All, Thanks for the information posted on OGR.  It’s very helpful.

 I need some help or at least guidance.

 I have a Santa Fe AC6000 6-28339 with a problem, shorting out when power is applied.  I found anytime power was applied to the RAILSOUNDS LITE / DIESEL / LEGACY AC-6000  P/N 691RSL1018 board the engine would short out.  I removed all wires leaving this board and isolated the power input cable.  When I remove the power to this card, the lights and smoke unit actually start to work.

 The bad news is I have to contact Lionel to get a replacement board for $79.00 plus shipping.

 When I looked at the board, there is a black surface mounted component next to the power cable connection that has a crack in the top.  It is a little less than a ¼” square.  There is a number on the component of 104, but I could not gain any more information.

 My question is, what is this component and can I replace it myself?  I do have a surface mount devise (SMD) rework station. Are there failed boards that I can get and remove working components from?

 The other question I need to address is what caused this to fail and make sure any other failed components are replaced, etc.  I would not want it to fail again given the price of this board.

 Any guidance or suggestions?



Dave G.

Original Post
The part is the HD04-T Bridge Rectifier.  The usual reason for those to go is someone connects the chuff switch or perhaps a speaker lead, to frame ground.  On those boards, NOTHING is referenced to frame ground.
Of course, some other failure could have also caused it to die, no way for me to know.
It's an easy part to replace, no special equipment needed, I've done a lot smaller parts with just my Hakko soldering iron.


Received bridge rectifiers (I ordered some spares) from Digi Key.  Checked wire leads to and from the failed board and none reference ground .  Installed the new rectifier.  Not my best work (I should have had the temperature set a little higher to loosen the original solder.).  Tested the engine and it worked in conventional mode!

I'll check the other modes (Legacy) when I get a new set of board to board mating pins for the piggy back communications board.  The originals pins were loose and when I removed the small board, they broke off.

This is all good news as the engine would just short out before replacing the bridge rectifier.

More later.

Dave G.

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