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Discussion Boards => HO => Topic started by: Sunshine Express on June 09, 2007, 10:02:24 PM

Title: Atlas FP7 Diesel Decoder fitting
Post by: Sunshine Express on June 09, 2007, 10:02:24 PM
I would like to fit a Lenz one function decoder to my Austrian made Atlas FP7,which is in good condition.I have fitted older Athearn Diesels OK but am in need of experienced assistance with this one,by way of any illustrations or instructions. ???
Title: Re: Atlas FP7 Diesel Decoder fitting
Post by: Hunt on June 10, 2007, 01:44:15 AM
It is lacking some particulars; but, possibly this link will help you.
Click http://www.tcsdcc.com/decoderpics/Atlas%20FP7%20older%20style/Atlas%20FP7%20Older%20style.htm (http://www.tcsdcc.com/decoderpics/Atlas%20FP7%20older%20style/Atlas%20FP7%20Older%20style.htm)
Title: Re: Atlas FP7 Diesel Decoder fitting
Post by: Sunshine Express on June 10, 2007, 06:06:10 PM
Hunt  Thank you,very good illustrations,will follow up.
Title: Re: Atlas FP7 Diesel Decoder fitting
Post by: MrMunchkin on June 11, 2007, 06:20:33 PM
I followed these instructions EXACTLY and my loco won't run (it ran fine before on straight DC) I think my decoder might be bad.
Title: Re: Atlas FP7 Diesel Decoder fitting
Post by: Jim Banner on June 11, 2007, 09:20:53 PM
Quote from: MrMunchkin on June 11, 2007, 06:20:33 PM
I followed these instructions EXACTLY and my loco won't run (it ran fine before on straight DC) I think my decoder might be bad.

The lower brush holder in this locomotive is not insulated from the chassis.  So any poorly insulated joint that accidentally touches a chassis component will short the decoder.  If you use lights with one side connected to the chassis, this will short the decoder.  And if you connect anything to the right side of the circuit board except the orange decoder lead, this will short out the decoder.  I am not sure if the trucks have enough freedom to allow a wheel flange touch the locomotive frame in a derailment, but that is another way of shorting out a decoder in Atlas/ROCO locomotives with this particular style of motor.

Unfortunately, not all decoders protect themselves when such shorts occur.  Unprotected decoders can be destroyed even by very brief short circuits.  If your decoder was one of the unprotected ones, there is a good change that it is now bad.

It is only slightly more work to make a washer out of .020 styrene to insulate the bottom brush holder (it should look just like the red one on top of the motor) and then solder the orange decoder wire directly to the brush cap.  This can save a lot of grief on Atlas/ROCO locomtives.

Title: Re: Atlas FP7 Diesel Decoder fitting
Post by: MrMunchkin on June 13, 2007, 08:37:26 AM
Hey, thanks, I'm gonna try that later today.  P.M.