Author Topic: Atlas problems  (Read 308 times)

nortoneye

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Atlas problems
« on: December 24, 2020, 01:02:34 PM »
Good Day all,

Installing RP in an older Atlas F7A.  When LM is plugged in, the LM is recognized, when I apply throttle to it, it moves a fraction of an inch and then the connection indicator goes red and I cannot make connection without removing track power and starting again only to have the same thing happen.  The LM functions fine in another locomotive.  Trying to set the motor current level does not work.  Is the original Atlas motor taking too much current?  I bench tested the motor prior to installing it with an MRC transformer and it worked fine. 

Any ideas?

Thanks and happy holidays!

Jim

Alan

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Re: Atlas problems
« Reply #1 on: December 24, 2020, 02:07:57 PM »
Look for poor connection(s) somewhere between the LM plug and the wheel wipers including the wipers themselves. I suspect you will find a wire hanging on by a strand.
Alan

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When I was a kid... no wait, I still do that. HO, 28x32, double deck, 1969, RailPro

G8B4Life

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Re: Atlas problems
« Reply #2 on: December 25, 2020, 08:10:53 AM »
I agree with Alan, first check the wiring. Loosing radio connectivity is a symptom of loosing power to the LM (or seriously bad RFI disrupting communications but that would be a very, very, very long shot); the motor consuming too much current would trip an over-current warning on the hand held, it should not make it loose connectivity.

Now, when you say

Quote
I cannot make connection without removing track power and starting again

that is a bit odd. When it happens can you jiggle the wires to see if it makes connection again without cycling the power?

I'm presuming this is a hardwire install and your not using an adapter harness on the original motherboard?

Edit: Just looking around, Atlas doesn't make an F7A. They did make an FP7 (two mechanism versions) which don't have motherboards as we known them today but just a plain circuit board as shown in the diagrams below so the hardwire question of mine is redundant.

https://hoseeker.net/assemblyexplosionAtlas/atlasemdfp7diagram1975.jpg

https://hoseeker.net/assemblyexplosionAtlas/Assembly%20Explosion%20Atlas%20FP7.jpg

- Tim
« Last Edit: December 25, 2020, 08:23:51 AM by G8B4Life »

nortoneye

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Re: Atlas problems
« Reply #3 on: December 25, 2020, 09:30:48 AM »
Tim,

The FP7 (sorry for confusion) in the second diagram is the one I have.  Feeder wires come from from both sides on both trucks, I used only one side for track power-perhaps I need to wire in both sides? 

G8B4Life

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Re: Atlas problems
« Reply #4 on: December 25, 2020, 09:59:56 AM »
I used only one side for track power-perhaps I need to wire in both sides? 

Uhh, if you only wired in one side (eg, just the truck wires on the left side of the loco) how are you not getting a short?, or track power at all? did you mean you only wired the LM to one truck? or to one side (opposite sides) of each truck? Clarification needed. In any event it's best to wire in all pickups available, which is both sides of each truck. Not doing so is inviting more trouble than you are saving by not doing it; one dodgy wire or solder joint to a truck and you can easily loose power.

Something else I would check, I imagine that big chassis is diecast metal so make sure nothing electrical can touch it, including any live parts of the trucks and loose (bare) wires. I imagine that the motor is not isolated from the chassis unless you've done this yourself.

- Tim
« Last Edit: December 25, 2020, 10:01:49 AM by G8B4Life »

nortoneye

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Re: Atlas problems
« Reply #5 on: December 25, 2020, 10:10:49 AM »
Yes,  I only used one wire from each truck for the power leads (opposite sides of course)  I did insulate the motor from the frame but there is a mounting screw that I am suspicious of now that I think of it.  I'll check that and wire in both sides of the trucks to the proper sides.  Thanks for the advice guys.  I'll post an update after done

nortoneye

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Re: Atlas problems
« Reply #6 on: December 25, 2020, 07:21:54 PM »
after careful review, i found some binding in he drive gearing and was able to resolve the intermittent loss of power-life is good