Dodgy DCC Socket

[Chrissaf]

I bought a brand new Princess Locomotive, tried it on DC ran perfectly up and down a straight piece of track. Anyway, I run DCC so I bought a TTS Decoder for it. I fitted the decoder into the loco tender with great difficulty (there is a thread on here about that), in fact I think there is even less room in the tender than when I fitted sound into the loco body of the previous version. Put it on my layout it doesn't do a thing. So I took the decoder out and tested in the tester works perfectly. Anyway after testing everything, I tracked it to the DCC socket, fortunately I had a new one that I was going to use for the conversion of another loco. It was an intermittent connection. When I desoldered the old one I found that whoever wired it up basically was soldering bits of uninsulated wire 1 mm long, I suspect one of those connections was soldered to the insulation.

It all works now, a bit annoying, trouble was with the old socket it occasionally worked. Before anyone says I am criticising Hornby, I am not, just pointing out a possible issue if you loco doesn't work. It was probably all the messing around in the tender trying to get the sound to fit, that disturbed it, but it probably would have in time. I also had to adjust the pickups in the tender, they weren't touching the wheels. The socket I replaced it with was one from Peters Spares, a much better design, although I assume Hornby make them.

[96RAF]

There have been reported issues with sockets before, usually solder bridges across unused tracks in DC rig but coming into play when a decoder is plugged in. There have also been occasions whereby pickup wires have been connected to the wrong pins, causing a short when a decoder is  installed. If you suspect a DCC vs DC problem then it is worth lifting the socket and inspecting the workmanship, but only if you are confident at doing this type of investigation, which will actually help when you report the fault back to Hornby. If you are not happy investigating to this level then contact your retaIler for an exchange.

[ColinB]

I actually changed the socket, yes electronics used to be my job so no problem. What it was, was whoever soldered it decided to solder the wires on the underside of the 8 pin DCC socket, they should be pushed in from the top to reduce strain on the wire. What they had done was to only strip about 1 mm from the end, and basically solder to the track not using the hole, so I suspect when they soldered it they probably soldered the insulation. So as long as nobody disturbs the DCC socket it sort of works. I come along and fit a TTS decoder which meant disturbing the DCC connector as I tried to fit it in. The annoying thing was it took a long time to find, as I checked all the connections on the tender very carefully, I just could not understand why it worked on the tester but not on the loco. I even measured the voltages on the pins of the DCC socket, but I suspect by pushing on it with the probes, made the connection. Anyway, I replaced it with one I was going to use for a DCC conversion, and have reworked the old circuit board so it does not have those individual push in pins. I hate to say it but those circuit boards are old hat, we stopped using that type in electronics years ago, too unreliable, you can get a decent "plated through hole" type one that would give far less trouble. Their one looks like ones I used to etch with ferric chroride years ago. The reason they have so many issues with shorting tracks etc, is if you look at the PCB the gaps between the connections are two small, they are using etching technology to make them, most modern processes use a deposit process where copper is deposited onto the board. Its cheaper and you don't waste copper and get thinner tracks. They are also easier to solder to.