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gunrunnerjohn posted:

Make sure the power pack is a regulated 4.5 volts.  The easy way to do this if you're "rolling your own" is to use a 5V cell phone charger or similar regulated wall wart and include a series silicon diode to drop the voltage down to 4.4-4.5 volts.

Early on in my Miller sign life, I've ruined 2 or 3 signs by NOT using a regulated wall transformer.  in fact, it was Miller's own transformer: his first one, not his more recent versions.  I talked with him and he told me that his was not regulated (again, his first version is what I'm talking about) and that I should get a regulated one.  I did and have not ruined a sign since, spanning maybe 8 years or so.

I have asked this question before and have yet to get an answer: I bought 3 transformers at a flea market, each 4.5V, but don't know how to tell if they are regulated or not since there was no directions included.  Is there something on the transformer's case that means "regulated" without actually using that word???  I have 4 Radio Shack transformers and all of them have, on the BOX, the word "regulated" but only one has it actually on the transformer case itself.

- walt

gunrunnerjohn posted:

Your voltmeter tells all.  If you measure the voltage open-circuit from the power supply and it's anything significantly higher than the "rated" voltage, I wouldn't trust it.  Most of the cellphone chargers or USB chargers I check are very close to their rated voltage.

Not sure if you were responding to me or an earlier reply john.  I know this from experience: I HAVE used my meter to measure the output from the old Miller power supply and it was close to 4.5V - a bit over but close enough.  However, since according to Chris, it wasn't "regulated" it allowed spikes (if that's the right word) to slide on thru, which overwhelmed the electronics in his signs.

So IMO, it takes KNOWING for sure, SOMEHOW, that the thing is regulated.

- walt

mike g. posted:

Hi there everyone, Just wondering if anybody knows if you can hard wire the miller signs that come with the AAA battery pack?

I dug out this photo from a previous thread showing additional alternatives:

power alternatives for miller signs - Copy

If you can't readily find a 4.5V regulated wall-wart, you can use a higher voltage DC adapter (9V, 12V, whatever) that you more likely have lying around.  It can be regulated or un-regulated.  Then you use a $1 (free-shipping from Asia) DC-to-DC voltage regulator module set to 4.5V DC.  Note in the left photo there are adapter plugs that convert from the typical coaxial-barrel connector to screw-terminal if you don't want to splice into the wall-wart cable.

Some guys don't have a "free" wall outlet and would rather hard-wire the Miller signs to their train transformer's 14V AC Accessory output.  This way they can turn the signs on/off along with their other accessories.  In that case you can use an AC-to-DC voltage regulator module as shown on the right.  These are about $3 (free-shipping from Asia).

And for measuring/setting the output voltage of these modules...and/or confirming the voltage coming from a wall-wart...you don't need a fancy meter.  If you're near a Harbor Freight Tools store their "Free with Coupon" multi-meter is quite adequate for the job; it even comes battery-included.  I saw a coupon in last Sunday's paper.

ogr hf meter measuring ps1 smoke motor - Copy

 

 

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  • power alternatives for miller signs - Copy
  • ogr hf meter measuring ps1 smoke motor - Copy
walt rapp posted:
gunrunnerjohn posted:

Your voltmeter tells all.  If you measure the voltage open-circuit from the power supply and it's anything significantly higher than the "rated" voltage, I wouldn't trust it.  Most of the cellphone chargers or USB chargers I check are very close to their rated voltage.

Not sure if you were responding to me or an earlier reply john.  I know this from experience: I HAVE used my meter to measure the output from the old Miller power supply and it was close to 4.5V - a bit over but close enough.  However, since according to Chris, it wasn't "regulated" it allowed spikes (if that's the right word) to slide on thru, which overwhelmed the electronics in his signs.

So IMO, it takes KNOWING for sure, SOMEHOW, that the thing is regulated.

- walt

If it's reading 4.5VDC with no load, I have to believe it's regulated.  Very tough to believe they make such a deal of the 4.5V and then would supply unregulated DC voltage from their own power source that would exceed that figure.  As you previously stated, Miller used to have an unregulated one that toasted some signs, right, now they supply a correct one.

gunrunnerjohn posted:

As you previously stated, Miller used to have an unregulated one that toasted some signs, right, now they supply a correct one.

Yep, that's what I've been trying, not too well though, to say.  The first one that he sold was not a regulated one, unfortunately for me and 3 of my signs!

So I still ask, is there any way to tell by looking at some keyword, or something, on the wall wort?

- walt

Last edited by walt rapp
walt rapp posted:
gunrunnerjohn posted:

As you previously stated, Miller used to have an unregulated one that toasted some signs, right, now they supply a correct one.

Yep, that's what I've been trying, not too well though, to say.  The first one that he sold was not a regulated one, unfortunately for me and 3 of my signs!

So I still ask, is there any way to tell by looking at some keyword, or something, on the wall wort?

- walt

Not really.  Some will be specific, others won't.  The only way I can tell is with a bench supply and then adding a load to the supply.  I will say that virtually all of the ones that are intended to recharge phones are regulated supplies and should deliver close to their nameplate ratings.  If you measure the output voltage with no load and it's at or very near the nameplate voltage, it's almost always a regulated supply.  The unregulated ones typically are 50% or even more over the rating with no load.

And a very crude way to identify regulated and unregulated is by size and weight. USUALLY (and I say it guardedly) unregulated is heavy and bulky because of transformer.  The regulated tend to be lightweight and small sized.

But you best safest way is as GRJ says put a load on and watch the meter it its rock steady, its regulated.

Thanks guys for the input. 

As I mentioned up above, I put a meter on the first edition Miller power supply transformer and it was something like 4.7V - but Chris himself said that his first edition power supply was UNregulated.  I tried measuring under load and it was still OK.  Chris said that a spike probably occurred causing the over-voltage situation and suggested I get a regulated one, which according to Chris, would prevent the surge.

I know that since I have since used regulated transformers on all 11 of the signs that I have that NONE of them have had a problem since.

Maybe I'll just toss the 5 transformers that I bought at a flea market instead of taking a chance.

thanks again - walt

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