Brew Man Posted July 13, 2021 Share Posted July 13, 2021 Good morningYesterday I decided to take the lid off my Wainwright H class loco as it wasn't quite seated properly. I managed to tuck the decoder into the small compartment in the side tanks and the body went back on snugly.Testing it on the track soon produced plumes of smoke through the chimney. Looked great but very short lived disappointed_relieved. I'm afraid the decoder and motor are stuffed. Well I know the decoder is as I have tested it. Pretty sure the motor is too. Looking at the H class service sheet the motor is listed as X7170, however it only lists it for models R3538/39 and 40. My model is R3631 which it doesn't mention. Can anyone confirm whether or not the X7170 will fit my model please? I'm guessing it will but would like to be sure before buying one. I've messaged Hornby but from previous experience I could be waiting a while for a response.Thanks for any help received.Decoder-wise, I'll be fitting a DP2X-UK as I think it will be a much better fit than the normal 8 pin wired types. Link to comment Share on other sites More sharing options...
Bulleidboy Posted July 13, 2021 Share Posted July 13, 2021 Good morning to you.The DP2X-UK fits perfectly - no messing around with the harness. My H-Class is not currently on the layout, but having fitted the decoder and snipped off the capacitor, it ran perfectly for forty five minutes in each direction on the rolling-road. Link to comment Share on other sites More sharing options...
Going Spare Posted July 13, 2021 Share Posted July 13, 2021 I think the only reason your locomotive is not shown specifically on the Service Sheet is that the sheet is now over 4 years old and because of the vast number of new locomotives that are being introduced, Hornby simply have not managed to keep the updating up-to-date. Dealers offering the replacement motor are not restricting its usage but, to be safe, I would query its suitability when you place the order. Link to comment Share on other sites More sharing options...
Brew Man Posted July 13, 2021 Author Share Posted July 13, 2021 @BBThat's good to know, thanks.@GSThanks, I did message the supplier that I'd identified and they knew as much as me. I'm waiting to hear back from Hornby, might actually give them a ring as it will likely be quicker.Thanks both. Link to comment Share on other sites More sharing options...
Brew Man Posted July 13, 2021 Author Share Posted July 13, 2021 Follow up:Just spoken to Hornby and have had confirmation that the X7170 will fit my model, so have just ordered one.A good outcome. Link to comment Share on other sites More sharing options...
ColinB Posted July 13, 2021 Share Posted July 13, 2021 I would be surprised if the motor has gone bang, when a decoder fries it gives off tons of smoke. The only thing is that perhaps the motor went short circuit taking the decoder with it, but that is rare. Are you sure one of the stray wires didn't touch the chassis, that normally fries them. Link to comment Share on other sites More sharing options...
Brew Man Posted July 14, 2021 Author Share Posted July 14, 2021 I'm pretty sure. I replaced the blanking plate and tried to run it DC but it didn't respond except a few bright sparks from around where the brushes are located, then nothing. I'll know more when I take it out. If it is repairable it'll do as a spare. The new one is only costing just over £13, so worth the expense IMO. Link to comment Share on other sites More sharing options...
ColinB Posted July 14, 2021 Share Posted July 14, 2021 Check the capacitor across the motor, I have had them go short circuit before now. Link to comment Share on other sites More sharing options...
Brew Man Posted July 14, 2021 Author Share Posted July 14, 2021 Good tip, thanks. Will probably take it out completely when I replace the motor. Link to comment Share on other sites More sharing options...
Fishmanoz Posted July 15, 2021 Share Posted July 15, 2021 Yes, no need to check it, just chuck it. Link to comment Share on other sites More sharing options...
Brew Man Posted July 16, 2021 Author Share Posted July 16, 2021 So I've just put a new motor in this, and - nothing sweat. It's not working either with a new decoder or in DC mode. I know the motor is working, checks out OK with DC applied direct to the brushes. I'm wondering if any of the insulation on one or more of the wired has melted and shorted to an adjacent wire when the original decoder cookedDoes anyone have a schematic of the DCC socket wiring by any chance? I seem to recall Rob having something relating to one in a previous thread. I'm getting continuity between pins 1 and 5 with the blanking plate plugged in which doesn't seem right. Link to comment Share on other sites More sharing options...
Chrissaf Posted July 16, 2021 Share Posted July 16, 2021 Does anyone have a schematic of the DCC socket wiring by any chance? Basic generic schematic for NEM652 DCC socket. LED directional lighting is optional. Link to comment Share on other sites More sharing options...
ColinB Posted July 16, 2021 Share Posted July 16, 2021 Here is the simple test I do. With a multimeter check resistance between adjacent pins, they should all read high impedance except between pins 1 and 5. Amazingly I have measured values ranging from 10 ohms to 100 ohms between pins 1 and 5, which is effectively the motor resistance (10 ohms seems very low, but the motor worked). Next put the loco on the track and check pins 4 and 8 go to the track. Now check that pins 1 or 5 are not connected to the track by measuring the impedance/resistance. I suspect in your case one of the motor wires has fell off, probably touching the chassis as it did it. That would smoke the decoder. Link to comment Share on other sites More sharing options...
Brew Man Posted July 17, 2021 Author Share Posted July 17, 2021 OK, chaps, thanks for that, I'll do some checks. Link to comment Share on other sites More sharing options...
Brew Man Posted July 19, 2021 Author Share Posted July 19, 2021 Update:Problem solved. The pick up wires from pin 8 had gone O/C. That is, they were still soldered onto the PCB but the solder point was not connecting with the pin. I'm thinking a short piece of track might have blown when the decoder cooked.It's likely that the original motor is still in tact - haven't tested it yet, but I now have a spare.Thanks for the help and advice, Colin and Chris. Link to comment Share on other sites More sharing options...
ColinB Posted July 19, 2021 Share Posted July 19, 2021 If the 8 pin pcb was one of those early Hornby ones I am not surprised. They seem to incredibly difficult to solder to, and when you do you have to be so careful that the solder doesn't splash over to the next pad. Also the pins on the socket don't always seem to make contact even though you know you soldered them. Then if by chance you leave the soldering iron on the pad for too long you either lift the track or the individual socket falls out. I am pleased to say the new ones from Hornby which they released in the last year, are tons better. Link to comment Share on other sites More sharing options...
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