John ks

I have coloured the PCB tracks to NMRA standards (Edit forgot this was DC but tracing the PCB tracks helps to show what pads do what) Assuming the front of the loco & pin 1 on the DCC socket is as I have added to the pics The pics should explain all The small LED boards look to be wired Red wire to Red LED Black wire to the White LED Blue wire common to both LEDs If I was doing this I would connect the LED boards as I have drawn, plug in a decoder (edit forgot I was in the DC section )& test the loco without the body You should have a rear red LED & a front white LED on when going forwards If not then transpose the red & black wires (to the LED board) at one or both ends as required I cant help with assembling the loco John

the motor output from most/all decoders is PMW (Pulse Width Modulated) At full speed the voltage is on most of the time (top graph) At low speed the voltage is on for a small percentage of the time Each drawing shows about 4 cycles & IIRC the frequency is in the low kHz range At low speed the motor gets a small kick each cycle, as these kicks are in the kHz range the motor looks to be rotating smoothly Some of the energy is lost in this jerky motion & is dissipated as sound My explanation may not be 100% correct but should give an insight into where the sound is coming from John

Maybe One way to check the black connection would be to check the DC voltage after the rectifier (4 diodes) Place your Multi-meter (set to DC Volts) on the PCB pads (between the diodes) marked (+) & (-) & you should get a reading between 10V & 18V depending on your DCC system The blue wire is also connected to the (+) & is an alternate place to put your Multi-meter (+) probe Don't confuse the Red & Black lines I added as (+) & (-) , they are the DCC in from the rails As has been stated previously "red & black to the track" Red is to the RH rail John

It looks like the printed circuit pad for the black wire from the decoder may have been damaged The violet wire ( J1) while it is not connected to anything is usually one of the function outputs (like the white & yellow wires) & could be used to control another light (cab interior light for example) Connecting the black wire to the violet wire could damage that function output If I am reading the decoder layout correctly then the red wire (right-hand rail) connects to 2 diodes (half of a bridge rectifier) see the red line I have added The black wire (left-hand rail) connects to 2 diodes (other half of the bridge rectifier(black line)) The black & violet wires shouldn't connect. Normally they would be connected to pads J2 & J1 which are on opposite sides of the PCB (Printed Circuit Board) & shouldn't be connecter to each other. If the PCB pad for the black wire is damaged or missing then connecting the black wire to the end of either diode indicated by the arrows should do the same job Hope this helps John

If you use a DMM for fault finding I would read the voltage at the Booster/command station with the layout disconnected Use this reading as a reference reconnect the layout & measure the voltages around the layout If you get any readings significantly less than the reference reading then there is something to investigate For anyone interested the drawing shows Voltage against Time for AC DCC & DC (Blue line is 0V) I believe the times shown on the DCC graph are correct The DCC wave form looks to be a square wave with the pulse width modulated to give the information for 1bit Wave Width of 100µs then bit = 0 Wave Width of 58µs then bit = 1 John PS can you spot the hitchhikers Easter egg

My understanding is the set at Crewe is as follows. I have also included the second N-DM they now have. If you want to make the surviving set with the correct numbers then you will need to do some renumbering and/or paint the nose window surrounds black If you start with the 5 Car set R3873 you get 1 DTS & 1 TBF with the correct numbers but the nose window surround is not black If you start with the 7 car set R3874 you get 1 TBF & 1 N-DM with the correct numbers. The DTS's have the correct black window surrounds but the incorrect numbers If you start with the 7 car set 2 DTS,s & 1 TBF will need to be renumbered There will be a N-DM & a APT-U left over The TRBS R40012 is a 2 coach pack (One coach is not used ) If you are comfortable painting the front window surrounds black & doing some renumbering then the 5 car set would be the cheapest place to start If you don't want to paint the front windows black & you don't mind the coach numbers being wrong then the 7 car set would be the better starting point Hope this helps John

Using a decoder like the ESU one shown(on the left) can give a fairly easy install(this ESU is a Next18 decoder plugged into a mother board) They are fairly thin & may fit under the roof above the seats With this format of decoder there is no need for a circuit board (similar format decoders should be available from other manufactures) ESU also make a MTC21 adaptor board (on the right) if you want to go down the 21pin decoder path The advantage with both of these boards is easy replacement of a failed decoder The 2 images are not to the same scale John

Depending on how the rest of your layout is configured you may not need any reversing sections I have added a little extra track to your drawing & shown the rail polarities in at the affected crossings I've added red & black dots to represent rail polarity You will need to sort the crossing polarity as you have already considered The crossing I have marked as X2 I would probably control with P5 or you could use a frogjuicer With P5 & P3 set to the main line the X2 needs to be the polarity shown Setting P3 to the terminus requires no change to the crossing polarity (X2) Setting P5 to the terminus requires the polarity of X2 rails to reverse polarity (not the frogs) (no trains should cross the crossing (X2) to of from P3 while P5 is set to the terminus as the polarity of X2 is incorrect & you risk a collision) The more complex problem is the terminus The crossing (X1) could be controlled as shown Or the contacts P1a & P1b could be a relay controlled by Point P1 or P1a &p1b could be replaced with a frog juicer If tracks A or C join B then polarity reversals are required, this can be done as shown at P2 After first drawing P2 it occurred to me that contacts controlling P2's frog aren't necessary(hence the extra P2 shown without the frog switch) Hope this all makes sense John

Looking at your pictures I think you got the power bogie facing the wrong direction Have you removed the bower bogie from its side frame & replaced it in the wrong direction ? Here is a couple of pics to help show the correct orientation of the bogies This drawing shows which side the gears are on Looking forwards the gears on the power bogie are on the left side whereas on yours the gears look to be on the RH side John

Here are a couple of images that show where the decoder wires should go. (for those, like me who work better with images) The wires marked Motor (+) & Motor(-) refer to the brush terminals The following pic is to show the connection of the black wire (from the decoder) to the frame of the motor The frame or the motor is the LH (left hand) rail As mentioned earlier by Andyman7 If you removed the wheels from the dummy bogie it is important that they go back the correct way, with the geared wheels on the same side as each other But on the opposite side to the power bogie A couple of things that might be worth trying Try running it on DC with the decoder installed. if it runs then the decoder might be OK Try resetting the decoder, CV8 set to 8 works on some decoders If this works then the loco should run on address 3 You could also try setting CV29 to 6 & CV1 To 3 If this works then the loco should run on address 3 John

Try R769 Have a look here, it might give you some insight https://www.worthpoint.com/worthopedia/triang-Hornby-r769-class-47-robin-238646825 John

It would appear that you have crossed 2 wires Hopefully the drawings will reveal all If I have followed the wires correctly The Black wire at the power bogie end connects to the Decoder grey which is the motor (-) (currently incorrectly connected to the Chassis) One of the brown wires at the power bogie end connects to the Decoder orange which is the motor (+) The other brown wire at the power bogie end connects to the Decoder black which is the LH track pickup (currently incorrectly to the motor) The Black wire from the unpowered bogie connects to the decoder red which is the RH track pickup John

As a retired electrician my knowledge of electronics is limited I have added a local CDU to the drawing as I understand your description If you provide local CDU feed & return busses then the local return & feed busses only need to carry the firing current to the points on that bus & Then the Main return & feed busses only need to carry the charging current to the CDU's I feel that a change to the circuit might be doable* With the changed circuit I don't thing the resistance of the point motors comes into the equation The value or the resistor needs to be enough to turn the Darlington pair fully on By moving the transistor to it new location you could control it with an Arduino or similar Adding a opto-isolator** electrically isolates the control circuit from the point circuits & protects the control circuit **Someone smarter than me can tell me if I got the opto-isolator circuit correct *& if the new position of the Darlington pair will work John

I agree with Brian & that is how my mimic panel is configured The drawing shows 2 ways to wire LEDs The RH circuit should do what you ask. But I don't know how the relays (12V coil) will preform at half wave DC derived from DCC Having a relay across the DCC may interfere with the DCC signal Every point (relay) will add load to the DCC system The extra cost of relays It would be possible to add an opto-isolator between the DCC & the relay More cost & complexity The resistor for the LED can be between 1K & 10K depending on how bright you want the LED John

Here is a couple of ways to get a vertical transition The longer the transition the better, I would think 600mm should be ok The transitions in the drawings are exaggerated John

A simple (I hope) explanation of VA (Volt Amps) Power is calculate using P=I*V Where P = power in Watts, I = Current in Amps & V = Volts The A in VA refers to amps or current so I = A If you substitute A for I in P=I*V you get P=A*V Which looks as if Power = VA In a DC circuit P does = VA but Power (in Watts) not VA is the term(usually) used in DC circuits In an AC circuit Power only equals VA when the PF (Power Factor) equals 1 PF will equal 1 when the load is resistive With an inductive or capacitive load, the PF will no longer be 1 The VA will no longer equal the power (in Watts) (after this it gets more complex & there so many formulas I’ve forgotten) When selecting a power supply for model railways you need to know 5 things 1 is it safe. Approved for use in your country 2 is the primary voltage correct for your country 3 is the output AC or DC 4 what is the secondary voltage you need 5 what is the maximum current you are likely to draw Scoobydoo was given 3 bits of information 1 A VA rating (not really needed as it can be calculated from VA=V*A) 2 a voltage i.e. 16-24VAC 3 a current of 2A (16V at 2A = 32VA & 24V at 2A = 48VA) When you go searching you should only need the output voltage & current Another consideration is do you want a transformer or a power supply The difference is a transformer is one of the components in a power supply John Ps in your 2nd post the transformer is the second link can kill you if it is not installed properly

The only thing I can add to what Olddudders said is, if you run into problems ask more questions I (& I suspect many others) work better with images so photos of the dismantled loco would be helpful John

You could have a Micro switch under one end of the bridge that only closes when the bridge is in Another possibility is to have some sort of mechanical barrier that lifts & blocks the tracks when the bridge is removed If you plan to use slow motion point motors like Tortoise's then they could be arranged so that they set to the mainline when the bridge is lifted You would need a micro switch interlocked to the bridge A relay or relays with up to 4 C/O contacts & if you wanted to depower the track then 2 more NO contacts are needed John

No The motor wires on the decoder go to the motor I tend to work better with pictures so this should help The numbers are for a 6 pin decoder

Yes, for a loco with no lights. Lighting adds a bit to the complexity Probably Yes & they give off less heat. I've seen loco roofs distorted from the heat of a light bulb John

Out of the box Unifrog points need no modification There are bridges under the point to link all the RH rails(see yellow arrows) together & all the LH rails together (red arrows) There is a wire from the frog, green arrow indicates its end If left disconnected there is about 25mm of dead track at the frog Depending on what locos that you run through the point you may not need to power the frog With an unpowered frog 0-4-0 & other short wheelbase locos could stall The frog could be powered with a switch interlocked with the point blades or a frog juicer as Sol said John

The drawing should be self explanatory The cobalt on the left is powered by the accessory bus & the frog is powered by the track bus. This is the preferred option The cobalt on the right & the frog are both powered by the track bus command John PS RFS & John P answered while I was drawing, as for the gaugemaster's I don't know

A slight variation of Nigelcliffe's idea I have only drawn the relevant parts of the layout The DPDT contacts can be a switch or relay interlocked with point 1 The green section is only connected to the AR(auto reverse) module when Point 1 is set to curved If suitable, by moving point 2 as shown you get a slightly better flow into the storage yard by eliminating an "S" curve & the brown section becomes long enough to park a loco or DMU. John

If I understand you correctly then this should work Wiring for a 2 aspect signal with a common cathode is shown If your signal is common anode then the LEDs become diodes & the diodes become LEDs The diodes are there to limit the reverse voltage across the LEDs to a safe level John

This is the first post by in a topic titled Which Switch(es)? From March 2018 followed by a couple of the replies that might be of interest John