The first one I built works great.
However, after completing the first decoder I have built 2 more and have been unsuccesful in making them work. On the one I just completed I have verified every connection and placement of all components. All match the schematics and diagrams and all match the one that works. I have the 22 volts and the 3.25 volts in all locations. I have cut the trace on JP1 and jumpered trace 3 on JP2.
I have done a comparison voltage reading at various points on the circuit boards between decorder 1 (the working one) and decoder 3. At most points they are identical, the differences are significant lower voltage at pin 3 of J1 and pin 3 of U2; no voltage at M1 and M2; and no voltage at R2.
Are there test points and readings at these point that I can troubleshoot?
Help!
What are these decoders, More info needed.
Jay
C-415 Build: https://imageshack.com/a/tShC/1
Other builds: https://imageshack.com/my/albums
Definitely need more info on what this is. Google hints this may be something for large scale trains, since one hit was Garden Railways magazine?
But in general - are those ICs in sockets or soldered right to the board? If in sockets, swap components. If soldered directly to the board - one of them could have been damaged by excessive heat when soldering. And check for solder bridges between pins, it's VERY easy to get a little too much solder on a pad and have it touch the adjacent pin. Use a magnifier.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
This is a DIY DCC decoder that was featured in a Garden Railway article. I would suggest you go to their website and review the reader comments and the links to the corrections...
Modeling BNSF and Milwaukee Road in SW Wisconsin
Thanks for your reply. I have gone to their website, did find the problem, and have corrected it. The decoder now works as designed.