new DCC decoder for Spectrum Heavy Mtn.

[jtbterri]

 I recently committed a big error by leaving my loco in its plastic case on a table in the afternoon So. Cal. sun.  The result was a melt down of the tender shell and the cab on the loco shell .  After removing the tender shell, I found no physical evidence of damage to the PC board or the components.  However, when I put it on my programming track, I could not access the loco with my Digitrax Zephyr system.  When I tried to read the loco address the response wwas dnd, no decoder detected.
I checked the Bachmann online Parts catalog for the 4-8-2 Heavy Mountan and found that the PC Board with decoder was not in stock.  I called the Bachmann Service Dept. and they verified that this part was not available and did not know if it would come back in stock.  Also, no Spectrum Heavy Mountains were available if the loco was returned for service.  I did order a replacement loco and tender shell to repair the cosmetic damage done by the afternoon sun tan.
With the tender shell removed, it appears that the DCC decoder is hard wired to the PC board.  Can this decoder be removed and a new one wired using the existing wires?  If so, has anyone done this and what decoder?
Thanks for any assistance you can provide.  This loco was the pride of my fleet 
George

[Bucksco]

http://www.bachmanntrains.com/home-usa/board/index.php/topic,19982.0.html

[jtbterri]

Thanks for the info.  I forgot to mention that before I tried it on the programming track I tried it on the main.  The Zephyr does not recognize it in either case.
George

[skipgear]

The decoder in the Heavy is just hardwired to the light board. You will find numbers on the light board that refer to the NMRA standard pinouts. The decoder can be replaced with any solder in decoder that will fit the loco. A Digitrax DZ125 or DN135 should fit fine.

[jtbterri]

Thanks!  That's what I hoped!  As soon as the new tender shell arrives I'll get started again!
George

[jtbterri]

Well the new tender shell arrived and I started over again checking out the PC board and DCC Decoder.
After directly connecting the board to the Digitrax Zephyr and placing the loco and tender in a cradle I found that the decoder had not been damaged and that the loco did operate in DCC.  One problem that I had missed was that the slide rods had separated from their guides due to the extreme heat and the guides were somewhat distorted preventing the wheels from turning.  When this was corrected the loco did operate, although very jerky and out of balance at low speed.  Other problems will obviously have to be addressed. 
When I tried to reassemble the tender, I found that another plastic part had been warped.  Between the PC Board and the diecast tender frame there is a plastic "plate" P/N 0AC01 on the parts explosion diagram enclosed with the loco.  This plate has extended guides for the "bars" that carry the power from the trucks to the PC Board and at the same time, allow the truck to rotate thru a limited radius.  With this board warped, the trucks won't rotate and the tender shell no longer fits on top of the tender frame.
I can't find the plastic board #0AC01 listed as an available part, and I'm not supprised.  I do find that the complete USRA Long Tender is available. It says DCC ready but how?  Put the PC Board and Decoder from my damaged tender in the new one?  Any help would be greatly appreciated
George

[skipgear]

Just buy a DCC ready tender, install the decoder and be done with it. The tenders are easy enough and cheap enough that it's not worth all this effort trying to fix the tender you have. You can pick up tenders for well under $20 if you look hard enough.

As far as the running rough, it may be a lost cause. If parts of the valve gear and mechanism, or even the drivers got warm enough to warp then it will never run the way it should.

[jtbterri]

I guess I wasn't clear enough.  The old tender is useless except for the PC Board with the DCC decoder prewired.  My question is, can I buy a new Bachmann DCC ready tender and swap my board with the board in the new tender? 
Also, I agree about the running characteristics.  Too bad because this really is a smooth runner....undamaged!!
Wish I could install a new drive mechanism but too delicate for my old fingers and bifocals!

George

[skipgear]

Yes, the spectrum tender is the same tender that came on your loco so you should have no problems swapping boards.