Model Rect Corp Railpower 1370 Design Flaw

Discussion in 'FAQs' started by zeeglen, Jan 12, 2005.

  1. zeeglen

    zeeglen Member

    Aug 26, 2003
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    There may be a design flaw in current production of Model Rectifier Corporation Railpower 1370 power packs. I'm trying to get to the bottom of this issue and not having much luck.

    I have 2 MRC Railpower 1370 power packs purchased 2 years ago. Both have full wave 120 pps output, same alternate pulse peak voltage at all throttle settings. According to others, the MRC 1300 has the alternating differential pulse voltage, and according to MRC personel i've managed to talk to the 1370 is supposedly the same. Apparently all the MRC power packs have alternate pulse voltage.

    Except for my own 1370's.

    MRC has not been cooperative in discussing this issue. I am trying to find out if this design error has ever been corrected or if current production still has the error. MRC reps that i have been able to talk to do not seem to be aware of this problem, nor have they shown much interest in resolving it.

    The issue:

    The MRC Railpower 1370 pcb PC-1370M-1 16-01-01 has a trace pattern error that connects resistor R1 to the output of the bridge rectifier instead of the input. The resistor R1 was left out during production of this revision of the pcb since it would not have been any use. (a simple fix, if your MRC 1370 is the same all it takes to get much better performance is the addition of a 6.8K resistor...)

    The scope photo shows the difference. The yellow trace is a MRC 1440 operating correctly with alternate pulse voltages. This makes a huge difference in slow speed locomotive performance. The blue trace is my MRC 1370 - no pulse voltage differential - the result of the design error and subsequent production removal of resistor R1.

    See the scope photo from a previous post at message #24 (scroll down)

    Sorry, the gauge software will not let me post the same photo here. One error in the original post - the MRC 1300 does NOT have the design flaw of the 1370. At the time of this previous post i was under the impression that all 1300 series were the same and did not know that the 1370 had a design fault.

    If you are able to determine the output waveform of your MRC Railpower 1370 let me know please if it is correct (as per the yellow 1440 trace) or flawed (as per the blue trace of my own 1370).

    If you own a Model Rectifier Corporation Railpower 1370, MRC can be queried about this at 732-225-6360
  2. docsnavely

    docsnavely Member

    Sep 21, 2004
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    That seems kinda dirty to me!! All they need to do, as you said, is to patch that resistor to the input of the rectfier. I could just imagine what it would look like with the resistor left in place at the output!!! Good luck getting them to admit any error!!:rolleyes: I guess if they just keep giving you the cold shoulder, it'll turn into a case for the BBB.:cry: :thumb: