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? on installing decoders in both a and b units

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  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 12,212 posts
Posted by wjstix on Monday, September 29, 2008 7:25 PM
KIM it's the same chassis in both engines, so you could switch the body shells later if you wanted to.
Stix
  • Member since
    March 2004
  • From: Central Texas
  • 251 posts
Posted by novicerr on Monday, September 29, 2008 10:05 AM

Thanks wj. Tonys trains sent me the QSI revolution for the a unit and a NCE decoder for the b unit. I considered putting the sound decoder in the b unit, but being such a novice I decided not to. I have both decoders installed. Havent installed the speaker yet ( ran out of time yesterday). Will get it installed today I hope. Installation was pretty straight forward. Remove the old circuit boards from the a unit and hook up the sound decoder. (making sure the decoder is orientated the right way, front towards front and not upside down. Dont ask how I know). I havent tried matching speeds yet since it was so late. Hope I can get them to match. Will keep you informed. I might make a railroader yet LOL.

Thanks to all for the help.

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 12,212 posts
Posted by wjstix on Monday, September 29, 2008 8:30 AM
FWIW in an A-B situation I like to put the sound decoder in the B unit, as it has more room inside for a larger speaker and enclosure than the A unit does.
Stix
  • Member since
    October 2004
  • From: Colorful Colorado
  • 8,639 posts
Posted by Texas Zepher on Saturday, September 27, 2008 1:09 PM

 novicerr wrote:
my pcm units have 6 wires running between them. These units are not sound equiped right now. ... I do plan on using the wires for the speaker, which I am installing in the b unit. Will probably go ahead and install a decoder in the b unit also, just in case I have too much current for the QSI revolution in the a unit. Hope this makes sense to you.
Yes makes sense.  Just make certain the decoder choosen for the B unit can be configured to match the speed curves of the QSI.  Otherwise you could end up with the units fighting each other instead of helping. I had a friend with an ABBA unit that he couldn't figure out why they wouldn't pull very much.  Come to find out one of the B units had a different brand of decoder so it was running at a totally different speed.  It was just spinning its wheels while the others drug it around like dead weight.

FYI - I got a note from PCM concerning the pins on the wiring harness for a decoder and sound equipped unit.   I would recommend you use the harness in the same way (because personally I would have done it different)  Here is the core of that e-mail:

 PCM-BLI tech support wrote:
The B unit has a motor and speakers, but is designed to be a slave
to the decoder in the A unit. In the six wire tether:

Motor
Motor
Speaker
Speaker
Track
Track

You'll need to test it to know which motor wire goes to which side of the
motor - I'm not positive.

 

  • Member since
    March 2004
  • From: Central Texas
  • 251 posts
Posted by novicerr on Saturday, September 27, 2008 12:52 PM

Yes Texas Z, my pcm units have 6 wires running between them. These units are not sound equiped right now. They were bought from FDT on sale a couple of weeks ago. The sound/dcc equiped were sold out. I do plan on using the wires for the speaker, which I am installing in the b unit. Will probably go ahead and install a decoder in the b unit also, just in case I have too much current for the QSI revolution in the a unit. Hope this makes sense to you.

 

  • Member since
    October 2004
  • From: Colorful Colorado
  • 8,639 posts
Posted by Texas Zepher on Saturday, September 27, 2008 11:03 AM
 novicerr wrote:
My pcm f3A and B units are both powered. (DC). I am installing a QSI sound decoder in the A unit. Should I install a seperate decoder in the B unit or use one decoder?
Normally I'm a one decoder per unit person BUT - My PCM units have 6 wires running between them.  Do yours?   From the factory, the sound equipped units had a sound decoder in the A unit with the speaker in the B unit.   If those wires and plugs are already there I would use them.
  • Member since
    March 2004
  • From: Central Texas
  • 251 posts
Posted by novicerr on Saturday, September 27, 2008 4:55 AM
Thanks for the reply. Was pretty sure two decoders was the way to go. Will do it that way.
  • Member since
    May 2002
  • From: Massachusetts
  • 2,807 posts
Posted by Paul3 on Friday, September 26, 2008 9:18 PM

I would use one decoder per motor as a general rule of thumb.  You could try using two motors for one decoder, but you may blow the decoder if you exceed the amp rating.  Considering we're talking about a $100 decoder, I wouldn't advise it.  Just get a simple DH123-type decoder for $20 for the B-unit, and put the QSI in the A.  Or, you could just put the QSI in the B and the cheap decoder in the A.

Paul A. Cutler III
************
Weather Or No Go New Haven
************

  • Member since
    March 2004
  • From: Central Texas
  • 251 posts
? on installing decoders in both a and b units
Posted by novicerr on Friday, September 26, 2008 7:46 PM

My pcm f3A and B units are both powered. (DC). I am installing a QSI sound decoder in the A unit. Should I install a seperate decoder in the B unit or use one decoder? Think I read somewhere to install seperate but not for sure if I did. Looks like I will be mounting the speaker in the B unit since it has a little more room for it.

Thanks in advance

Charlie

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