Wobblinwheel Posted April 6, 2016 Share Posted April 6, 2016 After successfully fabricating a little DCC "box" that contains two decoder 8-pin sockets on the inside, with three phono sockets on the outside. One phono socket for the "track power" (red and black pins on decoder sockets) that the DCC controller plugs into. The other two phono sockets to select which decoder I want to run to the track, which use only the orange and grey "motor control" wires to power the locos on the track. One decoder, the Hornby R8249, works really well on certain locos (the N gauge Dapol N7, in particular) and the Digitrax decoder works better on the N gauge locos that require more "juice" to run them and a non-flickering headlamp. This has been working very well for a couple of weeks now until...... I decided to re-design the enclosure (make it smaller), and "hardwire" the decoders to the phono receptacles to eiliminate the 8-pin plugs and sockets, and tuck-away some unused (lighting) wires from the two decoders. I have hardwired many decoders in my day, so this ain't my first rodeo. Guess what? NEITHER decoder works any more!! NOTHING! I have double -checked my wiring (black and red going in, orange and grey coming out). Couldn't get any simpler.....but neither decoder works any more. Anybody got any ideas on what kind of freak phenomenon just occurred?? I am stumped, buffaloed, and bamboozeled...... Link to comment Share on other sites More sharing options...
Chrissaf Posted April 6, 2016 Share Posted April 6, 2016 Maybe stating the obvious and getting 'grandmother to suck eggs' and all that, but have you connected the red/black wires to your controller progamming output and read the CV's to see if any previous settings have been corrupted. You could try writing decimal value 8 to CV8 to perform a factory reset which might help, this will also reset address to 003 if previously changed by you. Link to comment Share on other sites More sharing options...
Wobblinwheel Posted April 6, 2016 Author Share Posted April 6, 2016 Unfortunately, my system doesn't "read" CV's, but I have done the CV8=8 thing to no avail. One decoder was set to address "1" and the other "2". I have checked the voltage, on the red and black wires of each decoder, and each is getting proper voltage. Nothing is coming out of grey and orange when throttle is applied. This is just plain weird....what could I have done to BOTH decoders at once?? I need a drink..... Link to comment Share on other sites More sharing options...
Howbi Posted April 6, 2016 Share Posted April 6, 2016 @wobbly..........just a thought...your problem may have been caused by using the phono plugs & sockets...... if already live when you insert the power supply plug you can get arcing momentarily as you try to line up the plug to engage and this can confuse and damage a decoder.....I bricked one by just touching a 9v battery on to a loco's wheels for a test and arcing occurred as I tried to keep the battery terminals in constant contact and suddenly it stopped with a wisp of acrid smoke......HB Link to comment Share on other sites More sharing options...
Fishmanoz Posted April 6, 2016 Share Posted April 6, 2016 Seen any wisps around Wobbly? Didnt accidentally touch inputs to outputs somewhere along the line, that will call in the wisps every time. Link to comment Share on other sites More sharing options...
Wobblinwheel Posted April 7, 2016 Author Share Posted April 7, 2016 No "wisps" and nothing seemed hot or even warm. I've never really had problems with phono plugs arcing because of their design. They tend to not do that, but anything is possible. I did use my butane soldering iron which does produce a lot of heat around the sides. Maybe I cooked 'em, although there's no indication of that at all. I need to look at the situation again and try to figure it out. I may not ever know.... Link to comment Share on other sites More sharing options...
Wobblinwheel Posted April 7, 2016 Author Share Posted April 7, 2016 My last reply showed up first on this post. Never seen that happen before, either. I think I have officially entered the "Twilight Zone".... Link to comment Share on other sites More sharing options...
2e0dtoeric Posted April 7, 2016 Share Posted April 7, 2016 'Leaky' earth on your soldering iron? A static (etc) discharge through the iron's bit to the decoder would fry it quite nicely. Or, as suggested, those 'orrible phono plugs can momentarily short as you insert or remove them, especially if there is a large capacitor in there for smoothing the dc in, and you hadn't discharged it! (Do you have a high value resistor across the caps, to discharge them when power is removed?) Link to comment Share on other sites More sharing options...
Wobblinwheel Posted April 7, 2016 Author Share Posted April 7, 2016 I'm just not sure I can understand this "arcing" and "shorting" business. While I'm using RCA "phono" plugs and sockets, this arcing and shorting is a real "stretch". The extended center pin of the plug (let's call it "+") inserts into an insulated hole in the center of the socket long before the outside "ring" around the plug ("-") can make contact. Litterally IMPOSSIBLE to create a "short"! As far as "arcing" goes, when a loco is placed on a DCC-powered track, is it not possible (or very much LIKELY) that an arc is going to occur? How about when saiid loco goes over points? I've SEEN "arcing" occur! It doesn't "fry" decoders every time it happens! While this setup I'm using is not the same as "normal" DCC-powered track, it pretty much simulates the process electrically. I can't tell you how many times I've plugged and unplugged this stuff without issue. By hardwiring the decoders to the sockets (unbelievably simple), I managed to do something dreadfully wrong..... Link to comment Share on other sites More sharing options...
Wobblinwheel Posted April 13, 2016 Author Share Posted April 13, 2016 After taking a break from this for a while, I looked into it again with a clear head and a calmer demeanor, and found absolutely nothing wrong, except neither decoder works. Reset each back to default. Nothing. Fired-up my new butane soldering iron to see exactly how much excessive heat comes from the sides of the burner, and yes it is...EXCESSIVE. This is the only thing I can figure is the heat got 'em. Looked at both under a magnifier, and see nothing wrong, but that doesn't mean anything, I guess. Now I know to turn the fire off when soldering in tight spots! Didn't visibly damage anything else in the little box, all those tiny wires, etc. Still weird.... Link to comment Share on other sites More sharing options...
Wobblinwheel Posted April 13, 2016 Author Share Posted April 13, 2016 Anybody got a R8249 they want to get rid of.......CHEAP? Link to comment Share on other sites More sharing options...
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