SOLVED - Walthers/ Like-Like RS2 Decoder install (no Sound) - Can it be done?

[gbcaboose]

 Well, obviously it can be done, but I'm having trouble figuring it out. I'm installing a digitrax DN163K2. The instructions on the digitrax website say the only task is to insulate the top motor tab with son Kapton tape. This did not work. After a closer inspection I could tell the bottom tab would also need to be isolated from the frame with tape. No luck after doing that. A trip to Spokeshow's website revealed that "the entire locomotive needs to be disassembled", which I did (many many times) applying tape anywhere where I thought the motor might be making contact with the frame. Ultimately I have incased all of the exposed metal of the motor housing, with the exception of the motor tabs, with kapton tape. Additionally I have taped the frame to isolate the motor tabs from the frame. I've also made sure the connection points between the decoder and the frame are snug, and made sure the bottom motor tab is contacting the inside of the large decoder side tab.  I'm obviously missing something, but I can't figure it out.

I'm installing 2 of these and have been swapping the decoders with the frames each time with no luck.

If anyone has installed one of these please chime in. Apparently these decoders are a drop-in for the Kato RS2 (among other locos) but are supposed to work on the Life=Like RS2, even though they are internally different.

I'll attach a pic or 2 of my tape covered motor.

Any help is appreciated,

Mike

[mu26aeh]

This is from the TCS page using their decoder, but same process.  Is it possible the LED leads are touching, or does your board have SMD LEDs ?

http://www.tcsdcc.com/Customer_Content/Installation_Pictures/N_Scale/Walther/RS2/RS2.html

[gbcaboose]

The LED's are directly on the board, and there seems to be plenty of space between them and the frame.

Thanks for the suggestion.

Mike

That piece of tape on top of the decoder is just a marker to distinguish between the 2 in working with (about to destroy  )

[peteski]

Your problem description is very nebulous and not very informative.

You verified that those models worked well in DC?
What does "not work" mean exactly?
Are the decoders getting damaged when you are testing the install?
How are you testing the installed decoder?
Are you verifying (with a multi-meter set to ohms) that the motor tabs are not contacting either frame half?
Have you verified that the decoder pads which should be contacting the chassis tabs are electrically connected to the chassis?

Answers should provide a decent start for further troubleshooting.

[gbcaboose]

Both locos work well with the stock DC light-board. After my install(s) I used the Digitrax PR3 to 'read' the decoders. The PR3 is giving me a 'no decoder found' error. I then put an DCC Atlas GP on the program track and the PR3 reads and programs it just fine, so I know the PR3 and my program track are working.

I have not 'Ohm-ed it out'. That is an excellent suggestion. If I use my multi-meter to verify that there's no contact between the motor tabs (or housing) and the frame, the issue could be the decoder pad contacts as you suggested. The decoder seems to be snug. But after rethinking it, the decoder has the large side tabs (which most of my decoders don't have) which may give a false sense of snugness when I wiggle the decoder from side to side. I'll add a thin layer of solder to the pads for a tighter fit and see if that helps.

I'm at work right now, so it'll be later today before I can work on it.

Thanks Peteski,

Mike

[woodone]

If the motor tabs were touching the frame, that would cause a short! Not sure when using a PR 3 that it will show that?
It really sounds like you are not getting a good connection between the decoder and frame. You may have to put a small dap of solder on the decoder pads where it slides into the frame. This will make the tabs a bit thicker.

[peteski]

I also agree that the problem most likely is not with motor tabs shorting to the frame (but it is always a good idea to verify that since if there is a short, it usually leads to a destruction of the decoder, which would also manifest itself by the decoder not being seen). 

The other test I also perform is to touch a 9V battery terminals to the wheels or to the frame halves and see if the motor runs. By default decoders have the DC mode enabled, so it should run in DC.  But yes, having the additional information now I agree that most likely the problem is with the frame not connecting electrically to the decoder. So it is an open circuit rather than a short. I guess we'll find that out later.

[central.vermont]

Most likely a case of those damn thin Digitrash boards!!!
Thinner than the OEM board that is.

If this is the case a little tap on the corner of the tabs that hold it in place may be all that is needed.
Jon

[gbcaboose]

Well you guys nailed it! Despite the fact the the boards seemed firm and snugged in place, I put a thin dab of solder on the contact points and wedged them in place and they're running like champions.

I've actually done this on some digitrax installs on GP38's and 40's, but they were noticeably loose with obvious contact issues.

I also checked 'em with the multi-meter and they're good-to-go.

Thanks for all you're help!

Mike

[peteski]

Excellent, excellent!

Yes, for reason unknown, Digitrax uses thinner PC Board material than the stock boards for their decoders.  Solder build-up is one way to take care of the problem.

[central.vermont]

Good news Mike!!!
Those thinner boards has always been a pet peeve of mine. 

Jon