97403_Ixion

Hi Nick, Glad it is sorted for now! Keep an eye on whether the diode gets hot in anyway, which could indicate a partial short or similar. It may just be an under-rated diode (voltage-wise) in the design, so if it does fail again, I would have thought the 40V (reverse-bias) ones suggested should be suitable. I like that buffer-stop LED! The trouble with LED's these days is they are so bright, so putting a larger resistor inline should help quite easily. Alternatively, pulsing it rapidly with variable on-off times can yield the same effect but a lot more electronics is involved! The Network Rail transit van in my picture was not the Kytes Lights one but I do have a very similar sized one by them in yellow with the AA (Automobile Association) branding on it. It has yellow lights if I remember right but the real impressive ones are their fire engines and ambulances which have very well sequenced, high brightness flashed blue LED's, along with other lights where appropriate. How they get the wires in is a masterpiece of work without them showing but they are great in cameo scenes on a layout... the only downside is no sound (though it may be possible to modify the OO ones to fit it?!). Always glad to help people out... it's what forums like this do well... but I do appreciate your thanks Keep enjoying your modelling! Thanks, Ixion.

Those 33's are good, aren't they?! I like the layout - looking good! Ironically, I was adjusting a PCB symbol for a diode after a big design review today - funny how life is! You are right about the 500 likely being mV for a regular silicon diode (I could probably go into the maths but I would sound a bit... Sheldon like [Big Bang Theory TV programme]) If the Gaugemaster gives 12V, it's not very likely to be the culprit as you say... that sounds quite a good unit to me - will have to look them up. There is a remote possibility of damage due to Electro-Static Discharge (ESD), which could be down to poor static control... though most models are pretty robust - at least the DC ones! The grass in the photo does look rather good and I would guess it was applied using a static process? I'm not saying the grass would be a problem itself but I take it the models weren't out near the applicator when the unit was used? Since you have two failed PCB's, this probably rules this out... unless both got near the static at different times... clutching at straws already... Hmm, it's a puzzler! I've done a quick check of what I suspect may be a suitable diode. It's a schottky, rated at 40V, 500mA, so I would suspect it is more than capable of a few LED's... for which I am thinking the motor does not form part of the circuit beyond the diode bridge rectifier. The part is: PMEG4005AEA - link to RS Components (other suppliers also available!). It looks to be in a SOD-323 package (~1.7mm x 1.25mm), with small leads at either end. The pack size is 20 @ ~26p each, so plenty spare and not too expensive to try... Another possibility, would be to use a sacrificial diode from the spare PCB... at least this may get a quicker response. Though be careful to fit it the right way around, or it could blow it... Now, I'm not saying it will solve the fault that causes the problem but if it is inherent in an under-rated diode, then it could. It may also give you a chance to get the model up and running. There may be a fault or short elsewhere on the PCB, so don't despair if it fails again... If you can run the model with the bodyshell off, carefully touch the diode while running the 31 up and down a few times - if it gets hot, there is likely a short elsewhere which may need sorting too. If it runs cool (or luke warm) then it's probably OK. Now... my turn for a photo... These N gauge motor vehicle models by Oxford are great! I was blown away though when I saw one with lights fitted by Kytes Lights - so much so I had to buy it! I'll keep thinking of other possible causes for your model and let you know... I think I have a 31 in my collection but will need to track it down - I think it went into store in a large cardboard engine shed with other locos ...and no problem helping out - I'm not so good at getting my own layout up and running but I do like seeing other people's layouts at exhibitions and on here, so helping others out is always good. Cheers, Ixion.

Hi Nick, I've had a really long day with CAD problems on work stuff, so can't provide a good analysis today but regarding the 169, did it say 169 with the suffix 'mV' on the diode test? Diode tests are in volts (or millivolts), not ohms, so the reading of 169 may look a bit odd if misinterpreted. If so, this could well be right for a working diode (i.e. your D4 from your spare PCB) and suggests it is what they call a Schottky diode, which has a lower forward voltage than regular silicon diodes. This type is likely to be used to prevent voltage drop in a rectifier circuit which basically turns AC (such as a DCC powered rail) into DC... and with four diodes side-by-side, it looks like it could be what they call a full-wave rectifier. In DC mode (which I think is what you are using), the diodes work in the same manner but only one half of them conduct when running in one direction; the other pair in the opposite direction. I found another PCB photo online and it looks like the two feeds from the DCC connector's middle contacts are the Rail power and feed into this diode arrangement. This would be to create a DC supply of some sort - probably for the LED's/lights. Now, if diode D3 or even D1 were to fail short circuit (or low value), it would mean the track would be trying to drive the supply across the other, non-failed diode directly which would limit the voltage across the track... this tallies with you not getting movement in one direction as it effectively short circuits the motor's supply of power. In the other direction, the diode effectively conducts due to its shorting fault but as such, is acting like a more perfect diode - hence the track would not be short circuited and the motor would run. Hopefully that makes some sense?! I'm wondering if the switches control the rear lights? i.e. so light loco (front and rear lights) or train setting (front lights only) can be set - perhaps one switch for each end? So, the rear lights may not show when the model moves if the switch for that direction is in the wrong position. However, you would get no lights at all in one direction if the diode in the rectifier circuit has fused short circuit - but this only applies in one direction. All your comments do seem to suggest this. So.... the question is why did it fail? I hate to say it but production costs may be a cause - i.e. cheapest possible that does the job - not saying this is it but it could be a factor. A diode can fail through a few means - mainly over-current and over-voltage. It is probably unlikely that over-current is the cause, as the rectifier probably only supplies the LED's, which generally draw low amounts of current, though capacitors may exist which need charging rapidly and could cause a failure. However, another failure mode is over-voltage where the diode junction just cannot cope in reverse bias, so fails (breaks down in a non-recoverable way) and allows a current flow in either direction. This is a possibility! What kind of controller are you using? I have a Digitrax DCC controller and it has specific settings for N, OO and O gauge... though I would imagine DC controllers are not specifically rated for N or OO but more generic (I only have H&M or Bachmann's trainset controllers otherwise!). It is possible the diode ratings are a little near the mark and the controller is just a bit over the mark. Another possibility is a short has formed somewhere else - loose wire perhaps? As I say, it may take a little bit more thought to resolve your issue but what would be useful is to know the size of the diode - length and width. This will help identify the package type, though it looks like it may be what is called an 0805 (80 thou / 2mm by 50 thou / 1.25mm). This should help identify a diode that would be suitable. Rated to enough current and voltage with some margin should ensure it works properly for years to come! I must get some rest now (as I say, a long day but helping out is always a good thing!). I'll see if I can find anything more out in the meantime... but I suspect a badly rated type of diode or an over-voltage controller may be the cause. Cheers for now, Ixion.

Hi Nick / EMP, Firstly, welcome to the group! This is a good place to get advice from others as no doubt, someone will have had a similar issue at some point. A very useful place. I am not aware of the details of the PCB inside the 31 but I am an electronics engineer by profession, so may be able to advise... Did the loco once work but has now failed, taking out the PCB and also the spare PCB? i.e. did the fault occur after some previous use? I ask because zero ohms for a diode is not my normal experience of a failed diode. It sounds like there may be a short circuit somewhere else beyond the PCB. It's not likely, though not impossible, that both PCB's could have been faulty from the start... small components can become shorted between the pads underneath during the soldering process. However, I suspect this is not the case, or luck has not been favourable! I imagine to fit the spare PCB, you must have connected wires to the PCB somehow - are they all plug/socket connections? It sounds like you haven't soldered anything yet... If this is the case, can you remove the PCB, then re-check the diode resistance? Measure it in both direction too - there will often be a difference - it may even read open circuit one way around. If, having removed all the wires to the loco, the diode does not measure short circuit anymore, then clearly, there may be something in the loco itself. What may also be of help to me/us is a photo of the PCB... it may be possible to see the context of the diode with regards to other components on the PCB and/or connections to the loco. It may take a little time to work things out but I am sure it probably will be solvable. A new diode may be required, though there are a number of different types (power, current, forward voltage, etc.) but it most likely will not be necessary to source the exact same type - there are a myriad of manufacturers, all competing to sell their own! However, if the diode has failed, it's best to try to understand why, first. Let us know how you get on with the PCB isolated and if you can supply photos, that may help the diagnosis. Cheers, Ixion.

Could well be why! As much as I like certificates with numbers or knowing the production size for specials, given the circumstances for these models, the priority must be the charities the sales help. I cannot thank the NHS enough for what they have done for everyone over the year and continue to do so, so this did seem like a great way to help boost the funds for the charities and a route by which we all could help support them.

Just checked my OO model too - same here, no number on the certificate or box. I'll take a look at the N gauge one this evening, in case that is different. Interesting to note is the N-gauge image of the certificate doesn't have it, so maybe they changed their mind? N-gauge Pride of Britain Set Certificate (BCC) Have you or anyone asked BCC about it?

In case anyone wonders, the nameplates are not printed on the side of the OO model but are, as said above, included in a bag. There is also a bag of additional fittings and one bag each for the two aircraft, which includes a small stand and a label identifying each aircraft type with 'Pride of Britain' marked on it. I'm hoping to hang the aircraft above the layout to have them performing a flypast, perhaps above a cameo scene with Captain Tom doing his walk?!

I'm guessing the Captain Tom figure was your own? When I first looked I thought it was a bit like a cross between Nicholas Parsons (TV presenter) and Buzz Aldrin... then realised it was representing the good man himself! Nice touch though to have him next to the loco in your display cabinet!

Thanks to KR Models who got in touch earlier in the week and arranged the delivery, apologising for the delays. Pleased to say the model arrived today, though yet to get it fully out to take a look but generally looks good and a pleasing addition to a growing fleet of Experimental locos! Now looking to getting an order in soon for the Fell - I gather once decorated samples are in, the order book will close soon after.

Checked mine over and all but just a few have cracks, though a number of them are very minor but could propagate over time I would imagine. The worst is a spine-length crack on both in B724C (£19.53). Looking at them very closely, it is difficult to tell if there is a plastic outer casing over a metal structure but either way they do appear to be some kind of laminated structure.

Re-read my post... just to clarify the actual Tom Moore model boxes were enclosed in brown cardboard boxes but those boxes weren't wrapped in the loose FedEx wrappers like other BCC deliveries usually are, so the outer box would be subject to rain. So when I said 'yes', I was referring to the wrappers on previous items as being FedEx bags. Can proof read posts many times but it's only when you submit them you realise ambiguities!!!

That would be great! LT45029 is the same type and number as the EWS one Bachmann released previously (P/N: 39-778)... so it's just a question of whether another run of a 4-TC's is likely. I guess I now have to say "...or all three!"?!

Yes - one of the loose bags, usually providing some rain protection against the cardboard box inside. I called BCC about the 20's following their announcement this week and while on the phone, asked if the Tom Moore sets were in and was told that the OO sound ones had only arrived in the previous few days and were in the distribution section. By chance, I think it was the same afternoon that the packages arrived, so I must have been very quick off the mark getting the order in when announced. Having missed the Hornby 66, I was pleased Bachmann did a set especially as it has the two aircraft. However, I now have four aircraft having the N gauge model too ... will have to setup a mock dogfight as a salute to the late real Sir Tom Moore.

Hi big jim, Not yet unboxed mine but mine came a couple of days ago... one N gauge and one OO, with sound. The label on the box suggests 'FedEx' and 'Next Day'. Unlike many previous BCC deliveries, they didn't have an outer plastic wrapper, just basic cardboard box 14x14.5x5 inches, each. I ordered (+paid for) mine when announced. Hope that helps? Ixion.

...or both

Paid in full for the first run when ordered but still waiting here too...

I hate being that person too!

If you mean modern day GWR mainline... search YouTube for 'Class 92 Didcot'! 6X44 in 2011 included a DB red 92. The video says there may have been up to 3 visits by a 92 at Didcot in 20 years! So, you can 'justify' a purchase

I'm still waiting too, all paid up in advance. I can promise future orders but only after this order is fulfilled.

Yes, I am too...

Hi adb968008, That's a helpful video. I don't know if my model makes a noise or not but the video you put together was first class in my view... assessed what the problem was, determined a solution, tried a 'proof of concept' and then put it in place, all clearly presented. Regarding the concern about igniting paper - I guess it's possible, though probably not likely. However, if kapton tape is folded back over itself to build up a tab of the appropriate thickness that should also work and probably be less risk (if there is a concern). However, I would also imagine that by pushing the paper in, the barrel of the motor contacts the chassis better on the opposite side, allowing better heat transfer to the chassis, keeping the motor slightly cooler. Either way, glad it got sorted for you and thanks for sharing it! Ixion.

Sorry Retro-man... I did say with 2 people... MY MISTAKE ALSO... 100 a day, 2 people = 5 working days, not weeks... OOOPS! But worth remembering that that 5 minutes per package is rather quick.

Hi Tim, I am too. I ordered mine quite late though but I imagine there's quite a few to send out still. Only as an exercise to reassure myself (or anyone else!), I thought it through - and it's only guesses on numbers, I should point out... If one model is prepared and wrapped every 5 minutes, for 8 hours 20 minutes a day, that's 100 a day... with 2 people, that's 5 weeks (working days) to send out 1000 models... assuming no toilet breaks and nothing 'Fell' that needs attention elsewhere If KR Models can give a rough idea on percent done, that would be great - 25, 50, 75? Really looking forward to mine but appreciate it may be a bit longer yet. Cheers, Ixion.

I probably wouldn't (or shouldn't?) go for 313's (& 314's) as... I like the GWML... where electric trains mean 80x's or 387's (maybe even an 87!)... I like ROG diesel locos... 37's, 47's, 57's,... I like unusual trains... like railtours, track machines, scrap trains...oh wait... Darn! Now I've got to have one... or two... but that only makes one (scrap) train to Newport... So, even a GWML layout can have a few!

Absolutely fantastic news! I enjoyed watching the WOR announcement about these fascinating wagons. I'm sure there'll be an order coming from me No doubt they'll sell well, especially the Dragon ones. Cheers, Ixion.