O-Gauge-Phil

Hi Just had another go. Yes four chuffs per rev. This time I did it back to front, set step 1 then step 10 -30 then backwards and forwards. step 1 ended up at 254 and I could do with a bit more because it still gains on it. If you don't look carefully it now sounds about right. Zimo sound is very good, nice loud chuffs! (not necessary in the right order). Also can anyone recommend a flag / sensor that can easily be retro fitted onto 3/16 axle. Thanks for the help I don't think I could have got there on my own. Phil

You are correct and as Richard said in a domestic environment you have a set speakers, one for the high notes, one for the low notes and sometimes one for the midrange. You also have some electrical / electronic bits to route the signals to the relevant speaker. In O gauge you sometimes have the space for more than one speaker, then you can just double them up to get more or better sound quality (two small speakers will have less momentum). What I do is use a large speaker/s for the normal sound but pass the signal also through a capacitor to filter out the low frequency and use one or two small diameter but powerful speakers for the midrange and high frequencys, efficiently extending the frequency response. This time I was being a bit lazy because the ESU V5 come with a speaker. Their is also something called the maximum power transfer theorem, this is why you have to have 4 ohms on some 100 on others. By passing through a capacitor the resistance is so high it does not have to be included when calculating the total resistance eg 2 x 4 ohms in series -> 8ohms. I have now built and tested and the speaker diagram above was correct. As an aside and as a little tip I used Maskol to insulate the terminals on the little speaker. Phil

Well set cv9 -> 0 and cv56 -> 0 Chuffs speed step 10 cv267 adjusted to 31 ok , then cv 354 increased value even more chuffs, on zero still getting 6.5 chuffs per rev increase cv354 to a nominal 20, went back to 267 trimmed that again -> 50, then back to 354 trimmed to 21. Now ok step 1, ok step 10 , step 100 8 chuffs per rev , this is just the same as when I hadn't set the feedback correctly. Loco is a 7mm scale Dukedog, so quite large wheels. Do the numbers I'm entering seem what you would of expected? What should I try next, feel quite exhausted. Phil

Thanks for that, it really didn’t come out in the manual, the manual isn’t a light read but when I get time I’ll try and read it over and over again. Do you think Zimos are worth persevering with? With ESU I give it ten revs divide time by 40 enter as a time . Anyway thanks again for your quick and I will try again in a moment.

Hi How to set Zimo 645 decoder up. I am sure it's been covered plenty of times in the past but my search hasn't turned anything useful, so I would be grateful for a link or suggestions. I have a Zimo 645 connected to an RG7 with a coreless motor. I'm using JMRI to program it. I've previously set seven or eight Loksound decoders up with no problem but nothing I do to the motor settings seems to make much difference. cv 9 -> 12 cv56 -> it said add 100 for coreless I've tried 100, 111 and 133 all seem to be much of a muchness , motor sounds a bit labouring test run 302 -> 75 don't have 302 on JMRI , do I really need 5 meters of track? Set chuffs up on step 10 double chuffs when small increase in speed. I'm sure it's straightforward when you have done a few and it's not helped as I'm rushing to get things ready for an exhibition but isn't there a self tune button like on ESU. Thanks in advance Phil

Just wired in a new decoder. The EM2 above is faulty, the programmer kept tripping and I tracked it down to the speaker. So I must apologise to the EM2 it’s probably much better than I thought.

The photo of the EM2 was in answer to Richard. It’s probably good in a diesel but in a steam engine it doesn’t have that bark. Not enough surface area me thinks. I built a home made speaker last week with a fairly ordinary oval loudspeaker in a large enclosure and it knocked the socks off this. Still it’s all in the ears of the beholder. Phil

Thought I didn’t make myself clear, it was the little loksound speaker I was after details of, however I think I’ve found details by googling iPhone speaker. I am intending to add an iPhone type speaker between the frames of the loco. Anyway I’ll add what I’ve found here. On the top diagram the speaker is upside down and the spring clips added, when they supply the same speaker with solder pads or leads the connections are the same as the bottom dia. When adding a second speaker it needs to be in phase.

Rewired the tender plug today, this engine had just the one speaker. When I first started converting my locos to Dcc I bought a selection of speaker, they have all gone now. I don’t think this one stood out particularly. Could not see any movement on the iPhone speaker when applying a voltage, no one has furnished a diagram and I must be googling the wrong words. It seems strange that I cannot find a diagram of this little blighter. Phil

Good job Tom. Should have a nice smooth engine and cleaner sound. I just looked up the price for the components, from a real about £0.00.09 plus a socket. How much do they spend replacing decoders under warranty? Who uses aux 3 & 4 or servos? compared to stay alive caps. It may not suit the budget end of the market but where you spend £100 this should be included, along with speeker contacts on the plug . Just got a Zimo MX 645 and that comes with leads and electronics. Also just got a V5 and that now comes with flighing leads and electronics on board the capacitor . Well done again Tom

Not quite sure on this one. I originally fitted a Zimo decoder but wasn't happy, so now I am fitting an ESU and improving the plug and socket to the tender. when I open the tender up this morning I'll have a look. I usually use speekers from dc kits or troll through RS etc looking for something with a good flat response, well I try anyway. I quite often build my own chambers to fit the loco. I use thick plasicard and if I remember some sound deadening foam inside. I probably make them to big but better that, sometimes long and thin , sometimes deep. What is your weapon of choice?

Thanks, yes i'm connecting it into a cross over network. I usually fit the biggest bass speeker/s I can in the tender and a couple of purpose made tweeters preferably in the loco under the chimney but on retro fits they have to go in the tender. The tweeter is coupled through a small capacitor. I did another loco on Thursday using again another esu speeker that came with the v5 but did that one by ear, it is quite noticeable. This time I thought it would be easiier to write down which way round it went for future reference . I think I have found it on a data sheet and I did know with plus to plus should by convention move forward, tomorrow I'll see if I can see movement. On an O gauge engine it would be criminal not to use the space. Thanks again for help and giving your time.

Does anyone know what way round the little speekers that now come as standard. I cannot see a plus or minus but I thought it would sit nicely between the frames as a tweeter? Thanks Phil

I really don't understand why manufacturers make it so difficult, to me stay alive is a basic requirement. Why not have the electronics on board and a micro plug and socket for the capacitor, simple next to no cost. Phil

Amassing pictures, full of character and so nice to see the first sod is cut. Phil

If the cabin wasn't enough that wagon looks like a lot of work . Nice simple kit too for your second wagon!! Still good job on the brake van, so I will follow with interest especially as it's one on my wish list when time permits. Best wishes for the weekend and hope the weather holds. Phil

As you have probably guessed anyone know who makes the transfers? Thanks Phil

Exciting times!

I see the radio has gone and the dcc is wired in. Was this an easy job, retro fitting droppers, frog switches? Phil

Hi are you close to Enfield? If so you could bring it to our club, we can help fix it and get you started in loco building or look up your local club, would think someone has the required knowledge. Phil

Surely this is something that someone like Modelu could do. It should be quite easy to custom make as you can reference the number to a grid on an Excel spreadsheet or some other data source. Phil

Yes, I would concur, 2.4 amps is high but not outrageous, as a standard size decoder can handle 15 to 20 amps stall current. Controllers have overloads built in because it wouldn't take that long to burn a motor out when stalled. Normally when running, due to the back emf this would probably restrict to 200-300 mA. One of my friends, who is a motor mechanic, used a windscreen washer motor, this ran okay for a minute or so before conking out because it was only designed for short runs. I have just measured a normal O gauge can motor and that was 77 ohms, all my other motors are coreless, so it does seem very low, something doesn't seem quite right. The radio controller you are replacing - what make and model was it? Because if this was okay working from the radio control, a decoder of a similar value shouldn't be a problem. One question I have is - is this a 12v motor or was it running off battery voltage, 4 or 8 volts? I'm off to the train club now, they have a Dapol loco so I'll measure that. Phil

No problem, move the black lead to the terminal marked "10A MAX". Then 1) connect one side of the motor to one terminal on your controller, then 2) connect the red cable to the controller's other terminal and 3) the black lead to the other side of the motor. Whilst holding the motor so it doesn't rotate, set the controller to MAX . The motor will now produce quite a lot of force so don't let it pinch your fingers in the gears. You should now be able to read the current with a stalled armiture. As soon as you have got a reading - no more than a second or two - disconnect the wires and let go of the motor. This will then be your stalled motor current. Personally I would not use this method because it is complicated and could potentially burn your motor out. My calculated method described previously is far easier, less risky and will give the same result As a caveat, decoders have a constant current and a short term rating. The continuous rating may be say 1.2 amps and the short term 15 or 25 amps for 20 seconds. The chip has an overload function. Therefore the short term rating is more than enough and the main criteria is how much current the motor will draw when it is pulling the biggest load. No eight coach trains on Tewkesbury! From Colin's observations the Canon motor would be quite happy with a 1.2 amp unit but the big beast may demand something a bit bigger. As your loco was battery powered it most likely doesn't take much current and after the removal of the radio, space shouldn't be a concern. Low current decoders cost about the same but are a lot smaller. Give the first method a go and let us know what you get. You can always send the supplier a picture, they should be able to work it out from past experience. Hope I've helped and not made it more complicated? Phil ps. Don't forget to move the 10 A leads back or you could burn your meter out if you go to test something with a voltage on it.

Set your meter to the lowest resistance range, on your meter this is 200. Then with the leads in their position as shown, ie. not in the 10 amp position, touch the two leads together and check that the resistance reading is zero. Now measure the resistance of the motor and if necessary subtract the value you have got when you touch the leads together. Then using ohms law calculate the maximum current. The voltage is set within the decoder, usually 12 volts, (however I normally set mine to 9 or 10 volts) eg. WIth a motor resistance of 100 ohms and 12 volts, then I = V / R = 12 / 100 = 120mA. This will give you the maximum current that can be drawn by that motor. As the motor rotates it will generate back emf which will reduce the current drawn. You don't usually see this level of current as you normally start on a reduced voltage. Modern motors don't as a rule draw much current and a one amp decoder is okay for most O gauge locomotives. I thought this might also be of interest to others. Phil

Yep that's right, probably in the khz range. If you set the brightness to full ie 100% on 0 off then the flickering should stop. Changing the resistance makes very little difference to the brightness but changing the on / off ratio has a direct relationship. Sorry cannot help with camera settings, just a black box to me. Phil