olly Posted January 8, 2017 Share Posted January 8, 2017 Can anyone give me a few pointers on how to fit a decoder to the Lima-Hornby D445 I have enclosed a Picture of the circuit board. I know the basics of fitting a decoder like separating pickups from the motor but not sure what to do with the resistors etc . Is there a way I can modify the circuit board ? Or would it be better to do away with the circuit board and just hardwire the decoder ? /media/tinymce_upload/e24aa546bdd51e78dc47cc5c8da7b0c6.jpg Link to comment Share on other sites More sharing options...
pidder Posted January 9, 2017 Share Posted January 9, 2017 The connections to the motor and pick-ups seem to be easily identifiable. I would assume the circuit board components are to prevent radio interference, which I believe a decoder does anyway. Personally, I would remove the circuit board and just hard-wire the decoder to the appropriate motor and pick-up wires. Wonder if anyone else thinks differently? Link to comment Share on other sites More sharing options...
Chrissaf Posted January 9, 2017 Share Posted January 9, 2017 Does the loco have lights. The board has got contact positions that seem to be in use marked LED. If there are LED lights on the loco then with suitable modification they could be connected to the function outputs of the new DCC decoders..By the way the two blue components in the middle that look like resistors marked L1 & L2. These are not resistors, they are ceramic coated inductors, hence the L prefix labels. Note the SMD (Surface Mounted Device) resistor to the right, this is labelled R1. R for resistor, C for capacitor, D for diode & L for inductor. Yes I know inductor doesn't have an L as the first letter, the naming convention is historical..D1 & D2 will be providing the forward / reverse logic control for the LED lighting. R1 is probably the current limiting resistor for the LEDs. C3 due to its size, type and hence larger value, is probably an anti-flicker capacitor for the LEDs. Link to comment Share on other sites More sharing options...
pidder Posted January 9, 2017 Share Posted January 9, 2017 Chrissaff I learn something new every day... Why do the inductors have colour codings, is this the same as resistor codings? Perhaps you could also remind us of the appropriate wires to connect forward and rear lighting? Link to comment Share on other sites More sharing options...
Chrissaf Posted January 9, 2017 Share Posted January 9, 2017 Resistance is measured in Ohms, Capacitance is measured in Farads & Inductance is measured in Henrys. The size and type of inductor shown in the photograph has a value measured in uH (1uH is one millionth of a Henry)..The colour banding denote the value in a code.The colours on L1 & L2 look like they might be Brown, Brown, Black it is hard to tell as colours don't always get accurately rendered in a web page photo, but if correct then that would be a value of 11uH..The LED forward / reverse wiring post I made can be searched for. Off hand, I can't remember where I posted it. Link to comment Share on other sites More sharing options...
Flashbang Posted January 9, 2017 Share Posted January 9, 2017 The band markings are the value of the inductor in micro Henrys. Much the same as resistor values differ inductors do too. This site gives the details... http://www.instructables.com/id/Inductor-Color-Code-Guide/ As suggest by pidder above. Its best to remove the whole circuit board. Its no longer needed when a decoder is fitted. RF suppression is from the decoder. Directional light is from the decoders function wires - Blue is common Positive to all functions. White and Yellow are forward and rear lights negatives. Don't forget to add a series resistor into the LEDs wiring. I would start with a 1K0 (1000 Ohm) resistor and work up in Ohm value to dim the LEDs if needed i.e. values of 5K0 or 10K etc can be trialled. Link to comment Share on other sites More sharing options...
olly Posted January 9, 2017 Author Share Posted January 9, 2017 yes the loco has LEDs fitted the are on a small PCB at each end they look like the have a SMD resistor fitted .I will post a picture of the LED Link to comment Share on other sites More sharing options...
Flashbang Posted January 9, 2017 Share Posted January 9, 2017 Then you wont need the LED series resistor(s) mentioned in my post above. Just ensure the Blue decoder wire connects to the correct positive tab on the LED PCB. Link to comment Share on other sites More sharing options...
olly Posted January 9, 2017 Author Share Posted January 9, 2017 photo of the LED /media/tinymce_upload/215ae3f496cab011515c43231834f9d6.JPG Link to comment Share on other sites More sharing options...
Flashbang Posted January 9, 2017 Share Posted January 9, 2017 The SMD on the right marked 1001 is a SMD resistor with a 1K0 (1000 Ohm) value.The brown unmarked device on the left I suspect (guessing here) is a diode. This can be used with the Function output wires of the decoder without any thing else. Connect Blue wire to where red wire is currently and white or yellow (depending on LED light colour) to the black wires former connection. If its a white LED used for the front forward direction headlight use then the White decoder wire which goes to the negative connection, this wire would also feed any red LED(s) in the rear. The yellow wire feeds the rear white headlight light and front ends red lights where fitted. Blue wire is common positive to all. Link to comment Share on other sites More sharing options...
Flashbang Posted January 9, 2017 Share Posted January 9, 2017 I suspect this is how its connected...http://i190.photobucket.com/albums/z311/Flash_bang/LED_zpssbk1vm2y.jpg Link to comment Share on other sites More sharing options...
olly Posted January 9, 2017 Author Share Posted January 9, 2017 Thanks flasbang Link to comment Share on other sites More sharing options...
Chrissaf Posted January 9, 2017 Share Posted January 9, 2017 To me the brown thingy looks more like a SMD Capacitor....compare it to the C2 (capacitor) component on the main PCB board.....they are very nearly identical. Link to comment Share on other sites More sharing options...
Flashbang Posted January 9, 2017 Share Posted January 9, 2017 Yes its feasible for it to be a capacitor to offer some simple flicker free illumination? Link to comment Share on other sites More sharing options...
Chrissaf Posted January 9, 2017 Share Posted January 9, 2017 Or perhaps a fading in and fading out component. Place a capacitor across a LED and it can perform that function. Link to comment Share on other sites More sharing options...
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