dmsmith

I’m sorry that it has taken me some time to reply, but I’d wanted to check the diameter of the wheels that I had first used. Those were 12.3 mm diameter at their smallest, but whilst I thought they were Gibsons, there was a chance they might be original Kean Maygibs. I therefore tried some Gibson’s from a branded packet: 12.3 mm at their smallest. Maybe the variation in diameter between wheels is that much. Your advice to measure therefore seems very wise. That 0.3 mm seems to make all the difference. It is because the Accurascale brake blocks are admirably close to the wheels. Thanks for your advice! David

I’ve actually gone rather crazy on 21-ton minerals. I started last year by cutting down the bodies of some 24 1/2-ton Parkside bodies and using Rumney models underframes. But then Chivers brought out their kit. That includes moulded headstocks and reasonable underframe mouldings, so I used some Masokits foldup sprung chassis. I then thought that I might as well try the Accurascale way. Most enjoyment? Definitely the Parkside/Rumney versions. The Rumney chassis gives excellent results. Quickest? The Accurascale, although sourcing 12.0 mm wheels should be an unnecessary faff. i’m not sure why I started on the project. Maybe because I’ve not long moved to Swansea, and work not far from the Burrows yard. I’ll post some pictures at some point when I’ve finished them. Thanks for your advice and encouragement! David

Thank you! I have invested in both a set of unfitted and fitted wagons from the new batch. I’m halfway through converting the unfitted wagons. So far, no problems. I gently removed the safety loops, released the brake gear from the chassis frame, and eased out the cross shaft from the brake vees. I did reduce the depth of the socket for the cross shaft slightly so that when I reassembled with the brake gear in the alternative locating holes that Accurascale provide for EM and P4, it sat slightly better. But, most importantly, I too used 12.0 mm diameter wheels. Mine were Kean Maygib DMU wheels. No holes, but not noticeable. The Accurascale wheels are slightly undersize—about 12.2 mm diameter at their smallest. I will try to turn down the original wheels once I get my lathe set up. I haven’t tried them on a layout. I’ll report back once I’ve moved on to the MDWs. Best wishes David

I’d be interested to know whether anyone has converted this latest batch of either unfitted MDOs or vacuum-fitted MDVs to EM or P4. I was put off the first batch by stories that it wasn’t at all straightforward, which missed the point of buying RTR rather than building a kit. But there was a suggestion that the issues would be addressed in this new batch … Best wishes David

Thank you Steve!

I’d be interested in the etches, even at that price, to produce a cameo where I might take photographs. Do you have a link or other contact details for who produced them? Best wishes David

Thank you! I was asking because I couldn’t see a way to remove them without causing damage. You’ve reaffirmed my original view, although I’m sorry that you had to find out the hard way. Best wishes David

Thanks Liam, for such an informative post. I’m looking to convert mine to P4, so you’ve given me a head start. I notice that you’ve removed the brake gear. Others have suggested chamfering the back of the brake shoes for EM or P4. Are you planning to reposition the brake hangers and shoes? If so, are the yokes wide enough? Best wishes David

Thank you all once again for your suggestions. I polished the wheel flanges carefully, as suggested, which made a small improvement, but the Zen decoder still kept shutting down. I’m more convinced than ever that the contact between wire pickup and flange is sending spurious signals to the decoder which interprets as commands. So, I followed the next suggestion and invested in a Zimo decoder and Lais stay alive from Digitrains, which came 24 hours after ordering. Problem solved! The running is now exceptional and the stay alive does everything that it should. I opted to stick with a 6-pin decoder because I’d already fitted the socket on the loco and fed it through a small hole in the cab floor. I was reasonably confident of my ability to solder the capacitor wires to the chip, and managed it without any problems. However, I can certainly see the appeal of the much bigger solder pads on the 18-pin socket. Now to see if the same solution works with my Judith Edge NBL 0-4-0 … Best wishes David

Thank you all for your suggestions. My assumption had been that the decoder is resetting if there is a momentary interruption in power from the pick ups. I was just surprised that there isn’t any hesitancy on DC. I did check the resistance between track, via wheels and pickups, to the decoder socket, and did get a short. It is possible that the wheel flanges are pitted. I’ll try turning them smooth, but I am nervous about removing them from the axle too many times. they are Alan Gibsons, and they don’t take kindly to being taken on and off. I’ll let you all know how I get on. Perhaps I am expecting too much of the Zen small stay alive. The DCC Concepts website suggests a run-on distance of 150 mm, but that must depend on speed, and with a 108:1 gearbox, that’s just a crawl. Interestingly, I can’t find the capacitance listed on the website. There’s not much space in the cab, but I’ll look at the Zimo range and a bigger socket. Best wishes David

Yes, Oldddudders! It was CV2 that I adjusted. I didn’t tinker with CV3.

Thanks for the suggestion, Ray! Unfortunately, that was one of the first things that I tried. It didn’t seem to make any difference at all! It was after that test that I installed the direct connection from the decoder socket to the track feed to bypass the pickups. The loco then works faultlessly, even with a CV3 setting of 0. It’s really strange! David

When I built the loco, I installed a 6 pin socket with connections to the pickups and the motor. To try to diagnose the problem, I’ve made a short harness with a 6-pin plug at one end and another socket at the other that I can insert between the old socket and the decoder. The wires to the motor run straight through, but I’ve attained some fly leads so that the power now runs straight from the new decoder socket and can be connected directly to the track to bypass the pick ups. Thanks for your thoughts! David

I have built a Craftsman 02 0-4-0 diesel shunter with a High Level 108:1 gear box and Mashima motor. The pick ups are phosphor bronze wire bearing on each of the wheel flanges. The loco runs well on DC with a blanking plug. However, I can’t get it to work with DCC. The motor turns a few revolutions and then stops. Given a nudge, the motor turns again, but for a few more revolutions. After each nudge, the motor runs for longer until eventually it turns continuously. I installed an NEM651 6-pin socket, so that I could swap decoders and blanking plugs. I’ve tried several different types of decoder, but to no avail. My most recent experiments have been with a Zen Blue+ (DCD-ZN6D.2). To eliminate one variable, I hard wired in the track feed to the decoder socket. The loco then runs perfectly on DCC … better than DC. That makes me think that it can’t be a problem of excessive current draw and makes me suspect the pick ups. I therefore invested in a Zen small stay alive, (DCD-SA3-SM.1). That seems to help a bit, but the loco is still unusable. I've tried the logical things like deactivating DC and back EMF. There is no suggestion of a short across the pickups. I’ve cleaned the track and wheels meticulously. Does anyone have any ideas? I’d be very grateful for your help. Best wishes David

Thank you @Nigelcliffe. I wasn’t aware of your webpage, which is a very useful resource. I’ve learnt a lot! Resetting CV29 to 28 steps did indeed resolve the speed step issue. Unfortunately, the directional problem remains. I’ll keep playing! Best wishes David