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elkido122

join:2011-02-23
Folsom, CA

[Equip] Power adapter for modem

Well I was reading on smallnetbuilder. A lot of people were talking about stability and saying the stock power adapters that come with modems and routers suck and to replace them.. Does it really make any difference and is it nesscessary to do so?? Just curious thanks


elkido122

join:2011-02-23
Folsom, CA
Anyone


NetFixer
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reply to elkido122
said by elkido122:

Well I was reading on smallnetbuilder. A lot of people were talking about stability and saying the stock power adapters that come with modems and routers suck and to replace them.. Does it really make any difference and is it nesscessary to do so?? Just curious thanks

This is a classic case of YMMV. Look at the power specs for the modem/router and then look at the label on the power supply. If the device's power specs are 12v @1.00 amps, and the power supply has that same rating, it would not hurt to purchase a spare power supply rated 12v @ 1.5 amps. The reason being that the factory supply is running at its rated limits, and continuously operating any device at its max rating is never a good idea.
--
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.

When governments fear people, there is liberty. When the people fear the government, there is tyranny.


elkido122

join:2011-02-23
Folsom, CA
Can't seem to find the power specs on the ea6300.. They never seem to provide that .. I wonder if I can find it for the sb6141 I have as well.. Hmm


tshirt
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I'm a fan of letting the MFG be responsible for providing an adequate PSU/wall wart.
And if replacing it get one that meets OR exceeds that spec.
If you don't see the spec listed at their site or on the box ASK them directly (and CC the FCC and CPSC because those specs and safety check are exactly what those agencies REQUIRE and should ENFORCE.


DarkLogix
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Also if you get a replacement a few things to look for
1. the voltage should be the right voltage

2. the amperage rating can be higher (only the needed current will be drawn and adding 50% will just mean the supply will be running cooler) (also noted with laptop supplies, one laptop that shipped with a 200w supply had an issue that the supply would get HOT to the touch, swapping to a 240W unit solved that)

3. look for it to be a regulated supply vs unregulated (an unregulated depends on the device load to bring the voltage into spec but a regulated one will always output the speced voltage.)

I've run into this with BFL as their supplies were unregulated and were 13v 6a but the device needed 12v, they were depending on the load to drop the voltage and many ran into this being an issue as the supply was running at full load 24/7 and replacing that with a 12v 7a regulated unit provided more stable performance.
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mb

join:2000-07-23
Washington, NJ
reply to elkido122
I would trust the product's design engineer, I'm sure that (s)he chose the appropriate power supply for the device. Don't trust everything that you read on smallnetbuilder, here or anywhere else.


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reply to elkido122
said by elkido122:

Can't seem to find the power specs on the ea6300.. They never seem to provide that ..

12v, 3 amp

said by elkido122:

I wonder if I can find it for the sb6141 I have as well.. Hmm

12v, 0.75 amp
--
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.

When governments fear people, there is liberty. When the people fear the government, there is tyranny.


train_wreck

join:2013-10-04
Antioch, TN
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reply to mb
said by mb:

I would trust the product's design engineer, I'm sure that (s)he chose the appropriate power supply for the device. Don't trust everything that you read on smallnetbuilder, here or anywhere else.

he/she may certainly have, but the actual manufacturer is also very worth taking into account, as i've found an extremely wide range of build qualities in power supplies.

check out this

»www.p3international.com/products/p4400.html

not sure how accurate it is, but can definitely be useful in determining if a given PSU is actually delivering what's printed on its side.


owlyn
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Newtown, PA
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reply to elkido122
said by elkido122:

Well I was reading on smallnetbuilder. A lot of people were talking about stability and saying the stock power adapters that come with modems and routers suck and to replace them.. Does it really make any difference and is it nesscessary to do so?? Just curious thanks

Save your money. When is the last time you had an external power supply go bad? For me, never. And that's with dozens, mostly made in China. If it ain't broke, don't fix it.


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said by owlyn:

Save your money. When is the last time you had an external power supply go bad? For me, never. And that's with dozens, mostly made in China. If it ain't broke, don't fix it.

Then you have been lucky. Before I retired, when I fixed PCs and networks to earn a living, power supplies (both internal and external) were one of the most common items to fail (right up there with hard drives, and fans). And I have certainly had quite a few power supplies go belly up on my own equipment (and it was usually original equipment power supplies that were working at or near their rated capacity that failed).

As for "if it ain't broke, don't fix it", I fully agree, but that doesn't mean that having spares is not a good idea. I don't replace light bulbs or batteries when they are still working OK, but I do keep spares on hand (along with HDDs, power supplies, and equipment fans).
--
A well-regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms shall not be infringed.

When governments fear people, there is liberty. When the people fear the government, there is tyranny.


Doctor Olds
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reply to train_wreck
said by train_wreck:

»www.p3international.com/products/p4400.html

not sure how accurate it is, but can definitely be useful in determining if a given PSU is actually delivering what's printed on its side.

The Kill A Watt only measures what the power adapter/supply is consuming from the power company and has no way to record or display what output the power adapter/supply is generating for a attached device.
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Kasoah

join:2013-08-20
reply to elkido122
I've only had one switch power supply fail ever, it was some d-link 8 port switch.
It was 5v and I happened to have a usb to 5v plug from a cd rom drive and it fit right into the switch. Just used an apple usb charger and it has worked fine ever since.

I don't see any need to replace the stock power supplies. Seems like a waste of money/time.


Kasoah

join:2013-08-20
reply to train_wreck
How would you even test that? That will just measure how much AC current it's using at a given time. It all depends on how much how much the device is drawing and the psu won't give any more than that. It won't tell you how much DC current the PSU is giving out either.

The only real way to test would be with an oscilloscope to check the voltage regulation and ripple while using a load tester.


DarkLogix
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said by Kasoah:

How would you even test that? That will just measure how much AC current it's using at a given time. It all depends on how much how much the device is drawing and the psu won't give any more than that. It won't tell you how much DC current the PSU is giving out either.

The only real way to test would be with an oscilloscope to check the voltage regulation and ripple while using a load tester.

Well a kill-o-watt would show how much power is going in, though it won't account for inefficiency of the power supply.

To know the actual output power of the power supply you could use an AMP-meter, but IIRC that would require splicing into the wires coming out of the powersupply to put the meter in series with the load.

Then if the current is equal to or slightly greater than the rated output power of the supply then a slightly more powerful unit would be good.
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Kasoah

join:2013-08-20
Which is why I said it won't tell you how much DC power it's outputting because of the efficiency from AC to DC.

You still need an oscilloscope to check if the ripple is in line.


DarkLogix
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easier to check the output side


Kasoah

join:2013-08-20

1 edit
reply to elkido122
The DC side is the output side. That still has ripple and you would have to check the voltage regulation.


camper
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1 edit
reply to tshirt
said by tshirt:

I'm a fan of letting the MFG be responsible for providing an adequate PSU/wall wart.
And if replacing it get one that meets OR exceeds that spec....

 
+1

Another aspect of the power warts, besides their power capacity, is how well the power warts handle line voltage transients.

If the a/c power drops for a second, does the wall wart (or the modem) have enough power stored up to ride out the drop?

What about more minor transients that are shorter than a one second drop? Some transients are literally a few millisecond blips, yet a wall wart will past that through. If the device is not able to handle that type of power event, then oddities can (and usually do) occur.

Unfortunately, you will not know about this aspect of the wall warts because I've never seen specs on it.....


camper
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Click for full size
For example, this transient occurred a few hours ago here. Transients like this occur several times a day. Worse ones occur less frequently, but they still occur.


DarkLogix
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2 edits
reply to camper
well you use a UPS for transient
I would think most people here would put their Modem and router on a UPS

on this topic anyone know of a SNMP moniterable Multi meter? You know something that could be monitored to get Voltage and current and have a network monitor program log the data?
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camper
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said by DarkLogix:

well you use a UPS for transient

 
You would think that.

But unless you have an online UPS, you will see a transient ("transfer time") when the UPS switches from line power to battery power. Nowadays, those transients typically run in the area of 4 milliseconds, but I've measured as high as 15 milliseconds.

Additionally, I've seen a UPS or two that actually made the transient worse, i.e., the UPS turned a 1 millisecond transient into a four+ millisecond transient because the UPS switched over to battery.

My old wireless access point (Netgear WAG102) was definitely not happy with the 3 millisecond transfer time of my UPS.