspect PSUs.

Other general advice is wearing rubber boots and use a single arm (and doing this with a friend). This will prevent the current from going through your arms or discharge through your feet (passing through the heart in the process), and the friend will be there to rescue you in case of electrocution (knowing Basic Life Support procedures would be optimal for both, any first aid manual has them, if you saw at least one episode of Baywatch you should know them as well). They call it "the buddy system". Never do something dangerous alone. Remember the movies.
If you get a discharge with this setup it will be painful and you may lose sensitivity/movement of the finger/hand for a few minutes. Better than dying anyway.

I don't use rubber gloves as I drop enough stuff already, with gloves I'm less precise than a 90-year old with parkinson.

You advocate dropping a CRT and PSU into water to discharge them? I wish you luck with that method.

 

[PaulGo]

After doing some research I will agree that a CRT can store voltage.

Maybe you should amend/edit post #19.

Done.

 

[Britton30]

When I've called my ISP (Comcast/Xfinity) they always tell me to turn off everything for 2 minutes. I've got ahead of that, I turn it all of before I call.
"Mr Britton I don't see your modem"
"It's off because you always want me to turn it off no matter what the issue."
"Turn them back on please."

 

[oneskrewluse]

When I've called my ISP (Comcast/Xfinity) they always tell me to turn off everything for 2 minutes. I've got ahead of that, I turn it all of before I call.
"Mr Britton I don't see your modem"
"It's off because you always want me to turn it off no matter what the issue."
"Turn them back on please."

^^^^my hero <(0.0)> ^^^^

 

[lehnerus2000]

After doing some research I will agree that a CRT can store voltage.

Maybe you should amend/edit post #19.

Done.

 

[bobafetthotmail]

You advocate dropping a CRT and PSU into water to discharge them? I wish you luck with that method.

No, I just said I gently drop PSUs in water (in an iron container on the grass outside) before disassembling them to see if there is something fixable (usually to change the fan). You have a better idea? I cannot reach the capacitor's contacts in any way before it's fully disassembled and I'm not going to take risks. I'd rather risk damaging the PSU than myself. I can guarantee that it does no damage to PSUs (if you take the time to dry it well with fans before assembling it again and powering up).

I don't know about CRT, but I suggested it because in case you cannot reach the contacts due to casing or whatever making the disassembly at risk of electrocution, water could be a solution.

 

[Britton30]

You advocate dropping a CRT and PSU into water to discharge them? I wish you luck with that method.

No, I just said I gently drop PSUs in water (in an iron container on the grass outside) before disassembling them to see if there is something fixable (usually to change the fan). You have a better idea? I cannot reach the capacitor's contacts in any way before it's fully disassembled and I'm not going to take risks. I'd rather risk damaging the PSU than myself. I can guarantee that it does no damage to PSUs (if you take the time to dry it well with fans before assembling it again and powering up).

I don't know about CRT, but I suggested it because in case you cannot reach the contacts due to casing or whatever making the disassembly at risk of electrocution, water could be a solution.

Well maybe Italian electricity is different than the US kind. Ours can kill if electronic components are put in water. That is very reckless and dangerous to tell people to put a PSU or CRT in water to discharge it. If the item was good before I'm sure a water bath will destroy it. There are also proper ways to discharge capacitors, Google is your friend.

A better idea? How about a volt meter?

Are there any other folks who test PSUs in a water bath?!?

 

[bobafetthotmail]

Ours can kill if electronic components are put in water.

Only in specific conditions. Electricity takes the shortest path to the ground, or in the case of a capacitor the shortest path to the other contact.
As long as you are not in the water, the container is metallic and on the ground outside (not inside a house, needs to touch soil to discharge anything to the ground, although for capacitors it's not a major requirement as they just need to short the contacts), the risk is comparable to shorting a capacitor with a screwdriver. Then use the average shovel with a wooden/plastic handle to drop the unit in the water from safe distance.

And of course it's not connected to the wall plug. I need to discharge capacitors, not kill every component in it with wall plug power.

If the item was good before I'm sure a water bath will destroy it.

Afaik, as long as it didn't contain serious speakers or a battery, and it is dried thoroughly afterwards, it will be fine. It's salt water that nukes everything after even a few hours of exposure.

Me and other techs of the shop did work on so many MP3 players and cellphones/smartphones that were given a ride in a washing machine (left in dirty clothing, washed with it, careless owners I guess) that I do know a bit about this.
I don't claim 100% survivability, but still high enough to make it worth the effort.

And anyway, this treatment is reserved for PSUs that have failed somehow or stuff that cannot be operated on otherwise and would have to be trashed, so the risk is acceptable.

There are also proper ways to discharge capacitors, Google is your friend.

No duh! I know that screwdrivers work, the point is that depending on how the device is assembled, there could be no way to do so without tearing down everything which takes a relatively long time, compounding the risk (the more time it takes, the higher the chance I will screw up and get a jolt). For example with the average PSU I would need to unscrew the case's screws, and then I have a ton of electronics exposed while I am removing the circuit board to get at the capacitor's contacts that are below it.

That can be the case for any device not meant to be serviced.

Are there any other folks who test PSUs in a water bath?!?

As I said, the water bath is just to discharge capacitors I cannot reach easily, before I open the thing up and attempt repairs.
I have a semi-professional if a bit makeshift setup to test the PSU voltages at various loads for PSU testing.

 

[Indianatone]

The capacitors in question have a charge of between 200 volts direct current(120V AC input) and 350VDC (240V AC input) and there is no way in hell you should be dunking charged power supplies in water. If there is a charge it will blow the PSU to pieces finding the quickest way to ground by everything being shorted together. I have worked on many a switch mode power supply and the way to discharge them is a bleed resistor (100K ohms) across the terminals of the capacitors. Many quality supplies have this but cheap and nasty ones do not. Any water other than distilled contains impunities which will corrode the circuitry. Also remember this is mains voltage and if the PSU is malfunctioning it will destroy what it is hooked to. Could be your pride and joy.
In any case why even bother. Power supplies are relatively inexpensive and replacement is the safest option. No user servicable parts inside means exactly that and a technician is really not able to fix the units properly unless an electrolytic capacitor on the secondary side is bulging. If the primary side has failed forget it.
The worst or best SMPS I worked on was for a Sony professional multi standard VCR. The input voltage was 90V AC to 250V AC and it had a voltage doubler so the UK mains supply was rectified to 350v DC and then doubled to almost 700V DC before the switching circuitry created the stabilised DC supplies. Talk about treating something with respect. Oh and I could not order a new supply as a Sony agent we had to repair the unit to component level. The thing was so stable you could record or playback a tape and wind the voltage up and down through a variac and it had no effect on the recording or the playback.
I personally would recommend anyone reading this if they suspect they have a bad power supply just replace it, fooling with it could be the last thing you do and you will wake up dead.

 

[bobafetthotmail]

If there is a charge it will blow the PSU to pieces finding the quickest way to ground by everything being shorted together.

Did you actually try? At most I got some popping like with using a screwdriver.
And all PSU that "blew up" (on the testing table when pushed at more than 50% of their rated output, no water involved) didn't even dent the case.

You want to see a video of a joker that risked his own life to do something terribly stupid yet not as spectacular as expected? He drops buckets of water on a bunch of live PSUs, yes, they are powered. This is the video.

There are others.

Any water other than distilled contains impunities which will corrode the circuitry.

Not for a few minutes. There is a decent chance of saving stuff that was for hours in a clothing washer machine so go figure.
If it was dropped in the sea then it's dead. The salt kills.

o user servicable parts inside means exactly that and a technician is really not able to fix the units properly unless an electrolytic capacitor on the secondary side is bulging.

Quite a few cheap units use a fuse as a power surge protection. Yeah right, you heard it correctly. Power lines get jumpy due to something, power surge fuse blows, and I have to trash a technically still operational PSU.

And of course the fans start sounding like a drill or break outright, and for a few bucks worth of fan (actually less as we have a ton of cannibalized components in storage) I have to trash a PSU.

 

[Indianatone]

If the fans need replaced fine, the power supply is working then there should not be an issue with the capacitors retaining a high voltage charge. The issues with a high voltage charge is usually when the power supply is electronically faulty. I was always taught electricity and water do not mix and I keep it that way. You can do what you wish but if you are servicing other peoples property what you are doing with water may not be the correct course of action. What I would do for myself is not what I would do in a business service environment.

 

[bobafetthotmail]

Customers always get stuff that is used but tested (or new or even premium if they pay more for it), so we just swap the PSU with a working one and tell him/her it's fixed. It's not like we don't have a ton of cheap PSUs around, and a quick fix is better PR anyway.

Since we are also required by law to get faulty equipment back (as we and the shops selling electronic equipment are responsible for proper disposal of such stuff), we get it, and try to fix it. If it gets fixed we test it and if it passes the test it is added to the bunch of used components available.
If not, it ends up where it was headed for in the first place. Recycling plants or landfills.

Our profit margins weren't huge even before the crisis and whatnot, and this is one of the tricks we do to still turn a profit.

 

[cyclic]

we just swap the PSU with a working one and tell him/her it's fixed

Perhaps not for you, in the UK admitting to such would see you closed down by officials. I won't bore peeps with the number of illegalities, but there are a number. Surely honesty would say to tell the customer the unit is more cheaply replaced than fixed?
The unit works, no need to obscure the facts. all customers are not dim!

 

[bobafetthotmail]

If you factor the man-hours used to fix the unit (and that there is no way to know if it is fixable before wasting time on it), it's far more cheaply replaced. The fixing happens in downtimes (time when the tech would be doing nothing anyway)

They just have the choice between ultra-cheap (used/fixed but tested), buy a new crappy PSU, or quality PSU. What they choose we do.

 

[Britton30]

Why the hell all the PSU discussion? The thread is about rebooting a router.

 

[Layback Bear]

Let me see if I understand this correctly.
If I want to reboot a router I have to stand in wet grass or on a metal ladder with a metal bucket full of water and then pour it on hardware with hight voltage.
All these years I just unplugged it and/or held in the reset button.
I guess that is why I'm not a expert working in a computer shop.