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Farish Jinty, 4F, Ivatt 2MT - 2FS & DCC/stay-alive. Also NGS Hunslet Industrial


Izzy
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Hello Peter,

 

Glad to be of assistance..   No, very sorry, the PB is some very fine stuff I have had for well, decades really. Haven't got a clue where I got it either....and I am down to the last 12" now, a very small coil.

 

I'm afraid I don't have a modern digital caliper to measure it or the DG stuff accurately, but on my old analogue one it's around 0.15mm/38SWG as against the 0.3mm/30SWG of the DG PB. So just a bit thicker than the wire used in N couplings, but much stiffer. Here's a couple of comparision shots to show the difference.

 

1037978379_RMwebivatt2mt34.jpg.6f63bc2a188d8adab898dda978df8180.jpg

 

755376527_RMwebIvatt2mt35.jpg.129695ca9b7b747c40756194e6bc5bbe.jpg

 

I would guess the thicker stuff could be used while making allowance for it so tension drag wasn't too great. Use longer lengths etc. I'm afraid I have tried using the coupling spring stuff but found it's just too fine/not strong enough for the job as with producing simpson springs, which is what I keep it specially for. Or rather don't use it for anything else.  It would be very handy to locate some more.

 

best regards,

 

Bob

 

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Ooh- I have a coil of the 36 swg PB wire. It's marked 0.193mm-0.0076" will that work? I think I bought it for pickups.

 

There's enough for several lifetimes so I can pop a hank in the post if you like, if you don't have enough to justify an order from Eileen's 

Edited by nightmail
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6 hours ago, nightmail said:

Ooh- I have a coil of the 36 swg PB wire. It's marked 0.193mm-0.0076" will that work? I think I bought it for pickups.

 

There's enough for several lifetimes so I can pop a hank in the post if you like, if you don't have enough to justify an order from Eileen's 

 

Thanks Peter, that's very kind of you, but I need a few other bits so I'll do something after Xmas. I must admit 12m coils will last a fair while.....plenty to experiment with at least.....

 

Bob

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  • Izzy changed the title to Farish Jinty & 4F - 2FS & DCC - with stay-alive. Now also Ivatt 2MT & a re-build for better haulage
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Another excellent post Izzy. I found my converted Farish 4Fs to be very sweet runners but a bit whimpy in the haulage stakes. I've fitted one with a weighted tender which has made a considerable difference so I will do the others at some point.

 

Jerry

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Thanks Jerry. Glad it’s of interest. With the lower tenders, and especially the Johnson 3,250’s this kind of adaption wouldn’t be possible so I had been wondering what to do with mine and might give that a try seeing as how I stuffed the CT decoder in the top of the firebox. 
 

Bob

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With Priory Road now as I want it more time can be spent on stock. So I have now been able to finish off the 2mt. The numbers are Modelmaster, the emblems Railtec, while the lining, well..... that's 4mm HMRS pressfix, eeek...  As I wasn't sure how to do it I thought I'd just take a look at the 4mm PC/HMRS sheets of LNWR/BR stuff I had to get an idea where I could go. There are a couple of suppliers of 2mm BR mixed traffic lining, but to be honest I was wary of either. Being able to get it in the first place, the quality in the second.

 

Looking at the sheets and comparing them, the width and quaity in comparison to shots of the Farish 2mt in this livery - which of course would have been the easy option if I had one  - gave me this silly idea that I could use them cut up a bit and it might not look too bad. I thought it worth a try. Not sure what others think but I feel it's acceptable, especially after the weathering.

 

1382118856_RMwebIvatt2mtdone01.jpg.67e0c0d89ca6e316834ec7b2679c4482.jpg

 

1657163915_RMwebIvatt2mtdone02.jpg.c7db52468e1f1b32ae4636142a22bbe3.jpg

 

1379104716_RMwebIvatt2mtdone03.jpg.48f7fedb324891110b67fd71de1a50c1.jpg

 

433056158_RMwebIvatt2mtdone04.jpg.42a3920e0e16f4bc8cfca810758885d6.jpg

 

1981902752_RMwebIvatt2mtdone05.jpg.8a57b54dcbf45935a50c6eeb773d8901.jpg

 

I should point out that the numbers are in the correct position. Not being central on the cabside, a bit higher up, looks wrong but is exactly how the actual loco was from a photo that was used of it at Colchester in 1960. Funnily enough an earlier photo of it at Colchester in 1951 when new shows the numbers as being larger, deeper, this with the original Lion-on-wheel emblem. Seems later numbers may have been smaller/shallower.

 

Now I must really try and get on with the N7/3....

Edited by Izzy
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Izzy,

If you hadn’t said that the lining was 4mm scale I for one would never have known. Certainly after weathering had “knocked it back”.

On my GWR stuff, I’ve used Fox transfers exclusively (except the awkward curves around the cab side openings which I’ve brush painted), and am more than happy with the results.

Ian

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1 hour ago, Ian Smith said:

Izzy,

If you hadn’t said that the lining was 4mm scale I for one would never have known. Certainly after weathering had “knocked it back”.

On my GWR stuff, I’ve used Fox transfers exclusively (except the awkward curves around the cab side openings which I’ve brush painted), and am more than happy with the results.

Ian


Thanks Ian. I always think a little weathering in the form of a light patina helps with black locos to show a bit of detail through increased contrast but it ended up a bit heavier than I intended although it does seem better in the flesh than in the shots. I have been wary of the Fox offering for BR mixed in 2mm since I read it was very overscale, and there now seems different sheets offered at different standards so very confusing, but perhaps I just need to take a chance and give them a go. 
 

Bob

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I have now managed to re-load all the images to this thread, apart from of course any posted by others. While the original information about the Farish 3FT Jinty conversion has now really been overtaken by the availability of conversion parts from the 2mm association some aspects might still be helpful in regard to other locos so I will leave all the posts regarding it as they stand.

 

Bob

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Well that's wierd.

 

Today I got out the Ivatt 2MT along with my N7/3 to give them a test on my latest layout which is just about finished. The N7/3 sauntered up and down quite okay, but when I changed the fiddle yard track to use the 2MT there was no initial responce followed by a crack/short circuit sound and then light grey smoke just poured out of the loco/tender footplate joint....arg.!!! The acrid smell filled the room and hung about for a long while, even with the windows open.

 

Oh dear I thought, a Zimo MX617 decoder up the creek. But more importantly, why? Separating the loco and tender and then popping off the tender top revealed this state of affairs.

 

712338506_RMwebIvatt2mtRB23.jpg.c0047cad06380fb8d4411aa1a2dc21d0.jpg

 

774235014_RMwebIvatt2mtRB25.jpg.2a2754e546a1c6b1cab8bcee1dcfe68b.jpg

 

One of the three 220uf 16v Tantalum capacitors in the home brew stay-alive pack had just gone 'pop'. Stripping the pack out and taking it down to the individual parts gave this sorry mess.

 

1737232322_RMwebIvatt2mtRB26.jpg.277838f18a1e967b2871f555796da39c.jpg

 

Now I have absolutaly no idea why this happened, except that perhaps the capacitor was faulty somehow. I have had one of these D case type do this before, but that was when a SA pack was being made up and tested before fitting into a loco. At the time I just assumed - dangerous I know - that the odd faulty one was to be expected.

 

But it's been in the loco and under use for quite a while and there is no inherent short issue anywhere. The rest of the components seem okay when tested with a DM. The best news was that the Zimo 617 was fine. Without the SA the loco ran just fine.

 

1543544494_RMwebIvatt2mtRB27.jpg.6b6a0db6120dd2b10f83874ba0707471.jpg

 

So, since it has 12 wheel pick-up, 6 loco, 6 tender, and the SA was fitted just as a kind of belt and braces job I have now chosen to leave it without. This is partly because the capacitor had started to melt the plastic around it even being wrapped in masking tape, nothing serious or showing thankfully, but I'd rather not take the chance of it happening again and ruining the tender top.

 

Every day's a learning experience isn't it?

 

Bob

 

 

 

 

 

 

 

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Hi Bob,

 

It might be worth checking your track voltage. Some older DCC systems used to run higher which caused over voltage on the capacitors, I can't remember the exact figures but remember quite a few N scale modellers in the states having capacitors blow up in this way.

 

There was also a habit to save space by wiring the capacitors directly to ESU decoders without the additional components. It works but they need disconnecting when programming. 

 

My only suggestion, until someone more knowledgeable appears, is to check the voltage at the capacitors on another locomotive and ensure it's not above 16V under power.

 

HTH

 

Bryn

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Hi Bryn,

 

The SA circuit I use is the one posted here - in the coal tank thread I think - by Nick Mitchell which has a 16v zener diode across the poles to bypass any excess current in addition to the usual diode/resistor bits, so overcurrent shouldn't really happen. My GM Prodigy Advance Squared also gives a track output of about 15v so everything seems okay on that front, but many thanks for the suggestion.  It is concerning when something happens you can't account for, and especially when I have around a dozen locos, maybe more I'm not sure, which have been given these home brew packs.  The N7/3 I was also using has one so it is a strange situation. Both decoders are Zimo, MX617's.  But the fact the system CB didn't go off until after the bang would seem to indicate over current. Puzzling.

 

Bob

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Bob,

 

How strange! I've been on a hunt for information on this and have come across an article which might be of use

 

https://www.onelectrontech.com/tantalum-capacitor-failure-modes-and-causes-esr/

 

It's a heavy read but gives various failure modes;

 

1. Failure caused by high voltage of low impedance circuit

2. The peak output current is too large

3. Tantalum capacitor ESR is too high or AC ripple is too high

4. The leakage current of the tantalum capacitor is too large, resulting in insufficient withstand voltage

5. Failure caused by production and assembly

 

I tend to agree with your solution, remove them unless the loco suffers without! 

 

Bryn

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I think this sort of failure is in the "not unexpected" category.   The components are rated to 16v.  But those are "on the line" limits of the component, and often one is recommended to not go above 70% or similar of the rated values.    But, in 2mm scale that gets impractical for size reasons.   I've only had capacitors go "pop" in test situations with half-built circuits which were probably shorted or otherwise abused.  

 

My own DCC system is under 14v at the track (accurate measurement).  One could use a Zener rated to 14 or 15v to limit the voltage in the capacitors to a slightly lower value, the excess volt from the DCC system would be drained via the "charging" resistor, and then through the Zener - some basic sums on likely current through the Zener would be needed, but my gut-feel is that it will come out as "inside spec".   

 

 

Component options are getting smaller; in 4mm scale I now use off-the-shelf charge management circuits rather than resistor/diode DIY.   I expect inclusion of such circuits on smaller decoders will happen in time.  

 

 

One can have commercial stuff just fail - I've just returned a £100+ sound decoder which stopped playing sounds (completely) within a few days.  I'm confident that the supplier will sort it. 

 

 

 

- Nigel

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1 hour ago, Nigelcliffe said:

I think this sort of failure is in the "not unexpected" category.   The components are rated to 16v.  But those are "on the line" limits of the component, and often one is recommended to not go above 70% or similar of the rated values.    But, in 2mm scale that gets impractical for size reasons.   I've only had capacitors go "pop" in test situations with half-built circuits which were probably shorted or otherwise abused.  

 

My own DCC system is under 14v at the track (accurate measurement).  One could use a Zener rated to 14 or 15v to limit the voltage in the capacitors to a slightly lower value, the excess volt from the DCC system would be drained via the "charging" resistor, and then through the Zener - some basic sums on likely current through the Zener would be needed, but my gut-feel is that it will come out as "inside spec".   

 

 

Component options are getting smaller; in 4mm scale I now use off-the-shelf charge management circuits rather than resistor/diode DIY.   I expect inclusion of such circuits on smaller decoders will happen in time.  

 

 

One can have commercial stuff just fail - I've just returned a £100+ sound decoder which stopped playing sounds (completely) within a few days.  I'm confident that the supplier will sort it. 

 

 

 

- Nigel

 

Thanks Nigel, your comments help to put it into perspective in that it is just something that has to be accepted/taken into account when using small components like these. I am relieved to know that most of the locos which have these packs are metal bodied so the risk of heat damage from an occurance such as this is mitigated to a great extent. Hopefully it will stay as an isolated experience for there is no doubt they are a wonderful asset to small locos. It was of course the sight of your 02 sautering around my layout which convinced me I just had to tackle making and fitting them to some of mine.

 

Bob

 

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Okay, I've just had another 16v/220uF tantalum go pop, the loco just sitting on the layout as before. This was in my N7/3. The circumstances seem identical to previously. A Zimo MX617, the furthest tantalum from the 16v zener diode etc.  And happened when other locos were in use on the layout. I am just trying to figure if there is a common factor here and one to avoid.

 

Looking around I have got some 220uF 25v tantalums coming via ebay. The case size seems the same. These should solve the problem I think. Worth a try anyway.

 

Bob

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I'm just wondering Bob, what is your track voltage?

I still use my Bachmann EZ Command most of the time, but I replaced the power supply with a 10v AC version in order to lower the track voltage. This was to better accommodate small decoders, long before I got into stay-alives, but it may have had a beneficial effect there as well.

If 25v tantalums are now available in that small a case size, that's the way I'll be going regardless.

Nick.

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Hello Nick,

 

Thanks for that thought. My Prodigy system laptop type sms brick is 15v@3.5amp, and although it not supposed to be a good indication my basic MM consistently reads 14.9v track output. So not as high as I believe some are, but perhaps knocking on the door of the tantalum limits. Why only some are suffering now when others have been around for the last 5 years using the same system is where I'm a bit puzzled and so trying to find a common factor. With more than one I don't believe in coincidences.

 

Nigel made the very good suggestion to use 14v/15v zeners but I haven't got around to trying that yet. Sadly I think the 25v tantalums are E case rather than D. Didn't notice that in the specs when ordered. Same height/width of course, 7.4mm x 4.3mm, just deeper at 4.1mm against 2.8mm. Ah well, will be worth a try. 440uF that doesn't go pop might be better than 660uF/880uF that does. Luckily the N7/3 was metal so no heat damage nor any to the decoder or other bits. It's the fag of having to dismantle and re-build that's annoying...

 

Bob

 

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Just a bit of an update on the 25V E case Tantalums. These arrived today and I thought a few comparisons might be worthwhile.

 

The 16v tantalums are D case, so they are 7.3mm x 4.3mm x 2.8mm.

The 25v tantalums are E case, so they are 7.3mm x 4.3mm x 4.1mm.

 

The size difference is thus only in depth.

 

1058781502_RMwebTSA01.jpg.8561fefd3a1efda8a4a343c8df4db407.jpg

 

1054924108_RMwebTSA02.jpg.377988fdb6e04ca59c228bcea8f488c1.jpg

 

Now this means that two 25's on their side need the same space as three 16's. So only 440uF as against 660uF. However Three 25's (660uF) only need the same space as four 16's (880uF) plus the mini-MELF 16v Zener, which is 1.5mm dia x 3.5mm long. And of course as they are 25v the Zener is not needed. I know SMD Zeners are available but I'm comparing with what components I've used to date.

 

1829620361_RMwebTSA03.jpg.ee96c7740fa7693d12a56a9a5080128d.jpg

 

I'm working here on the principle that I only want a small amount of help for a loco to overcome small specs of dirt etc. not run on for ages. Under those conditions slightly less uF to offset any tendency for the 16v's to go bang is worthwhile if this prevents serious damage to decoder or loco. It nearly melted the Ivatt's tender body for example. And if space isn't a major issue it seems a no brainer now in light of my experiences. I'm rather hoping it won't happen again but I now have an alternative if it does.

 

Bob

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  • Izzy changed the title to Farish Jinty, 4F, Ivatt 2MT - 2FS & DCC/stay-alive. Also NGS Hunslet Industrial
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NGS Hunslet industrial conversion to 2FS

 

Having acquired a NGS Hunslet and converted it to 2FS I thought I’d detail the basics for anyone tempted to do the same. It was an unexpected purchase but one that has proved worthwhile. A very nice loco for extremely reasonable cost at today's prices.

 

The basics are that it shares many general design features with the other Farish locos featured in this thread, a coreless motor, split chassis current collection with pickup through the axle bearings, but also has a dedicated DCC decoder with stay-alive fitted and is able to run on both DC and DCC to choice.

 

Here's the loco split down into it's main parts. You'll have to accept I only took this shot part way through the conversion.

 

RMwebNGSHunslet06.jpg.f90a519dc8f7cbf8eab718f76f1148cc.jpg

 

The axle bearings are the same size as those used in the Farish locos, so replacing the wheels with 2mm SA 2FS wheels/bearings/muffs produced for them is possible. The only drawback here is that due to the chassis design there is minimal clearance on the rear axle for the gear train, and thinning the muff is required.

 

RMwebNGSHunslet12.jpg.488d88ad7f28369fb12258b7826ab9f0.jpg

 

RMwebNGSHunslet13.jpg.7d928efe54d82574204aeb7e31ae8f3e.jpg

 

RMwebNGSHunslet14.jpg.755d6b513ebf0a5be5ae013ffddee4f0.jpg

 

Coupling rods would need making up somehow if not reusing the originals, which it has to be said are chunky depth wise but very thin. I might try a ‘proper’ 2FS conversion this way at some stage in the future.

 

RMwebNGSHunslet15.jpg.85413614498eaff08d42d1808a7ea0ba.jpg

 

However to keep things simple for now I have chosen instead to re-machine the wheels, thin the flanges to 0.3mm so they pass through 2FS flangeways. Because of the particular design of the wheels, different to the Farish which are mazak castings but similar to those used with the Sonic J50, it has been found that reducing them in overall width is not really feasible. As a result I used a small round nosed tool to just thin the flanges inwards towards the hub.

 

RMwebNGSHunslet16.jpg.ff3683301bca85a3bceb77314e15d9e3.jpg

 

RMwebNGSHunslet17.jpg.813726ce6ca9eb00cac58197c7cc66f0.jpg

 

RMwebNGSHunslet18.jpg.dd085b0fd330934d53e9c0a0ca04e13c.jpg

 

RMwebNGSHunslet19.jpg.776632caac0ff050316f742c0746b595.jpg

 

A result of using the wheels at a wider b-t-b has been that the axle bearings need widening/moving outwards so the wheel stubs don’t fall out of them in any sideways movement. This has been achieved as I originally undertook with the Jinty by producing 0.2mm brass washers which were soldered onto the outer faces of the bearings, and then the bearings fitted into the chassis slots reversed, so the inside faces then become the outside.

 

Re-machining the wheels also meant there was no cost to this 2FS conversion. Besides this I also made some changes to the loco body livery, and replaced the N couplings with DG’s.

 

Cosmetically I decided to finish the loco as one owned by Blue Circle Cement. This was prompted by the blue finish of the body as bought. As the body is plastic and could be separated from the cast metal footplate, and the cab is a separate painted clear moulding, I took them apart and sprayed the footplate black all over. The nice handrails are easily pushed out of true with handling, so care must be taken when holding the loco. Mine came loose and careless attempts to secure them with runny cryno left blobs on the cab. So I removed them completely before spraying the footplate, stripped them of paint – they are N/S etchings – and painted and re-fitted them later. I then cleaned up the cab before putting all the bits back together.

 

RMwebNGSHunslet07.jpg.9398f21c4998ee1f550d851361611f11.jpg

 

RMwebNGSHunslet09.jpg.62dd851e7030a4b77602bf0757f7767f.jpg

 

RMwebNGSHunslet10.jpg.2d37331a236f9121a37d8bae2570f675.jpg

 

The Blue Circle logos on the cab side were printed onto white inkjet transfer paper sealed with ‘Ghost’ matt spray varnish. The yellow warning stripes on the buffer beams were more transfer paper, but given a coat of Revell enamel paint before cutting into strips and applying. Trying to inkjet print yellow just didn’t work. It was far too pale, just no colour depth, and almost unseen. A wash of dirty black was applied over the body to highlight the panel details etc. and further weathering with Rowney pastels to represent a coat of cement dust which it would undoubtedly have will be done when I get around to it.

 

RMwebNGSHunslet05.jpg.81a2c9fbf695609aa2efded2c3ef3bb1.jpg

 

 

Bob

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Thanks Bob, very useful information as I've also acquired an NGS Hunslet for British Oak. I was planning to use 2mm driving wheels but seeing your photos, I shall follow your option of thinning down the flanges.

I'm wondering if it's worth making some new axles to suit the increased width over the outside faces of the wheels set to 2mm back-to-back standards.

Mark

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46 minutes ago, 2mmMark said:

Thanks Bob, very useful information as I've also acquired an NGS Hunslet for British Oak. I was planning to use 2mm driving wheels but seeing your photos, I shall follow your option of thinning down the flanges.

 

The key with thinned flanges is extending (or creating new) bearing blocks so the wheels are adequately supported.

    

A different axle length is a very small matter in comparison to the bearings.  

 

 

- Nigel

 

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