After getting a little smart with these decoders, I decided to switch a pair of LEDs from one engine to another. Why? WHY??? did I try this? One engine is running fine, although neither LED will light. The second engine, the front LED will light regardless if you have the engine in forward or reverse. The motor will also not run. When I tried to reprogram the decoder, I got the dreaded "can not read cv" message. Did I just fry that decoder?
Probably not. The second engine probably is not running because the motor contacts are not touching the decoder's motor contacts. This is typical with just the LEDs lit and no motor action. Check the motor contacts. Also, what engine and what decoder?
I'll check the contacts, but I think they're touching. Its an atlas 8-40BW with the stock decoder. I've now rechecked it and I'm quite confident there is contact. With power getting to the decoder, wouldn't it at least read the CVs when trying to program?
This happens with Atlas loco's and factory installed decoders or the Digitrax DN163A0. The motor contacts of the loco aren't in proper contact with the underside of the decoder. Stay cool and run steam......
Did you switch led's or swap the whole boards? Both of the conditions you mention sound like shorts or damaged decoders. On the first one, if the motor is responding but no lights, the motor contacts are not the trouble. On the second, if the motor contacts were the only problem, the lights would work properly. Lights staying on all the time could mean that a part of the light circuit is touching the frame and/or the F0 output is fried. Most that I have damaged stayed on all the time Remove the boards and if you have a tester available test each decoder on the bench. Martin Myers
Martin, the first engine runs fine, but no lights. I think I ruined the led. I'm not concerned about that engine as it will be run in the back of a consist and lighting is not an issue. The second engine, I can turn the rear led on or off, but if I try to change it from rear to front, the rear always stays on and the front never lights. Also the motor will not run. due to the problems with the led, I do not think it is a motor contact issue.
It's hard to ruin an LED but sounds more like you put them in reverse polarity so they won't work this way. With the second engine are you sure your CV's are set for directional operation. If not the LED will always stay on doesn't matter which direction the engine runs. How are you programming your engines?
Update: Engine 1: It was indeed a polarity issue on the LED. I fixed that last night. Engine 2: Pretty sure I ruined the decoder and have ordered a replacement.
