Blackbird Posted February 17, 2015 Share Posted February 17, 2015 I have an early Cl 31 (R2420) running on DCC for many years. The running lights failed, in that the lights for one direction (not the boy band!) were always on. Examination found that the resistors R10 & R11 were running hot (55C). After consulting the service sheet for part no.s noticed that a cab light option was available attached to cab bulkhead. So I purchased a new PC board and a pair of bulkheads with cab lights. Fitted PC board and running lights are now OK. Now question is, where do the cab lights wires connect? The length of the wires, as supplied suggest they connect directly to the PC board. There is one 'unused' terminal at each end which I presumed to be the -ve feed to the cab lights, with the +ve being the common +ve for the running lights. However I can't measure any output to these terminals. That is assuming the cab lights would be F7, (the green aux wire connected to the PC via the 8 pin connector) The PC board is common to all variations of the Cl 31.If anyone has a Cl 31 DCC with cab lights and can look inside, can you advise as to how they are connected? and the function button.Second question, does anyone know why the PC board is so complex? all of those electronics (transistors, capacitors, diodes and resistors), seem to be only for the directional lighting, the track feeds and motor supply go directly to the decoder, so what is so special about the lighting? Can't find any electrical schematics for Hornby locos on their site or service sheets!. All of my other DCC locos have direct feeds (+resistors) from the decoder.I have retro- fitted cab lights to many of my other DCC diesel using LEDs + 1K ohm to the F8 purple (Aux2) with success (F8 is the default for factory fitted cab lights in Ba**mann diesels) Link to comment Share on other sites More sharing options...
96RAF Posted February 17, 2015 Share Posted February 17, 2015 BlackbirdNot a Class 31 but I have a Class 56 DCC ready and it has a long complex pcb as well. As you say why all that for a few connections and the odd resistor.I noticed on Fleabay that there are various revision states for my board with different part numbers, as evidenced by the R1, R2, etc at the end of the board number. The pcb was also clearly printed LT-1, LT-4 in some of the advert photos.I was told by HCC that some 56s had boards that would/wouldn't support certain lighting effects, like strobing, flash, etc when used with an appropriate decoder such as the Sapphire which supports these effects.I also wanted to add cab lights using the obvious vacant terminal at each end of the pcb with the same result as you - no output when the associated function was activated.Adding even simple external connection schematics to the Hornby library on the website would be a bonus, without having to give away the secrets of the pcb full schematic.Maybe your 31 falls into a similar category. Link to comment Share on other sites More sharing options...
Blackbird Posted March 9, 2015 Author Share Posted March 9, 2015 Hi RAF96, thanks for your input. It seems none of our DCC experts has an answer to this query? I have contacted HCC who initially, advised " they could not advise on this as it involved a modification and would invalidate any warrantee" ???I have since made further investigation and testing of this 'complex' circuit board, and found: The green wire, pin 3, aux output C, has no connection to the circuit board. The unused terminals on the circuit board are connected to the directional circuit lighting.So, question is; does anyone have a class 31, with cab lighting, and can advise as to how the cab light LED's are connected? Link to comment Share on other sites More sharing options...
96RAF Posted March 9, 2015 Share Posted March 9, 2015 Peters Spares is showing X9533 as Cab Light with pcb and X9576 Cab detail light box with pcb. I wonder if these are both connected with getting the cab lights to work. Your pcb looks just like my CL56 one in that there is a spare contact at each end. This is a nice review of the Class 31 http://www.modelrailforum.com/forums/index.php?autocom=custom&page=H-R2420 This decoder installation guide mentions 12 pins socket. 8 pins for the decoder so I wonder if the other 4 pins are for the cab lights module(s). http://www.bromsgrovemodels.co.uk/hornbycl31dccinstr.htm Link to comment Share on other sites More sharing options...
96RAF Posted March 9, 2015 Share Posted March 9, 2015 BBJust noticed on the Bromsgrove guide second picture from the bottom shows what I guess is a cab light (yellow). Link to comment Share on other sites More sharing options...
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