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2mm Coal Tank test build

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Fully agree with Jerry. Very helpful to see Ian's post with the cap pack against the decoder - which I guess is a CT 76 - and the size comparison that can be made showing just how small some of these bits are. Although I have seen Nigel's packs in the flesh and working it still amazes me the results that are produced.

 

Hats off to you all!

 

Izzy

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Starting with the components:

  • resistor (labelled 1000 for 1kohm)

 

 

That's 100 ohm. It's 1, 0, 0 and 0 multiplier following the usual resistor code, but with 4 digits. 1K would be 1001, or 102 in 3-digit code.

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Thanks. Of course it is 100 ohm. I should stop posting too late at night.

 

The ceramic capacitors are, supposedly 100uF each, so 800uF for the eight. I did try three 100uF (120v) tantalums, which I thought would end up the same overall size, but as I said, it ended up just slightly too large to fit. There was very little difference in electrical performance, both the ceramics and tantalums produced a small fraction of a second extra running after cutting the power, but every little helps.

 

I do have some 220uF 16V tantalums which are a bit smaller than the 100uF ones, so I might try three of them and see if that improves things.

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Here are some pics of my Coal Tank, now almost finished (I think). I'll see if I can make myself a stay-alive after seeing Nick's amazing demo.

 

post-12813-0-75925000-1501001763_thumb.jpg

 

post-12813-0-61061500-1501001803_thumb.jpg

 

After these shots I changed something on my camera and the rest of the shots had a slight blue hue to them. Maybe I pressed the 'blue hue on' button by mistake.post-12813-0-02296500-1501001893_thumb.jpg

 

post-12813-0-44531000-1501001984_thumb.jpg

 

post-12813-0-74944700-1501002082_thumb.jpg

 

The coach is the Highland Railway Director's Saloon, which in my model world, has been preserved and given a pseudo LNWR livery re-paint.

 

Nig H

 

 

 

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Of the small CT decoders, I think the DCX76 series are the easiest to access the solder pads.  The DCX75 is the hardest, so use a different decoder !  

 

 

Nigel,

 

You mentioned that the DCX76 was easier for access to the solder pads. On the attached photos which are the solder pads that need accessing? I am hoping that you specify those on the reverse side rather than the top as the latter two are considerably smaller but not, I think, impossible!

 

post-9616-0-22358300-1501518839_thumb.jpg

 

post-9616-0-48804900-1501518863_thumb.jpg

 

David

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Look up the decoder details in either a CT manual, or on the 1001-digital.de website.

 

Click photo on right for labelled enlargement of the rear of decoder. 

https://www.1001-digital.de/pages/digitaltechnik/lokdecoder/ct-elektronik-tran/tran-dcx76.php

 

 

- Nigel

 

Thanks, Nigel. I had looked at the 1001-digital site before posting but as my German is non-existent I was finding navigation a bit difficult!

 

I assume that the indication 'masse' (trans:ground) is the negative. Does this mean that either of the pads can be used?

 

David

 

Edit: just noticed that the circuit board also has GND printed next to them.

 

Further edit: looking at my latest version of the DCX76 it has GND only next to the square middle pad on the right. You may just be able to see it on my photograph but it is clear on the actual board.

Edited by DavidLong

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Wonderful job, Nigel - love the finish.

 

David

 

Nigel does a beautiful rendition of 'Northern grime' it must be said

 

Chris

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Thanks, Nigel. I had looked at the 1001-digital site before posting but as my German is non-existent I was finding navigation a bit difficult!

 

I assume that the indication 'masse' (trans:ground) is the negative. Does this mean that either of the pads can be used?

 

David

 

Edit: just noticed that the circuit board also has GND printed next to them.

 

Further edit: looking at my latest version of the DCX76 it has GND only next to the square middle pad on the right. You may just be able to see it on my photograph but it is clear on the actual board.

 

German translation - both Google and Microsoft (Bing) offer online translation tools which do a decent job of German websites.

 

Masse = Ground,  in theory both pads could be used if they really are ground.  A multi-meter on the decoder should indicate if they are connected (reverse the meter leads when checking, just incase there is a diode in the way somewhere, should connect in both orientations if it is a connection).   Data on 1001-digital.de website is usually accurate, so I expect they are connected.  (don't have a decoder here to check).

 

 

- Nigel

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Hi guys,

I just found this discussion about the images on my website. They are only valid for the first revision of the DCX76 (red board). Tran has changed the layout slightly for the version with the green board, resulting in swapped pins for front and rear lights (he fixed this by a firmware update in newer decoders). The back side has also been changed, so there might be only one connector for ground left. I haven't checked this yet, but you better stick to the one that is still marked as GND. It's the one closer to the NEM651 connectors on the image with the red board.

 

I'll update my site soon to give accurate information about the grren DCX76, too.

 

Hope I've been of help :)

 

Best regards

Carsten

 

Btw., I have been thinking about making an english version of my site. But I don't think I can handle this by myself...

Edited by 1001-digital
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Really impressive!

 

I had been less convinced about going DCC for 2mm steam locos, both as I was fearful about greater risk of shorts on brass bodies compared to RTR, and also feeling that without lights etc, there was less of an advantage. But seeing these results with the stay-alive, I'm pretty much convinced! Not least as soldering on the DCX76 doesn't look as bad as I'd feared ...

 

Justin

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Hi guys,

sorry, it took a while to add the information, but the Version 2 of the DCX76 is now online: https://www.1001-digital.de/pages/digitaltechnik/lokdecoder/ct-elektronik-tran/tran-dcx76.php

 

I have also checked the pads for GND, the one that is marked on the red circuit board is still connected to the GND pad on the green one, so you may use both of them if you wish. Note that Tran forgot to uncover the pads for AUX1 and AUX2 on version 2, so you have to use the 2 pads on the upper side of the decoder. Unfortunately they are harder to connect, there are some chips nearby.

 

Best regards

Carsten

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I haven't been doing much model making since the AGM (October is always a bit of a "dead" month modelling-wise with the start of the academic year) however my thoughts have recently turned to finishing off my Coal Tank after a 2-year hiatus.

 

It has been travelling round the country with me this year, assisting with various talks and demonstrations on DCC Stay Alive. Being unpainted and sans-details has had its advantages given the amount of handling it has endured, but now I just want to get the poor thing finished. (Tempted to add "and painted", but better not get carried away!)

 

Earlier in the year I managed to re-set the quartering to left-hand lead without having to un-solder the crank-pin cap washers, simply by repeatedly tweaking each axle in turn. Amazingly, I didn't bend the coupling rods and it still runs very nicely. The irony is that I may yet have to remove the rods and make them thinner if I want them to pass behind the front footsteps! (The rods are still the stainless steel version, laminated with superglue while the nickel silver variants have now disappeared altogether from the Shop 2 list...)

 

This week I made a (re)start on the body detailing.

First job was to fill in the holes in the boiler I'd drilled for fitting the handrail pillars and make some new ones. I used Milliput to fill the holes. Originally I'd drilled these holes before the boiler was in place on the model. I'd used the rotary table set vertically in my Proxxon milling machine, and taken angular measurements from published drawings... but by a combination of incompetence and wishful thinking managed to get them not only in the wrong place, but out of line as well. (how is that even possible?)

I don't know if the side tanks are too tall, or the boiler is too low, or something else is wrong... but there is definitely something strange about this kit as I had earlier needed to reduce the height of the cab sides to make everything fit together. Still, it looks the right shape for a Coal Tank! 

The second attempt at positioning the holes involved scribing a line along the in-place boiler tube, spaced from the bottom of the footplate valance using my digital calipers. I also drilled other holes for various fittings to the smokebox, and the thing is starting to do a good impression of a piece of Swiss cheese. For an example of Victorian elegance, there are an awful lot of "bits" to put on.

 

I seem to be having difficulty drilling small holes in exactly the right places at the moment. You may be able to see in some of the photos below where my holes aren't exactly on the scribed lines. I usually make a dimple with the point of my scriber to start the hole, but I've had the drill wander off on a few occasions. Maybe it is because I am drilling into a curved surface. I'm hoping the end result won't look too rustic.

 

There are some tank-top details on the etch which needed to be added before any of the pipes or handrails. I started with some plates with 6 rivets (which needed pressing out from behind) to hold the tanks to the boiler at the front. These needed shortening at the non-riveted end, which I did by eye. Next to them are some round plates with 3 rivets which again needed pressing out. Amazingly I managed to solder these on without un-soldering the tank tops or anything else.

 

Next layer up on the fireman's side is the vacuum ejector pipe which lies along the tank top. This is made from Nickel Silver wire (0.5mm diameter - it's a 3" pipe on the prototype). There was a little collar on the etch to go on the smokebox end, but the hole in this had over-etched making it hard to locate accurately. I decided to make a replacement by filing an etched crankpin cap washer down to about 4 thou thick.

On the other side of the boiler I've added a representation of the top end of the reversing reach rod.

 

The cast sand-boxes from N Brass were quite a bit too tall as they came, so needed filing down. (In fact, all the Coal Tank castings I got from this source are over-sized) This meant removing the detail cast onto the top of the sandbox. Fortunately, the etch has sandbox filler lids, which I have added. I've also drilled holes to locate the operating rods.

 

All the above can be seen in this view looking down on the tank tops:

IMG_9865.JPG.3896b302b8c104e13e625c607100cfc5.JPG

IMG_9873.JPG.00e9ff87dc4ae598dc43b91afdb4f576.JPG

The lubricators on the sides of the smokebox are required a bit of thought.

At the moment I've got as far as the little trays that catch the drips. (These were added to the prototype to prevent oil drips getting into the sand boxes, and they drain into the smokebox)

These are formed at either end of a piece of 0.8mm brass wire which passes through the smokebox. A short length of wire at each end was bent up to 90° and then filed back flush with the horizontal piece to make the rounded ends. It took a couple of goes to get the overall length right. The lubricators themselves will plug into the holes above the trays. The ball of a turned brass handrail knob is about the right diameter for one of these, and may form the basis of one...

 

The fireman's side tray can bee seen in this picture:

IMG_9871.JPG.8abaa9bebce3da8f46c101b07f7a5937.JPG


Somehow I managed to get the hole for the tray on the driver's side too high, and had to drift it downwards.

The photo below shows clearly the mess I've made (which will require filling) along with a comparison of the sandboxes before-and-after reducing them in height:

 

33605487_sandboxesbeforeafter.JPG.400026849eb15954890d11cb037ecb65.JPG

 

The two little holes higher up on the smokebox are where the blower valve will fit. This attached to the end of (and operated by) the handle.

The other hole in the side of the smokebox (near the front) is where the operating linkage for the sanders passes through the smokebox in a tube. These are operated by the other handrail. Making the little cranks and supports for these is going to be fun! The ones I made for my L&Y Radial tank (photo below) are positively chunky in comparison (and hidden under the boiler).

987890072_radialtanksanderlinkage.JPG.ab406bab3ed11cd06e07912700fb1632.JPG

 

There is still quite a long list of little details to make and add... plus the as-yet unanswered question of how to fix the cab roof in place.

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A tiny bit more progress to report.

In the photo below you can see the driver's side handrail, which has the blower valve fitted at the front end. The handrail is plain steel 0.008" guitar string. The knobs are Association etched ones. I slid a length of micro brass tube (Albion Alloys) over the end before bending to form the body of the valve.

IMG_9885.JPG.2a5785f1a878af4bb9bfdb01a135e3d4.JPG

 

Also in the photo above, on the other side of the smokebox I've made a start on one of the lubricators. This is a turned brass handrail knob (I keep finding uses for them other than as handrail knobs!). Once soldered in place it has been filed town to approaching half its height to form the bottom of the lubricator body.

 

IMG_9878.JPG.3c1f00edc8576fd6fc567b17d748bc48.JPG

Below is the matching one on the left hand side.

 

IMG_9888.JPG.ce600d03a4f629581a8afe5dffcefef8.JPG

 

I turned two cylinders  (0.8mm diameter to match the handrail knobs) from brass rod, to represent the upper part of the oil pots. The idea is that these will peg into the knobs.

 

IMG_9876.JPG.33d73b5010020f78d0e94a3a13d07964.JPG

 

Once fitted, I think these lubricators have turned out as well as I hoped they might.

 

IMG_9897.JPG.c3ad549f9205fddfcfce81f70f0c781f.JPG

 

I remembered to put filler in the gap above the drain cup on the left side before fitting the lubricator body. Milliput says it is heat resistant up to 130°C, but it has survived the much higher temperature of my soldering iron. Some of the Milliput I'd used to fill the wrongly placed holes in the boiler side did turn green when I soldered next to them!

 

IMG_9893.JPG.274690c33082688e60c577c8a2d453d2.JPG

 

I've had to think quite carefully about the order in which the details are being added round the smokebox in order to maintain access for the soldering iron.

The operating linkages for the sandboxes are under way...

 

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I have added the fireman's side handrail and sander operating linkages.

It is probably easy to tell that the crank from the front of the handrail to the upright pivoting shaft is an etched handrail knob.

The next crank down is another handrail knob, but this time with the shank cut off completely, and the half-etched tab (one in three knobs on the fret have these) used as the crank arm.

The cross shaft is a single piece of 0.25mm nickel silver wire passing through the smokebox like the prototype. (On the real thing it moved inside a tube - mine doesn't, which made for an interesting job finding the hole from the inside when threading the wire through...)

I squashed the end of the cross-shaft wire flat with pliers to solder to the handrail knob / crank. I couldn't do that with the steel wire of the handrail itself.

 

aIMG_9905.jpg.d685b6ebec89185ac7543ac052243363.jpg

 

On the other side, the vertical shaft is shorter.

I used nickel silver for these vertical bits - 0.3mm, which is on the thick side, but I wanted them to be a bit more robust - there's nothing really holding them in place at the top end other than the cross shaft, which is free to slide sideways. I chickened out of using 0.2mm steel (as used for the handrails) partly because the etched knobs are a slightly loose fit and would therefore be more difficult to avoid getting them wonky, and also I find nickel silver generally easier to work with. I'm on the edge of what I find possible to hold and solder with these details, without having one bit dropping off when the next bit is soldered on.

The things I chickened out of adding were the brackets/pivots that hold the top end of the uprights to the sides of the smokebox. I did have a go at making some from flattened out 0.2mm copper wire wrapped round the shaft. They are quite well hidden in most photos, and with the other bits being over-scale thickness, next to the cranks it was all starting to look a bit too "full", so I decided to leave them off.

There are more rings of micro brass tube (the next size up from Albion Alloys) at the bottom of the uprights.

 

aIMG_9907.jpg.c556be6007c50e8b6b556df25fa690cf.jpg

 

Now that the smokebox has numerous bits of wire poking into and though it, I needed to revisit the chimney I made and shorten the mounting spigot.

That and the other turnings for dome and safety valves are just balanced in place here, and so is the roof. I decided to pose the body on the chassis just to get an up-to-date impression of how the overall picture is coming along. It is certainly starting to look like a coal tank, and well worth the effort.

 

aIMG_9915.jpg.af3b4c9b18cc4987b8a8fe716a59ef84.jpg

 

Here's a last view (for now) and a rather cruel one(!) looking along the top of the loco.

At last I've managed to get a shot where the lighting shows up the crease under the smokebox door, where the cylinder fronts are angled at 1:8..

I will have to make sure I line up the turned boiler fittings more carefully when I finally fix them in place...

 

aIMG_9922.jpg.e5b7450966254a64daee738f1220917f.jpg

 

I'll be moving on the the"face" next, I think. Alas, nothing is supplied on the etches by way of a hinge plate or door wheel.

 

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Looking good, Nick - I must dig out my previous attempt and have another go - got the chassis running after a fashion, but messed up badly with the front end on the body.

 

David

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Absolutely top modelling Nick. You are an engine building genius.

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20 minutes ago, -missy- said:

Absolutely top modelling Nick. You are an engine building genius.

missy at this risk of hijacking this topic welcome back hope to see your excellent work again posted 

 

Nick 

Edited by nick_bastable
clarification
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On 13/11/2019 at 21:21, nick_bastable said:

missy at this risk of hijacking this topic welcome back hope to see your excellent work again posted 

 

Nick 

I second that 

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While procrastinating over whether to try and slim down the N Brass tool boxes or make new ones, I thought I would have a go at adding the footsteps and test out the clearances.

I say clearances, but it turns out there aren't any included on the etches, so I have had to make my own through low cunning and subterfuge.

 

To strengthen the running plate, I had used .5mm square section brass in lieu of the 8 thou etched strips in the kit. This enabled me to drill holes in the centre of the brass valance to mount the steps.

The etched treads are soldered onto 8 thou steel guitar string. By drilling the hole in the valance 0.3mm, I was able to insert the wire (which is approx. 0.2mm) at an angle, sticking outwards. By bending the wire down to the vertical, it gave me the extra few thou I needed to enable the coupling rods to pass behind the steps. The bottom edge of the steel wire is chamfered, so if it does touch, a shourt sircuit will hopefully be the worst that can happen rather than the rods catching, jamming and mangling.

 

I don't think the bend is too noticeable:

 

steps1.jpg.76573b2e5604fbf9627a37ba7bcbd8c6.jpg

 

There is some sideways movement in the wheels. When they are pushed right over to one side, the clearance is only a couple of thou. Mind you, the clearance for the brake pull rods is similarly negligible...

 

1434475316_steps4.jpg.def69a9639db13f194ea6d6680958eeb.jpg125815367_steps5.jpg.84d53db9262c7c224f2041f6cab0323f.jpg

 

At the rear end it is a similar story.

The cab step backing plates actually fit into a slot etched into the floor. This is set back quite a way from the valance. I decided to make use of this slot as it would ensure the alignment of the steps, but I needed to crank them out to allow the radial truck to swing. The picture below is angled to accentuate the bend, but it doesn't look too obvious in real life. I could have filed off the tab and soldered the backing plate to the rear of the valance, but this way gives the sense of them being set further back. 

 

1998741794_steps8.jpg.ae2b62717663787af5a6a70af58e975f.jpg

 

It is only at the extreme edge of the bottom steps where there is a chance of contact being made. I have moved them out so that when the radial truck is at maximum deflection, there is a few thou. clearance remaining.

 

1715406422_steps6.jpg.61e02f883b090f0a16c2ae814f155b51.jpg1908924269_steps7.jpg.60a8e0ac32d0589d5f6cd06f4d47b862.jpg

 

At least half the time making the steps was spend crawling on the floor looking for wayward treads. Most of the rest of the time was spent re-soldering on the vertical handrails which my fat fingers kept dislodging as I was gripping the body.  Speaking of wayward step treads, as supplied, the sides of the treads have a half-etched line to bend up. I felt they looked a bit silly as the bent-up sides were very tall. I cut these down to about half their original height which looks a lot better. I know the back part of the upper treads under the cab should bend down under, not over the tread, but I was concerned that with the half-etched fold lines, if I folded it (or the side pieces) the wrong way I would be in danger of weakening and snapping something off. As it is, I felt it necessary to flood the inside of the step tread with solder to add a bit of strength. Everything about this loco seems so very delicate!

 

So far, on test, it still runs!

 

Here is a general view of the underside of the loco, showing how busy things have got:

 

905540741_steps3.jpg.d9f01e4cf8d72b11f381ae3604d8f48e.jpg

 

 

Edited by Nick Mitchell
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Having taken time off to build a Fowler 2-6-4T (plus a few other distractions), the Coal Tank is now back on my workbench for finishing off the seemingly endless list of details. I have reached the milestone of having attached every usable part from the etches.

 

At the rear end, I've added the tool boxes. These are home made, with the basic shape filed form brass and the hinge straps added from strips of shim. You can see in the photos that part of the underside of the tool boxes has been filed away to give clearance for the stay alive capacitors in the bunker. They might look a bit skinny - I was struggling to find good photos or drawings for these, so resorted to measuring a Bachmann 4mm model. A good coal load will partially obscure them anyway...

 

243046528_rearend.jpg.baacbd3b7cd6b2e2fd30069fc01c2ea9.jpg

 

The lamp irons were supplied on the etched fret, but I had to re-make the top one, filing it out of scrap etch. This iron stands proud of the bunker rear, with a second layer of etch across the bottom arm of the inverted T shape.

 

The bottom 3 irons were supplied as flat pieces of strip, which required bending all in the same place. I drilled small holes in the bunker rear to locate them, which was quite a delicate operation - the rear sheet didn't quite reach the bottom of the bunker when I originally assembled it, with the gap being filled with solder. Also, because the metal is only 4 thou thick, it is very easily distorted. I should really have put a reinforcing piece behind it, and marked/drilled the holes while it was still flat on the etch, but you live and learn! The irons were soldered in place from inside the bunker.

The rear vacuum brake pipe is a confection of copper wire.

 

803759176_rearend2.jpg.0a206e172750be1b7e5db50e4deee467.jpg

 

I had originally bought some tool boxes form N Brass. As with the rest of their Coal Tank castings, these were grossly over-scale - even if they were meant to be N Gauge. I had started filing them down, but in the end decided it would be quicker and easier to start from scratch.

Here is one of the castings, slightly filed, for comparison!

 

142334670_toolbox.jpg.eef095c0aa3572e71765804d3d9afd90.jpg

 

I also had to re-make the tender filler. I haven't fitted it yet, but here is my turned version compared with the casting.

 

32782195_tenderfiller.jpg.d87261e2724ccfc79301ef82223f3639.jpg

 

I'm still pondering how best to fix the roof on, but it will need detailing. Coal tank whistles are very small indeed. I've had a go at turning one on the end of a length of 0.6mm nickel silver rod. The major problem is getting the slit narrow enough. I've done this one with a piercing saw blade and made it as deep as I dared.

 

whistle.jpg.c117ecf002b954537d61d2a3886a507f.jpg

 

Some years ago (about 15) I got hold of a pair of really nice turned brass whistles from BH Enterprises. I recently acquired some more, but these were about double the size of the original pair. N Brass do a cast "Small LMS" whistle, which is similar in size to the original BHE ones. Turns out that for a Coal Tank, the whistle needs to be much smaller than any of these. By way of comparison, here is my current effort held next to one of the old BHE whistles, which is fitted to a 4F.

 

1501911284_whistlecomparison.jpg.2c27a8048dae4f86e4e49dbe8dddd23e.jpg

 

On the chassis, I've added the operating lever for the front damper, which passes diagonally across the bottom of the firebox and ash pan - just visible in the picture below. I've also fettled the front guard irons so they don't touch the brakes (and thereby short the body to the chassis), and fitted sand delivery pipes.

 

1398029243_coaltank.jpg.347e8b292a4faf6c73ec676a1ca073ff.jpg

 

I've got some details to make and add around the cab area now, including the reverser and a tangle of pipes. Because the cab is fairly open, it will be worth trying to suggest some of the interior detail. Below is the start of the firebox back-head, sawn and filed from 1mm thick brass. The curved recess in the bottom edge will clear the top of the motor, which protrudes slightly into the cab.

 

backhead.jpg.b016f9664a51c21d6dc233145946b112.jpg

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