TheSnapper Posted April 5, 2014 Share Posted April 5, 2014 Just fitting a Digitrax decoder to a Heljan 0 Gauge Class 33 for a friend. For simplicity, is is possible to "insert" the decoder in betwen the motor & the Heljan PCB? By "insert" I mean connect the Red & Black to the PCB "Track" screw terminals to energise the chip. Then disconnect the "motor" terminals from the PCB & connect them to the Orange & Grey on the chip Will it work? Will the lights & fan work? Or is there a better way? Grateful for any suggestions! Tim Link to comment Share on other sites More sharing options...
Manxman110 Posted April 5, 2014 Share Posted April 5, 2014 Hi Tim The best way is to remove the Heljan PCB entirely and then hardwire the connections to the chip along the lines that you suggest. It is probably best to insert a suitable resistor in the line to each of the lights to ensure that you don't blow the leds. You will find that you have separate connections from each bogie for the pick up so make sure that you have the wires from the same side of each bogie. Also watch the motor wires and test that joining the motor wires has each motor running in the same direction. I am assuming that your Digitrax decoder has enough muscle for a Heljan loco as with two motors they can draw up to 3 amps. I have used Loksound or Zimo sound chips in my Heljan diesels and all work well but while they are not difficult to wire up it takes time and you need a little patience. Regards David Link to comment Share on other sites More sharing options...
TheSnapper Posted April 6, 2014 Author Share Posted April 6, 2014 David Thanks for the info. I have installed various chips into Heljan locos in the past, the latest being a Loksound V4 XL into a Heljan Deltic (with 5 speakers!), again for a friend. In that case I removed the Heljan board and made a Plasticard carrier, and wired-up everything to the screw terminals. For my personal use, I prefer Zimo chips, both the 645 & the 695 series. For the 33 I was after a quick install, by wiring-in the Digitrax DH465 (non-sound, 4 amp/6 amp peak) decoder and mounting it atop the Heljan PCB. It's quite small, so it will fit and has flying leads, not screw terminals. I am curious to know whether it would work, by connecting it in parallel the Red/Black to the Heljan board, then wiring the Orange/Grey from the chip to the motors. Therefore the board will still be connected to the original pickups, and now getting the 16v AC (or whatever) from the track. The question is, will the lights and/or fan still work or will it blow? Regards Tim Link to comment Share on other sites More sharing options...
two tone green Posted April 6, 2014 Share Posted April 6, 2014 5 speakers, gosh ! What did you use and how did you wire them up Link to comment Share on other sites More sharing options...
Manxman110 Posted April 6, 2014 Share Posted April 6, 2014 Hi Tim My money would be on a rather spectacular smell of burning accompanied by some realistic smoke effects. I don't think the Heljan board is equipped to handle A/C and certainly not at 19 -21volts. The board is configured to handle 12-14 v DC and whilst there is some limited smoothing on the board I don't think that it amounts to full scale rectification. The LED will certainly not respond well to A/C and the higher voltage even with the resistors in line is going to overdrive them and the combination will destroy them. Similarly with the little DC motor that drives the fan - a neat blast of A/C will fry it in seconds. I think the only debate will be how long will the DCC supply go before it goes into short circuit shut down. Whilst the board is scrap in any event I think that what you are proposing is an expensive experiment which is likely to see you having to replace all the LED and possibly the fan motor as well - I wouldn't even contemplate it. Kind regards David Link to comment Share on other sites More sharing options...
TheSnapper Posted April 7, 2014 Author Share Posted April 7, 2014 Thanks David - good advice - I shan't bother then.....! TwoTone - I can't exactly remember to be honest, but I think it was: 2 x 8Ω at each end in parallel ( = 4Ω each) Then these in series (=8Ω,) Then these 4 in parallel with an 8Ω speaker in the fuel tanks firing downwards (=4Ω) Just did it to get a meaty omnidirectional sound for a BIG loco! Tim Edit = Ohm symbol now showing as a question mark...??! Link to comment Share on other sites More sharing options...
two tone green Posted April 7, 2014 Share Posted April 7, 2014 Are you taking all them off one output from the decoder or spread over the two available outputs. Link to comment Share on other sites More sharing options...
TheSnapper Posted April 7, 2014 Author Share Posted April 7, 2014 I think I tried both, but then settled for all off the same output Tim Link to comment Share on other sites More sharing options...
two tone green Posted April 7, 2014 Share Posted April 7, 2014 Watch the volume, you could be heading towards problems. Sorry, seem to be moving away from the original question. Link to comment Share on other sites More sharing options...
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