kony <spam@spam.com> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> kony <spam@spam.com> wrote
>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>> kony <spam@spam.com> wrote
>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>>>> Noozer <dont.spam@me.here> wrote

>>>>>>> If I have an external phone modem that uses a 1amp 9vDC tranformer,

>>>>>> That would be unusual.

>>>>> True, but if it is really 9VDC, next is to determine how much current it
>>>>> uses (if there's a multimeter handy) or the more conservative (higher)
>>>>> equipment current rating, or the overly conservative and probably less
>>>>> useful original PSU (wall wart?) current rating.

>>>>> I seriously doubt it comes remotely close to 1A,

>>>> Plenty of mine are of that order.

>>> The wart might be, but I doubt the modem itself is.

>> Plenty were, most obviously those that came in an
>> extruded aluminum sleeve and got quite hot anyway.

> Quite hot and overheated are not the same thing.

Never ever said it was. It is a reasonable indication that
it might well be using something of the order of 9W tho.

>>> If it used 1A @ 9V, that's of course 9W (practically
>>> all heat generated internally), and nothing gets that
>>> hot to the touch or needs significant heatsinking.

>> Which is why quite a few of them came in an extruded
>> aluminum sleeve and got quite hot anyway.

> See above.

See above.

> That is no proof of any particular heat density

It is a reasonable indication that it might well
be using something of the order of 9W tho.

>>> Measure, it's the only way.

>> I doubt too many would bother to supply a
>> 1A wall wart if the modem only needs 250mA

> Whether the figures is close to 250mA or not,
> we can assume the supply current is rated
> higher than the device by a reasonable margin.

Bet its nothing like that sort of margin.

>>> It is not typical for a wart to be spec'd for 100% duty,
>>> very doubtful the modem uses much over 500mA if that.

>> You dont know that his is a modern modem.

> ... and you don't know it isn't, but we both know it had a 1A
> supply and that supplies are always rated higher than the load.

I doubt too many would bother to supply a
1A wall wart if the modem only needs 250mA

> We don't have to guess about it though, a measurement can be made.

I doubt too many would bother to supply a
1A wall wart if the modem only needs 250mA

>>>>> Anyway, the easiest thing to to here is probably put an LM7809
>>>>> linear regulator between the 12V PSU rail and the modem.

>>>> Makes a lot more sense to keep using an external wall wart instead.

>>> If he's keeping the modem external, yes.

>> Even more pointless making an external
>> modem internal unless its very unique.

> There is something to be said for not
> having extra boxes and wires everywhere.

But nothing to be said for mounting and external modem internally.

> Only the OP can decide if this or something else is important, subjectively.

Never ever could bullshit its way out of a wet paper bag.

>>> If not, it depends on how much work he's willing to put
>>> into it as a wart is easier to source but more expensive
>>> to replace than adding a 30 cent linear regulator.

>> You arent comparing apples and apples.
>> It would cost peanuts to repair a wall wart.

> Since I have, I can describe it.

Whoopy fucking do, you might not actually be alone on that, child.

>>> Switch mode wart has higher failure rate

>> Wrong.

> Right

Wrong.

> I have 30+ year old unregulated warts that work fine still.
> It's quite rare to find a switcher that lasts 20 years,

Only because they werent at all common then.

> and I happen to have one in front of me at the moment
> that lasted less than 5 (3.3V, 5A from a 24 port hub).

The technical term for that is 'pathetically inadequate sample'

>>> It may look ghetto to have a cord wedged, running
>>> into the case from outside to get the power in.

>> Why would anyone be stupid enough to mount
>> an external modem inside the PC case ?

> Why would anyone be stupid enough to keep posting about hardware
> when it makes them upset enough to rant about clowns and bags and
> suggestions to have fun as if we needed that invitation?

Never ever could bullshit its way out of a wet paper bag.

>>> There is already an (after dropped) acceptible power source inside.

>> There are hordes of wall warts available.

> Yes, but since this was to go inside a computer case,

You dont know that.

> were you suggesting the OP install an AC
> outlet in there for the wart? Of course not.

Never ever could bullshit its way out of a wet paper bag.

>>> It's really a matter of time, esthetically use of the internal supply is better,

>> Nope, which is why external modems come with wall warts.

>>> but takes longer to implement. If he happened to have
>>> a molex plug, a suitable linear regulator and an idea
>>> for securing it all, it would be a pretty quick job,

>> Bullshit on the mechanicals.

> You're right, it should've been "socket", not plug.

Never ever could bullshit its way out of a wet paper bag.