Most likely this is the case, it would explain the result you had. Problem is, it's hard to test - just the pressure of putting multimeter probes to the spot to check continuity can be enough to push a cracked trace together and it tests just fine. Until you let go and it opens up again.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I think that is probably the case Randy. There is a plated through hole right where the tab broke off that would have connected a trace from the top to the bottom. Hard to tell if the plate through is compromised or not, but I'm assuming so. Adding that additional jumper is probably a good idea.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
If that broken tab also happened to break a trace that fed something at the opposite end of the decoder, it would account for this. Normally there would be traces the length of the board connecting the front and rear track tabs, so normally it should work fine with input at just one end. If something broke there, then the components that receive the signal may have been cut off, and soldering on where the broken tab was then fixed this issue. However, if this indeed is the case - I would sonsider running a jumper wire front to back to repalce that trace, because it sounds like perhaps some power is now coming from the front truck and some from the rear, but they are not electrically connected, so you could get unexpected stalls as the one truck that is feeding the DCC signal hits a dirty patch - in other words, because of the break, it's not working like a normal all-wheel pickup loco. One end is supply power to run the decoder, the other end is supplying the DCC signal to control it. A jumper wire from the broken tab solder point to the opposite end will make sure it works as originally intended.
Then it must've been the gremlins....
Mike Lehman
Urbana, IL
mlehman Yeah, that is odd behavior. I agree that one lead should've been enough. But there's probably a simple explanation. If my programming track or loco wheels are a little dirty, sometimes there's not a good enough signal to get a good readback from the decoder and you get the error message. It may have been the case that with just the one lead hooked up, there wasn't enough signal, while with both connected, it was good. Plus the Tsunami requires a bit higher signal level than a non-sound decoder anyway. My guess is some combination of those factors caused this.
Yeah, that is odd behavior. I agree that one lead should've been enough.
But there's probably a simple explanation. If my programming track or loco wheels are a little dirty, sometimes there's not a good enough signal to get a good readback from the decoder and you get the error message. It may have been the case that with just the one lead hooked up, there wasn't enough signal, while with both connected, it was good. Plus the Tsunami requires a bit higher signal level than a non-sound decoder anyway. My guess is some combination of those factors caused this.
I wasn't using just one lead though .... I extended the front truck wire to attach to the same side rear tab - so all eight wheels were picking up. Just finished polishing the wheels on a new build as well.
As I said before, the sound was working just fine - so there was good contact .... just not sending / receiving the information packets.
cacole That shouldn't have been necessary -- the decoder should work just fine with only one end connected to track power. Before installation, I test all Tsunami decoders by connecting the tabs on only one end to track power with a set of alligator clip leads.
That shouldn't have been necessary -- the decoder should work just fine with only one end connected to track power. Before installation, I test all Tsunami decoders by connecting the tabs on only one end to track power with a set of alligator clip leads.
That would have been my thinking as well, but that proved to be not the case. The tab that broke off connected to a circuit trace that immediately went through three small components. It may be possible to use only two tabs providing they are the two at the "front" end of the decoder where the circuitry is.
Regardless, without the one front tab connected, all I had was sound. I could not read or write on the program track and could not run the engine. After re-connecting the truck wire to the front tab circuit trace, everything was restored to normal.
Ended up pulling the decoder and managed to solder the truck wire to the circuit trace itself right beside where the tab broke off. I can now read / write and everything works as expected.
Apparently on Tsunami decoders, it MUST have track feeds at BOTH ends to function properly.
Ok - I hooked it up as such. When placed on the track, the sound immediately came on (as expected). I dialed in the address (assuming it was the same as the cab number) and nothing. Placed it on the program track to read the address and keep getting an error message. (?)
I know it "shouldn't" make a difference, but something isn't right here ....
Obviously, the front and rear trucks pickup from the same rail on both sides.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Sure you can. Look at the diagram that came with the decoder. I have the Tsunami also.
I have a Tsunami decoder in an Athearn GP15-T that has a broken truck tab on it. Could I expect it to work properly if I extend that truck wire to the rear tab of the same side ?
Looking closely at the circuit traces, that tab does feed through a few small unknown components.