8 Pin DCC Decoder Issues

[vito_bellissimo]

Hi all, I am using a standard 8-pin Hornby decoder to convert my DC 0-4-0 loco to DCC. During the installation, the black coloured wire coming out from the decoder snapped off and I carefully soldered the wire back into the ends of decoder. After I followed the procedure of the 'Smokey Joe 0-4-0 locomotive DCC installation' instructions done by Hornby, I tested to see if the locomotive functions all fine. It unfortunately doesnt function, but I do hear a buzzing noise and a slight jittering sound when placed onto the DCC track. 

Any troubleshooting can be done here? Does me soldering that black wire back into the decoder damage the decoder itself? 

[2e0dtoeric]

I would suggest you have either soldered the wire back into the wrong place, or you have 'bridged' two connections on the tiny board.

For the motor to make a buzzing noise, but not spin, it is 'seeing' a/c volts straight from the track, and if you keep doing it, one of the coils in the motor will burn out.

Do you have another decoder of the same type to compare your repaired one with?

Which 8-pin decoder have you used - there are several.

As the forum won't let us post pictures, for the moment, I can't ask that you photograph it, so we can see where the wires are, and nobody can post an image of one, either, unless they can 'link' to an image on a different site.

-

edited to clarify a question.

[vito_bellissimo]

I'm currently using a standard Hornby 8pin Decoder (R8249). I do indeed have another exact intentical decoder. I'll try to see if this other decoder works on the loco. But before I do that, Ill double check if all the soldering from the first decoder isnt being 'bridged' to other connections, etc. 

Kind Regards. 

[2e0dtoeric]

Let us know how you get on, please.

[vito_bellissimo]

I tried resoldering the wires to the decoder back in using a photo of the Hornby decoders wiring pattern on the internet as a guide. But still no luck with it. I feel hesitant in using my other decoder as I don't want to find out that it doesn't work on that decoder either. 

I also tried used another spare motor to see if it was an issue with the motor or to see if I some how burnt it out. I soldered everything to this spare motor and yet still nothing works, but still the same old 'buzzing' sound. 

I assume now that the source of this issue is from the some what mediocre decoder I am using.  

[96RAF]

As you have 2 matching R8249 decoders surely it is a simple matter to compare the two to see exactly where the black wire that fell off the one is attached to on the other.

Noting also that wires are connected to solder pads on both sides of the decoder, 5 on one side and four on the other.

Rob

[Phil_Spiegel.]

BEFORE substituting a decoder in a dodgy situation with another, known good decoder ... which might well end up with 2 dead decoders ... I would recommend carefully checking the installation, and isolation of the existing setup.

As I say frequently in another forum: ' Have you got a multimeter ??'  ... a cheap digital meter can be bought for less than the price of a single dcc decoder ... so EVERYONE installing decoders should have one to check....

CHECK for isolation of the motor from the chassis and the track pickups (with dummy plug removed)

[some batches of locos have had wires soldered to other connectors, which was no problem in ananlogue, but would damage a dcc decoder - check wiring/continuity from EACH wheel back to the black or red wire positions]

CHECK that when an 8-pin decoder is plugged in, the pins do not project sofar as to make contact with metal beneath the socket - a piece of plastic or insulating tape beneath the socket is a good idea.

A cheap meter will probably give an inaccurate voltage reading for the ACTUAL dcc track voltage - but this is not a great problem when it is simply being used to check whether the dcc track voltage (whatever it shows LEAVING the controller) is the same (when no locos are running) AT ALL PARTS of the dcc layout ... and that when a loco is running, that the voltage does not drop very much (no more than perhaps 2V at the furthest part... preferably less.   A cheap meter will identify short or open circuit without a problem, and show the motor resistance (between orange and grey)

Rather than use the basic Hornby '8-pin' decoder for locos without lights; and with tight spaces - I find it useful to use the '4-pin' version of the same decoder (ie only 4 wires factory intalled) - intended for the sentinel shunter etc - fewer wires to get in the way - but otherwise the same decoder.

[vito_bellissimo]

I currently do not have the other DCC decoder as it is being used by a friend on another loco he is borrowing. I do have a multimeter handy which I will use to see who the colprut is in this issue. I'll let you guys know and thank you all for your help here so far.