Another DCC Question

Hi Chris I have a digitrax Empire Builder. I have found that when I place a DC only loco on the track, occasionally one of the DCC locos will start to crawl. Nick over at Allied Trains in Culver City Ca. where I bought the DCC set and decoders says that is not possible. I think the DC loco has a parasitic short which is screwing up the DCC signal. He wants me to bring the loco's and the DCC system in for testing to make sure that when I was programing I accidentally did not screw something up in DB 150 unit. I could open up the unit and remove the battery, which would reset it back to factory setting when it gets powered up again. This however would void all warranties.

I changed one motor on a MDC shay and 95% of the time nothing goes haywire. If I get a loco crawl I have to reprogram that specific loco. I have to reset it to factory CV's and than reprogram it.

BTY , all decoders are programed for 3 from the package. So it is already functional. Set you cab to 3 to operate it un-programed. Also it is not recommended to run a DC loco very long on a DCC system. It will damage the motor. Good Luck Mike Mueller

I took the DC loco off before I put the DCC on the tracks. According to Atlas the loco is programed to last two digits of the road number. I did it both ways with no luck, (03 and 15)

I took the other engine and switched it over to DCC and it programed right away. No problems at all. I was wondering if there is a short some where and if a short would cause this?

Chris

If you select address 0 on your throttle and set it to 0 speed it should cure the one problem. Most Atlas dual mode engines have a jumper inside to select DC or DCC. The DB150 does not have a battery so you can not change it.

Make sure the throttle set to address 00 is set to 0 on the speed. I suspect your dual function decoder is detecting the analog bias and thinks it it getting plain DC.

Tim. (Go Boilers!)

Chris wrote:

Chris wrote in news:489a4a89$0$29808$ snipped-for-privacy@news.astraweb.com:

One essential thing to note is that the motor must be *completely* isolated from the track pick ups. It should only recieve power through the decoder.

I would try reading back the decoder's address and verify it's set where you think it is. (Zephyr and Super Chief Systems can do this, but not the Empire Builder for some reason.) Then, I'd select that address and move the speed knob up and down until it returns to zero, and try again.

Be sure to check CV19. It should be 0. (This CV handles a form of consisting known as decoder-assisted consisting. Sometimes it gets set accidently or whatnot and weird things happen.)

Puckdropper

I can not figure out how to get the shell off. Never had Atlas Loco's before. Will work on that more tonight.

I have the Empire Builder. The other Atlas Loco (same as the other just different road number works great)

I checked CV19 and it was set to 0

Thank you for your help. Like I said before I will try to get the Loco apart tonight.

Chris

Address 00 is set to 0. The dual mode jumper is set for digital. Like I said in my other post the other engine (I have two of the same just different roads) works great.

Thanks Chris

I already checked that and it is set to 0

Thanks Chris

On the engine that's running on DCC only make sure you set CV29 to _NOT_ operate on analog.

How do you do that? I am just getting use to the digital controls. I know how to get to CV29, but not sure how to check on the analog part.

Thanks Chris

Ok. I think I figured that out. Still did not fix the problem.

I am now trying to figure out how to take the atlas engine apart to check for shorts. I feel however that the decoder is bad.

Chris

I have done everything so far that was suggested and the engine still crawls when I put it on the track. By the way it does not matter what address I use. I took the engine apart to check for shorts and there are none.

Any more ideas?

Chris

It sure could be a bad decoder. Try resetting it to factory defaults and see if that helps. If it still misbehaves, replace it.

One other thing it could be - look up "status editing" if you use digitrax. Your booster may be sending the wrong speed step commands. *

A decoder will allow the motor to crawl if it has a bad output section (H bridge I think). Make sure a reset doesn't work and then request repair or replacement from the manufacture.