Author Topic: New install on a bachmann F7  (Read 305 times)


  • Engineer
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  • Posts: 57
  • Kevin W.
New install on a bachmann F7
« on: June 13, 2020, 04:27:37 PM »
I just did a fresh install on a dcc ready loco... the new RP power backup modules are far better than the ka 3... I will be replacing the KA3 on the other loco I have soon... I highly recommend using them and /or replacing the other brand KAs


In my defense, I was left unsupervised....


  • Conductor
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  • Posts: 146
Re: New install on a bachmann F7
« Reply #1 on: June 15, 2020, 11:29:51 PM »
Actually, I have installed KA3s and 4s and operation is excellent on my not-fully-wired NEC layout. I get about 30 seconds run-on power with lights and sound with the KA4, like a battery!


  • Conductor
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  • Posts: 664
Re: New install on a bachmann F7
« Reply #2 on: June 16, 2020, 12:27:08 AM »
The KA-3 and 4 (and for that matter the 1 and 2) are all great.  They do their job and they do it well. 

However, they don't compare to Railpro's PBM-2.  The PBM-2 has circuitry that keeps the output voltage constant when voltage to the module is lost.  This keeps the speed of the locomotive constant and the lights from flickering.  Any other keep alive has an immediate drop in voltage which causes the locomotive to immediately move slower.

At some point I will make a video comparing the operation of the two types of keep alive.  The results are quite dramatic.