Athearn PA-1


Trucker-Mike

Trucker-Mike

Member
This just in, an Athearn PA-1 in Southern Pacific Daylight colors. Got seven passenger cars and a PA-1 B unit dummy for a good price, but not so good if the locomotive will not run. (I have removed the two videos associated with this thread. I added a new one at the bottom.

The owner's manual exploded view is below.

Now it's up to you, is it trash? Am I doing something wrong? Can it be mended? You tell me.
 

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As Sherrel has posted check the wheelsets and trucks.

I've had trucks where the bearing wasn't sitting correctly causing a short.

Also check that the arm (I'm not sure what you call it in the US) the metal piece that comes up from the truck isn't bent and sitting too close to the chassis.

EDIT.

Actually I think disconnecting the trucks from the motor and making sure the motor works might be the first place to start, no point in doing anything if the motors dead.
 
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See the link below. It goes over Athearn pa1s

modelrailroadforums.com

Athearn PA Repair Help

I mentioned a while ago in the "What are you buying this month" thread that I purchased a set of daylight cars with an Athearn Alco PA unit with it. The engine has been giving me some trouble. It seems to stutter quite a bit. I have run other locos on my layout and they seem to run fine but this...
modelrailroadforums.com modelrailroadforums.com
 
The iron ring motor draws "a lot" of power. What you're seeing as a short may just be the motor drawing more power than the power pack can put out. It's doubtful, but I'd check to see if the motor runs by itself, as was mentioned above.
The engine will need new motor mounts. That engine is probably 50 years old, and the rubber mounts have almost certainly deteriorated to the point they will crumble to dust if you remove the motor.
On the bottom of the motor you will find a clip with two pointed tabs that are meant to contact the frame. Make sure they are getting good contact.
If there is a short in the engine, isolate it to what is shorting. On an Athearn, they are easy to work on. Remove the motor and place the engine on the track, and turn up the power. If there isn't a short, check to make sure the metal strip that runs across the top of the motor isn't touching anything other than the top contacts of the trucks, the top of the motor, and the tab on the back of the headlight.
 
That looks like a Throttle Pack 501 so if it is then about 1 amp so enough to run a single Athearn engine
since the light works he's getting power from the trucks That's the only way the light will work
There's something with the motor even though he can turn it by hand the motor mount is not right it's loose
He needs to take a few things apart and test one at a time
And no it's not trash old yes but aren't most of us :p
 
That's not a dummy that's been converted It was powered from day one
Now that engine has the old metal side frames with the outside bearings again old but still works
The wheel sets I had to go look at some I still have and the wheel sets all the way adjusted in are perfect gauge

If you have a multi meter remove the trucks then you can test for a short from one side to the other
If none then either the motor has a short it doesn't look like it was run that much so would not think so

Don't know where you are located but harbor freight has cheap meters and work fine for this use

The worm housing will allow the truck t drop out then the cover plate will let the truck come apart but you need to check for a short before taking the truck apart
 
TRAINNUT said:
do the wheels move freely when you move it around?
Click to expand...
Since the gears in the trucks are locked into the worms you can't move the whole thing with the gear units in place on the top of the towers. The plastic housings with the worms can be removed by gently prying them away from the tower.
The main problem as I see it, is the short. I would remove the rear truck and see if you get a short between the frame and the wheels on the front truck. You might remove both trucks and see if you can get the motor to run without them. Try touching one wire to the frame and the other to the contact strip that normally contacts the wipers from the trucks. You might invest in a multimeter that has an ohm function, and see where there is continuity in various places.

Have you checked to see if there is a bearing out of place within the trucks. I don't recall if the bearings are inside wheels or in the sideframes, and right now I can't get at one of mine to look. Also, be sure to check the gaging of the wheels is correct (you need an HO scale NRA gage). It might be possible that the half-axles are touching in the middle of the gear. You can't see that, but if the wheels are in gage, they would not be.

Let us know what you find.
 
Seems like someone said that
" Now that engine has the old metal side frames with the outside bearings again old but still works
The wheel sets I had to go look at some I still have and the wheel sets all the way adjusted in are perfect gauge "

And the half axles cannot touch on this type of truck and the only bearings are the ones pressed into the metal side frame and the ones on the worm
 

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I should have taken pictures of this, but I made a video of the rebuild. Very crude, but it is my first "production" video. Here is a link to YouTube.
Thanks to everyone for their input on this.
Cheers for now,
Trucker-Mike
 
trailrider said:
Since the gears in the trucks are locked into the worms you can't move the whole thing with the gear units in place on the top of the towers. The plastic housings with the worms can be removed by gently prying them away from the tower.
The main problem as I see it, is the short. I would remove the rear truck and see if you get a short between the frame and the wheels on the front truck. You might remove both trucks and see if you can get the motor to run without them. Try touching one wire to the frame and the other to the contact strip that normally contacts the wipers from the trucks. You might invest in a multimeter that has an ohm function, and see where there is continuity in various places.

Have you checked to see if there is a bearing out of place within the trucks. I don't recall if the bearings are inside wheels or in the sideframes, and right now I can't get at one of mine to look. Also, be sure to check the gaging of the wheels is correct (you need an HO scale NRA gage). It might be possible that the half-axles are touching in the middle of the gear. You can't see that, but if the wheels are in gage, they would not be.

Let us know what you find.
Click to expand...
Thanks for the advise, the motor mount was the cause of the problem.
 
MikeGTW said:
Seems like someone said that
" Now that engine has the old metal side frames with the outside bearings again old but still works
The wheel sets I had to go look at some I still have and the wheel sets all the way adjusted in are perfect gauge "

And the half axles cannot touch on this type of truck and the only bearings are the ones pressed into the metal side frame and the ones on the worm
Click to expand...
Thanks.
 
Those old Athearn blue box PA's were pretty good. Before other manufacturers brought out EMD E-7's, I took the bodies from older LifeLike, and stretched the frame from some PA-1's. They still work fine. You did a nice job.
 
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