Need some professional advice

[Mr Mechanic]

I have 2 DCC GP7 HO locos, one with sound and one without. The one without sound has the "transformer hum" and does not have very good low speed operation,to which I have found out is normal. When I have them both connected together the one with sound,at low speed where I run them,just drags the other with it,I can hear the wheels slipping. I had sent the one without sound back to Bachmann to have repaired and was told there is nothing wrong with it. Through some research I have found PC boards that are replacement for the ones in them that are "quiet running and have better low speed operation" Now my question,if I change the board in the one without sound will it fix my problem and will they run a little more equally?

[Hunt]

Your locomotive without sound has the symptoms of a standard Bachmann DCC decoder installed. The Bachmann standard decoder does not support the CVs required to speed match locomotives.  A decoder that is a "quiet running" type should support CVs 2, 5 and 6, which are the CVs required to do basic locomotive speed matching. 

Research DCC speed matching as there are several methods that can be used.

[jward]

have you tried adjusting the speed settings in the decoders so they match one another?

cv2 controls start voltage, and is supported in all Bachmann decoders.
cv5 contros max voltage, this one should be in the sound unit but may not be supported in the non sound one. an aftermarket decoder will most likely support cv5.
cv6 controls mid range voltage. it should be supported similar to cv5.

by using your command station to adjust these values you should be able to speed match these locomotives. what dcc system are you using? can it program decoders?

[Mr Mechanic]

I am new to DCC so most of the terminology I don't understand. I am using a Bachmann E-Z Command and correct me if I am wrong but I don't think I am able to adjust any "cv" settings. I just wanted to find out if changing the pc board would fix my problem. If I keep running them they way it is now,eventually the one with sound will wipe out the gearing in itself trying to pull the other engine and the 16 cars I have them pulling. Or would I need to change both boards to somewhat match them up. I have another pair of engines that both have sound and run equally with no problems. I do have another engine without sound so maybe switching the boards will be an easy way to fix my problem. jward, where in Pittsburgh are you, I'm in monroeville. After I retired I decided to set up my 40 year old trains for something to do. I have a small platform, 2-4ft X 6ft boards together one length wise and the other sideways,10ft long in the back, just something to play with in the cold weather,it's taken me 2 years to get the track finished.

[Hunt]

The E-Z Command Control Center cannot program any decoder by user supplied CV number.

Replacing the decoder may improve the situation but to significantly improve your situation  – consist  your sound equipped GP7 with another one just like it.

[jward]

you are finding the fatal flaw of the ez command. try to find somebody nearby who can program these for you. decoders are fully adjustable and this customization is one of the main advantages of dcc over dc. when I first got into dcc I successfully speed matched two locomotives with wildly different gear ratios (12:1 and 32:1) that under dcc would never be able to run together. by adjusting the cvs, I was able to get them to run at the same speed.

cv is configuration variable, and by changing the numbers programmed in them you can change many things such as speed curves, setting up the locomotive to run long hood first (as many gp7s ran in real life) and many other things.

it is my opinion that changing the decoder without having a way to adjust these cvs will not help you get the result you desire. your locomotive will still run at whatever speed is the default for the decoder unless you change them.

[Mr Mechanic]

I think what I am going to end up doing is buying 2 pc boards -Walthers #524-139 and installing them in both so then they should run close enough to run them together. For me, that should be the easiest to do. I'm not really worried about having sound,most of the time I turn off the sound, the metal wheels I used to replaced the original Tyco plastic ones make enough noise for me.

[bapguy]

look at a Digitrax PR3xtra. It's a computer interface. You hook it up to a PC through a USB port. It comes with the install cd and power supply. You then download JMRI which is free. The PR3 hooks up to a programming track, JMRI reads and writes CV values to the decoder. You keep a file so if the decoder gets re-set, just reload the values using decoder pro.  Joe

[Hunt]

I think what I am going to end up doing is buying 2 pc boards -Walthers #524-139 and installing them in both so then they should run close enough to run them together. For me, that should be the easiest to do. I'm not really worried about having sound,most of the time I turn off the sound, the metal wheels I used to replaced the original Tyco plastic ones make enough noise for me.

If you have not already done so, go to the NCE website and read the instructions for their BACH-DSL decoder so you know what you are getting, what is required to install and set up the decoder.

Should the locomotives not run well in consist you will be able to have someone speed match them for you.

[Mr Mechanic]

I went to the NCE website and read the instructions for installation and will have no problems installing them and it looks like they work without tinkering,adjusting. Just as long as I install one in each engine, there shouldn't be a problem with them working together. I have been a mechanic all my life and have repaired everything from weed wackers to tractor trailers, about the only thing mechanical I haven't worked on are real trains. Spent 28 years working on the trucks that deliver your mail. I THANK all that have replied and the help will always be appreciated, always ready to learn new things.

Thanks again to all
Stanley Klepacz
Monroeville PA

[jward]

so you're going to sacrifice the sound in the one unit?

[Mr Mechanic]

Yes it will remove the sound board out of it. I will install the new board in the non sound unit first and see if it runs any closer to the speed of the sound unit,if it does then the sound will stay,if its too far away on the speed,out it will come. What I have done in the mean time is run the GP7 non sound and consist it with a GP38-2 non sound, that was my last purchase, and they are running fine together, it's just that"transformer hum" that gets to me. Being retired and raising 2 of my grand daughters-13 and 14 and violin lessons and band and jazz, I need to wait a while for the green stuff to "waste" on my hobby. Most of the time I run them with no sound and no light because of the E-Z command unit I have for power. Running 5 engines and no problems so far. Why do you ask? Want it if I remove it?

[jward]

no, it just seems a waste of money to buy a sound unit then take the sound out over what is essentially a programming issue. I would imagine somebody at the local model railroad club would be willing to adjust the cvs for you if you asked. I can understand the frustration with the motor noise in the non sound unit so a replacement of that decoder should solve that issue. the nce bach-dsl decoder was mentioned. are you aware that this decoder is meant to be hardwired into the locomotive, not plugged into an 8 pin receptacle? a decoder with an 8 pin plug would work better for you.

[rogertra]

no, it just seems a waste of money to buy a sound unit then take the sound out over what is essentially a programming issue. I would imagine somebody at the local model railroad club would be willing to adjust the cvs for you if you asked. I can understand the frustration with the motor noise in the non sound unit so a replacement of that decoder should solve that issue. the nce bach-dsl decoder was mentioned. are you aware that this decoder is meant to be hardwired into the locomotive, not plugged into an 8 pin receptacle? a decoder with an 8 pin plug would work better for you.

Here we go again.

JMRI DecoderPro.   It will program any decoder and you do not need to know what the CVs are, you just tell JMRI DecoderPro what to do and it already knows the CVs.

Cheers

Roger T.

[Mr Mechanic]

Like I had mentioned before, I am new to DCC. I purchased the GP7s because they were both Pennsylvania RR, had different numbers and were on sale. I purchased most of the items before the track was ready to use. I bought the E-Z Command because of the price and it would run the DCC. The cost of other DCC controllers is out of my price range. I had no idea of the differences between the sound and non sound units. I am finding out all of this as I go along. There were no foot notes that stated " Our sound and non sound units run differently and the non sound units hum,this is normal" I didn't find this out until I had sent the the non sound unit, that I thought was defective,back to Bachmann and was told there is nothing wrong with it. Installing a hard wired board is no problem at all, disassembly and soldering in the new board is something I have no problem doing. I have taken a few units apart and cleaned out the excess globs of grease that are shipped with. Just got my Labelle lubrication kit and will be cleaning and re lubing all of my units. Thank you for the JMRI DecoderPro web site. I had taken a quick look and just might be something that would be helpful. I don't know of any local Model RR clubs to help re program my units to run together and would I still be stuck with the hum in the non sound unit?