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Power Pack with no DC current

Started by squibbys, January 07, 2015, 01:02:41 PM

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squibbys

I tested my replacement and it is throwing ac voltage out of the labeled dc terminals directly on the power pack.  Is this normal?

ACY

This is all very bizarre. I have never experienced anything like this. Do you have any working power packs or do you have previous model railroading experience in which you successfully set up and could run trains?

Jerrys HO

I am going to play confused also.
By chance are you reading/using  the meter correctly? Another way to check is to take a bulb like a 1056 automotive bulb ( I keep one made up as a test light by soldering wires to the center probe and to the side with alligator clips on the other end and yes Jbrock I own a real test light also)  now take the leads and clip to the dc terminals you should be able to turn the power up on your controller and the bulb will brighten. If goes full bright then OH OH!
Do the same test to the AC side, they may have them marked wrong and if not I would be making another call.

jbrock27

No squib, that's not normal.  How are you telling that the voltage is AC and not DC?  And yes, I am interested in getting this figured out.

Jerry's hand made light is good continuity tester (yes Jerry, I have one as well, just not hand made).  It works to tell you if there is continuity between 2 places but it will not measure anything for you.  Do you know how to solder squib?

And Jerry, why have to play confused, when it comes so naturally :D
Keep Calm and Carry On

Jerrys HO

Wow Jim,did you really have to go there. I am sure they already knew but now it's confirmed.

jward

Quote from: squibbys on January 07, 2015, 05:50:16 PM
I tested my replacement and it is throwing ac voltage out of the labeled dc terminals directly on the power pack.  Is this normal?

how much ac voltage does it show with the speed control turned all the way up? depending on how well filtered the power supply is, there could be some ac ripple to it. on a basic power pack, ac is converted to dc, usually by a bridge rectifier or a couple of diodes. at this point, all that has been done is to turn the negative portion of the ac wave into positive, giving a half ac wave @ 120hz, instead of the full ac wave @ 60hz. filtering, if any, would be accomplished with one or more capacitors wired across the dc terminals of the rectifier. they smooth out the ripple, but probably not completely. depending on the sensitivity setting of your meter, you could possibly read the ripple as very low voltage ac.
Jeffery S Ward Sr
Pittsburgh, PA

jbrock27

squib, I just reread one of your earlier post in which you answered my question about the 2nd pack and see you said you got from a hobby shop, no markings (generic) and it was used but it had labels.  What kind of labeling does it have for the terminals?  Is it possible that the shop owner put his own labels on for the terminals and he got them reversed?  In other words, marked the DC as AC and AC as DC ??
Keep Calm and Carry On

Len

Or possibly a 'generic' AC transformer for the 3-rail folks?

Len
If at first you don't succeed, throw it in the spare parts box.

jbrock27

Gotta watch those shop owners, right Len ;)?
Keep Calm and Carry On

Len

Maybe not the shop owner, but sometimes the people who work there...

Len
If at first you don't succeed, throw it in the spare parts box.

jbrock27

Keep Calm and Carry On

squibbys

The AC runs around 2V and the DC is about half of that (.9V) on the multimeter's AC voltage setting. (hertz = 60)  DC does not give me a reading.  I have dabbled in soldering, but stink at it (not enough practice on expensive parts).  On the second power pack, it looks like it was from the factory.  I am thinking my ability to run a multimeter could be suspect.  Does anyone else think that? LOL. 

For continuity I get a reading of OL ("overload" maybe)

jward

I hope you didn't take a continuity reading with the power pack plugged in. during a continuity checque, the meter supplies battery power to the circuit on the assumption this is the only power the circuit is receiving.
Jeffery S Ward Sr
Pittsburgh, PA

jbrock27

#28
Quote from: squibbys on January 08, 2015, 03:07:58 PM
...I have dabbled in soldering, but stink at it...I am thinking my ability to run a multimeter could be suspect.  Does anyone else think that? LOL.

Ok, then you won't be able to make Jerry's handy, dandy continuity/circuit tester.  
You make a good point.    
Let's test the meter on something we know what the value should be, to determine if it is functioning ok.  Get an alkaline battery you know is good, like a AA.  Set the meter to DC and to measure just above 1.5 Volts (on mine this would be 2).  Put the probes on the ends of the battery and tell us what you get.  If you don't have a AA, tell us what DC battery you have.  
Did you get the meter new or used?  Did it come with instructions to tell you where to put the probes in the meter? Where the dial is, V with straight lines in for the DC measuring, V with the wiggly line is for measuring AC.  The probes go into COM and V to measure voltages, just in case you did not know.
And those are really weird readings you gave us, not normal, fer sure.
Keep Calm and Carry On

squibbys

The 9 volt battery test on my multimeter comes with a dc voltage reading a little over 9.5V.  I suppose this means the power packs are the culprit.  It just seems weird to have two bad power packs in a row.