PeteB

The Gaugemaster DCC27 is a 4 function decoder - so that's front and rear marker lights, and 2xcab lights. The headcode is on the next function output, which your decoder doesn't have. You could rewire the board, perhaps put both cab lights on the same function output and the headcode on the wire that becomes available by so doing. I am also using the MERG DCC handsets, see my post http://www.rmweb.co.uk/community/index.php?/topic/88264-oo-gauge-class-71-electric-locomotive/?view=findpost&p=2731227 for how I tweaked the circuit board to get all the functions with a Zimo 6 function decoder.

Hi Dave, I got two invoices, 0347 for the two Class 92s I ordered, and also 0427 for just one of them. I paid 0347 for the two locos, but not 0427 which is an error (probably my finger trouble when I was trying to order the two). So if you still have 0427 on your books, please could you cancel it and just keep 0347 for the two. Another question - will you be using the same motor arrangement as the class 71 and, if so, will you be addressing the maximum speed issue? No a problem for me, my GBRF and EWS ones will be mainly on freight, so not going fast, but for those modelling the Caledonian Sleeper, AIUI, it normally operates up to 80mph but can go up to the loco/stock maximum (87mph for Class 92) if running more than 20 mins late. Thanks, Pete

So the Class 71's had the booster to get them across gaps, and to restart if they came to a stop whilst gapped, the class 73's and 74's generally coasted the gaps, but could start the diesel if they stopped whilst gapped, and could use it in areas with lots of known gaps, and I guess EMU's have lots more collection shoes wider spaced, but how do the class 92's cope when running on 3rd rail?

Presumably you will have a bit less to do for the chassis this time round - all the internals, motor, drive chain etc should be the same as the class 71. Will you be able to just produce more of the same class 71 chassis unit from the factory for the class 74? I just pulled this out of my drawer - I wonder if I should try and build it before the DJM ones arrive? I have little doubt the DJM one will somewhat overshadow it! Pete

Well, I took the plunge and got it sorted. A few minutes with the meter sussed out what was occurring with the headcode lights on the DJM circuit board - it is indeed wired for logic level output on this one. This pic shows the transistor that is used to covert the logic level output from aux 3 (or FO3 in Zimo terminology) to drive the LED. As the Zimo FO3 output is a standard function output, we don't want it going through the transistor. Fortunately, the FO3 output on the decoder socket is connected to the transistor by a resistor and the transistor is connected to the LED and its series resistor by a zero ohm link, so by removing these the function output and LED connection are now isolated. This can be done without any scalpel surgery to the PCB, so they could always be refitted later if required: And here it is with the two components removed. Interestingly, the zero ohm link is identified as D1, indicating a diode, and underneath there is diode symbol, but it is definitely a zero ohm link. . Now the FO3 output and the LED (with its series resistor) are isolated from everything else, all I had to do was join them together with a wire link: And hey presto - we now have working headcodes: The headcode was over-bright to start with, but I have dimmed it, and the cab lights, using the decoder settings so now it looks much better. I also set the cab lights so, if you have them turned on, they go off automatically when the loco starts moving. I can post Decoder Pro screenshots if anyone wants to know how to do those settings in a Zimo decoder. Since I also have AUX4/FO4 available on this decoder, the next step will be to separate one end from FO3 and connect it to FO4 instead, so each end can operate independently, and then make them operate directionally. I think I will have to lift up the DJM decoder and cut a track to achieve this, because I think the track linking the headcodes at both ends is under the PCB. I will also have to add a resistor for the other end, and probably change the value of the resistor which will now only feed one LED. I can post details of those changes if/when I get around to it, if anyone is interested. Pete

Great news - good to know great minds think alike! Hopefully they will also be able to link to it from their home page and the limited editions page, to maximise exposure. Lets hope that 25% turns into 100% soon!

I agree - the class 74 is actually pretty well hidden on the Kernow website - to the extent that, until Dave' adverts hit the doormats, probably the only people who know about it are those following this forum. If you go to the Kernow home page, it is not mentioned anywhere. If you follow the link from the home page to limited editions: http://www.kernowmodelrailcentre.com/pg/110/Limited-Editions then the class 74 does not appear anywhere on that page - although the D600 warship and class 71 are there. To find the Class 74 you have to follow the class 71 link and then scroll all the way down to the bottom, where it appears rather like an afterthought. What would be much better (and I do realise that Kernow may have other marketing priorities) would be if the class 74 could have its own page, as already suggested, and have a link to it from that feature box at the top of the home page, as well as referenced from the limited editions page. Wording such as "Following on from the success of the DJM Class 71....."! would be good. I think it would also be a good idea to make it clear in the blurb about the Class 74 that it was an electro-diesel, so totally realistic to run it without a 3rd rail. Some might have not bought a Class 71 because it doesn't look right without a 3rd rail present, so they might order a class 74 if they realise it didn't always need one, when the diesel engine wasn't on fire... (no, no! don't put that last bit in!) The magazines always seem to publish progress on new projects, so I guess an update on Class 74 progress (ie: Class 71 now delivered, Class 74 now awaiting sufficient crowdfunding orders) might be of interest to the magazine editors. The update could include a link to the Kernow website, but the class 74 page on their needs sorting out first. Just my two-penneth! I want this to happen as I really want a Class 74 (actually I have ordered two). Regards, Pete

I was surprised about that - I don't see how changing a CV could re-wire the function output of the decoder. Reading the Zimo manual, which is, of course, a translation of the German, I suspect (although this is a guess) that what it means is that with an MX634C you need CV8=3 and with an MX634D you need CV8=4 for it to work correctly - more to do with output polarity from the microcontroller than the actual wiring of the output on those two decoder variants. Looking closely at the Lenz docs, the 5 function Silver decoder is described as "4 functions 100mA, total 400mA function current". So although it doesn't actually say so, the implication is that function 5 is not included in that, so presumably a logic level output. I spoke to somebody who knows, and he confirmed this, the fifth function output on a Lenz Silver is logic level. He told me that there are conflicting statements in different NMRA spec documents, one saying that function outputs above 4 can be logic level, the other saying that they should all be proper function outputs. So it depends which document you read. Seems that ESU, Lenz and DJM have gone for logic level, whilst Zimo have gone for full outputs. All of which means that to use function outputs 5 and 6 (aux3/aux4 or FO3/FO4) from the Zimo on the DJM Class 71, some wiring changes will be needed.

Don't forget that the Class 71 pantograph was only ever used in yards and sidings, at very slow speed, as that is where the overhead wires were installed to avoid the danger to staff of the 3rd rail. It was 660/750V DC - not the 25KV AC of modern overhead wires. This means that, even if you go to the trouble of installing the wires in your yards, you would only be using the pantograph at shunting speeds, once the class 71 leaves the yard onto the main line, it would be on third rail, so I suspect that the durability of the pantograph when used under the wires is not such a big issue.

Good point - no they don't work on mine at a the moment. Looking at the decoder manuals, the ESU Loksound Aux3 and Aux4 are only logic level outputs, whereas on the Zimo 634D they are normal full function outputs like the other function wires. So it seems likely that Dave was thinking of the Loksound and has wired it to work from logic level outputs - which is why it is not working with the Zimo. It will probably need attacking the circuit board with scalpel and soldering iron to get the desired behaviour. I was thinking of splitting the two headcode displays so they could be turned on and off independently anyway, since we have aux4 available as another function output. I'll let you know when I have worked out what needs doing. Regards, Pete

Ok, done some experimenting now. I measured my track voltage as about 13.8V on the track with an AC voltmeter (not so accurate) and 14.0 V in the booster drive to the output FETs with the meter on DC (more accurate). So fairly low by normal DCC standards. I measured out a 2.1m length on the layout, which is 1/10th mile in 4mm scale (2112mm to be precise) and timed the class 71 over this - averaged in both directions and with the loco on the track either way round to remove any slight gradient or variations in performance in either direction from the calculation. It averaged just over 7 secs, which comes out at 51 mph. I then adjusted the voltage in the booster, to give 15.8V on the track (16V measured at the booster FET drive). It did make a difference, it now averaged 5.9 seconds giving 61 mph. Playing with CV 57, which sets the max voltage to the motor, didn't make any difference, so the default of zero (which means auto), is presumably giving the best performance anyway. For me, that's quite sufficient for how fast I want to run my trains, but I could understand that if you want to model the Golden Arrow in full fight, it might be a bit on the low side. At this speed, the motor did sound to be thrashing quite hard, so I guess it must be quite low geared. I suppose that must be necessary to give the haulage power from such a small motor, but it seems that loss of top end speed is the compromise that results.

Fair enough, I've no doubt bif will be happy to advise in due course. However, I have made progress. I took the Zimo MX634D out of my Dapol Class 68 and put it into the Class 71, and much better running immediately just on the default settings - so Zimo 1 ESU nil for the class 71at that point. However as a bonus, putting the ESU decoder in the Class 68 has enabled me to map all the class 68 functions so they work sensibly (the Dapol wiring is strange!) - so ESU 1 Zimo nil in the class 68 for the clever ESU function mapping capabilities. I then refined the Zimo decoder settings in the class 71 using the CV values that RFS kindly posted and the slow running is now even better. Top speed would definitely be an issue for a main line layout where you want to run expresses - but I like to trundle my trains so not really an issue for me. When I get into implementing automation it might be a problem, speed step 55 is still crawling, so I might need to set a speed table that ramps the speed up initially at a rate similar to most other locos and then max's out when it hits the fastest the class 71 can do. I will try tweaking the track voltage up a bit (within NMRA DCC limits) to see if that makes a difference - I'll report back if it helps. Pete

Back on the 17th, tetsudofan (Keith) posted: Any chance of posting that list of CVs here? I have my lovely class 71 here, and I robbed an ESU decoder from another loco to get it running, but I am suffering from the jackrabbit at slow speed, and I havn't been able to find the right combination of motor CVs to get it running smoothly. Unusually the automatic motor setup on the ESU decoder didn't work for this one. If the settings could be posted here, that would help anyone struggling to set up an ESU decoder for this loco in the future. Thanks, Pete

Thanks to JJGraphics for the email address, I have now confirmed the order with Tom and sent the Paypal payment - looking forward to sorting out all those all plastic wheeled coaches!

It's a tool for reaming out the axle boxes so you can fit brass bearings. For me, I want to use it to replace the plastic wheelsets on old stock with metal ones to a more modern profile that run in proper bearings. As for how you use it - if I can get hold of one then I shall be able to read the instructions! Has anybody on here been able to buy one? I've had no response from Tom to PM or post on here, although his profile indicates he was last active on 14th August. His original post says he is sorting out a website, but no URL is given and I can't find anything on Google search. The EM society list it, but the entry says "no stock". Seems a great idea, if only it was obtainable. Regards, Pete

Hi Tom, I'd like to get one of your brass bearing tools. I did send a PM but I wonder if you got it, as I have had no reply. Let me know how I can pay you (online transfer, Paypal?) and I'll get the payment to you. Thanks, Pete

Aha - I had indeed missed that little sentence deep in the web page - my apologies. Great news that the project is progressing. It would also be great if, when they are ready, Kernow could post the latest CAD iterations here so that the various experts on RMweb can help with feedback, as happens with the DJM own brand models. Looking forward to seeing this one come to fruition.....

I wonder if Kernow and/or DJM might give us some sort of update as to the progress on this project? Is it still alive? I've just searched the Kernow website and also gone back on the Kernow Facebook page for over a year and I can find no mention of it. I have now subscribed to the Kernow newsletter as suggested above - but there seems to be no way to look at back issues so I may have missed some announcements - can anyone who gets this newsletter comment what the latest news is for those of us who may have missed it? I understand that DJM are now doing this for Kernow - and I see lots of news about new DJM projects for class 86 and 87 as well as great progress on class 71 and 74, but the poor old D6xx Warship seems to have been left out in the cold. I understand the reasons for the delays, but just to keep all of us who have placed orders (and others who might be tempted to do so) interested, it would be nice to see some updates on progress from time to time, like we do for other Kernow projects such as the new TC set.

Well, I guess I am quite rare, but I'm actually quite pleased with my Class 73. I have Brighton Evening Argus from Gaugemaster. I collected it in person from Gaugemaster as I was down that way. I'm afraid I've forgotten the name of who served me, but he was very helpful and quite happy for me to take it out of the box to check for any dropped off parts, buffers pointing in strange directions etc. We also put it on their test track where it ran nicely, I picked up each bogie in turn to check it was picking up from both (a friend had a green one that only picked up from one bogie). I then put the Micrometer on the wheels and confirmed that the back to backs and flange widths are all compliant with NMRA/DOGA etc (DJM please note!). It all looked good at the shop, so I bought it. Once back home, switching a circuit of the layout to DC, it runs very nicely through both Peco code 100 and my 00-SF trackwork, no hesitating on the points and very smooth running. It will get a sound decoder in due course. Yes, the couplings were assembled upside down, but forewarned by this forum that was an easy fix. Yes, the cab lights are on all the time but a scalpel and soldering iron will soon see them operating from spare functions on the decoder, when fitted. The yellow end is a bit lemony, but to my untrained eye this is less noticeable on the Pullman livery and it can always be airbrushed if I feel the urge. I'm happy with the Pullman livery, because it looks fine to me and I don't actually know exactly what shade of brown it should be and I won't get involved in that discussion. So, overall, I'm a happy customer. That said, I have postponed buying a blue one until that livery is sorted out - the purple shade is too noticeable and the yellow ends are much more noticeably the wrong colour as it will be parked next to Hornby/Heljan/Bachmann in the same livery, which doesn't apply to 73101. Regards, Pete

For that to have any chance of happening, the retailers first have to give feedback to Dapol. I spoke to Gaugemaster yesterday about my pre-order for the Pullman 73, and I was told that Gaugemaster was not aware of any problems with any of the Dapol class 73's !! Is that really possible?

To answer my own question, the answer is YES! Due to the deafening silence in response to my question on here, I phoned Kernow and the helpful gentleman who answered went and found out for me. I was told that if you have one Class 71 on order, then you can have the £20 discount off more than one class 74, as long as you honour the order for the class 71. So I shall be ordering two class 74s shortly.

I visited the Gaugemaster shop in Ford yesterday, and I spotted the preproduction samples of their limited edition Pullman livery class 73s. I asked if they minded me taking a few pics and posting them here, so with their permission here they are. Sorry about the less than perfect photos and the reflections, I only had the mobile phone with me. Regards, Pete

Rats! I was at Peterborough but I only just caught up with this thread, so I didn't know to look and I didn't see it. Note to self: I must keep up wth developments on RMweb. Is it just me, or do those wheels look a little coarse in the front view? Are these the wheels that will be fitted to production models? If you still have that sample, it would be really useful if you could take a micrometer to it and let us know the back to back measrement and flange widths. According to S-4.2, for RP25/110 wheels, back to back should be 14.55mm plus 0.05 minus 0.18, the flange thickness should be no greater than 0.76mm and the tread width no greater than 2mm. My concern is because I still have the problem that my Well Tank derails on my 00-SF track, due to flanges that are a bit wider than the above, and back to back set much wider, putting it over-gauge on my pointwork. I spoke to Dave at the Barrow Hill show and he assured me that the spec to the factory is 14.4mm back to back. Kernow kindly let me measure anohter example on their stand and it was the same as mine. At some point I will pluck up courage to take it apart and try to adjust the back to back, but it would be good if I don't have to do that on future models. I note that the Model Rail review of the new Adams O2 measures the back to back as 15mm, and report some binding on curves, so if there is a problem with the factory setting the wheelsets up correctly, it would be good to catch it now on this new model.

Great news - this the one I am waiting for. I have one class 71 on order, if I were to order two Class 74's would I get the extra £20 discount on both of them?

Thanks Dave, I wondered if that was the case. I'll make sure my order goes via Kernow as I want the money to help with funding the project. What I really want is a class 74, so my plan is to order a class 71 to help with the project, then as soon as a class 74 is available to pre-order or crowd fund, then I'll sell the class 71 and put the money towards a class 74. I wonder if you might sell more class 74s in the long run, as it is much easier to think of an excuse under rule 1 to run a class 74 as at least they can realistically run away from the third rail - whereas a real class 71 would be unable to move unless a third rail is present, which many (most?) don't have on their layout. However, I can see the logic of doing the class 71 first, as at least one still exists for you to scan. Regards, Pete