4mm Polsarrett: BR(S) N Cornwall Clay, The Final Countdown

[Pencarrow]

Ah, but, the Engineer in me says “wouldn’t it be good if…?” and given Chris’ profession, I suspect…

Guilty

 

[Pencarrow]

Not directly, but I understand that Geoff was responsible for much of the control systems on Lime St.

Having had the pleasure of operating that magnificent model, and assuming I haven't crossed my wires, I think you’d be in safe hands. It just worked. Perfectly.

it may be a trick of the light, but are your posts placed on the corners of a rhombus? They’ll need to be if they’ll work!

atb
Simon

They will be, yes Simon.

Just plonked in place at the moment to get a feel for how the look.

 

[simond]

They will be, yes Simon.

Just plonked in place at the moment to get a feel for how the look.

I’m guessing no wheel in the box?

in which case, I guess the latch of the gate nearer the box should be at the end nearest to the box, if that makes sense?

 

[Pencarrow]

And the answer to the question of "have I drilled through the Megapoints controller servo board?" is...


Yes.


And the answer to "does it still work?" is...


No.

 

[Pencarrow]

So the drill bit caught the board where the red arrow is. As far as I can tell it's gone through a single track and no components.

Is the repairable by soldering a wire between two points on the same track?



What do folk think?

 

[simond]

Yes, you can fix this.

Ultra fine point soldering iron, cored electrical solder. No other flux!

use fine abrasive paper to remove the varnish over the tracks either side of your “crater”. Not sure if it’s one or two tracks to repair.

get some very fine (eg 0.2mm) copper wire - you can extract single strands from hookup wire - if it’s varnished, you’ll have to use the abrasive to remove same.

a couple of strands might be twisted together, probably not required given the apparent size of the tracks.
cut the wire about 6” longer than you need so you have a handle.

tin the tracks where you’ve cleaned off the varnish; Hot iron, tiny drop of solder, in-out quick.

tin the wire, plenty long enough. Bend it so it sits nicely in place.

hold the other end of the wire.

solder in place; Hot iron, tiny drop of solder, in-out quick.

snip off the handle.

repeat as required.

test

assuming it’s ok, drop of enamel or nail varnish to protect.


alternative.

very thin varnish-insulated wire, solder to the pad at each end. Make sure you get the connections right. Once tested & ok, a drop of something to stick the wire to the PCB, to prevent a snag pulling it off.

hth
Simon

 

[Peter Cross]

Going back to how gates like this where operated. The ones. We used to pass to get into the yard at Early. Were hand operated, by oneself, but, were lock at anytime when a train was due.

 

[Pencarrow]

Yes, you can fix this.

Ultra fine point soldering iron, cored electrical solder. No other flux!

use fine abrasive paper to remove the varnish over the tracks either side of your “crater”. Not sure if it’s one or two tracks to repair.

get some very fine (eg 0.2mm) copper wire - you can extract single strands from hookup wire - if it’s varnished, you’ll have to use the abrasive to remove same.

a couple of strands might be twisted together, probably not required given the apparent size of the tracks.
cut the wire about 6” longer than you need so you have a handle.

tin the tracks where you’ve cleaned off the varnish; Hot iron, tiny drop of solder, in-out quick.

tin the wire, plenty long enough. Bend it so it sits nicely in place.

hold the other end of the wire.

solder in place; Hot iron, tiny drop of solder, in-out quick.

snip off the handle.

repeat as required.

test

assuming it’s ok, drop of enamel or nail varnish to protect.


alternative.

very thin varnish-insulated wire, solder to the pad at each end. Make sure you get the connections right. Once tested & ok, a drop of something to stick the wire to the PCB, to prevent a snag pulling it off.

hth
Simon

Thanks Simon. I must admit I'm really rather cross with myself. I think your first option sounds well beyond what I could manage. I am considering having a go at adding a wire across the two hole terminal thingies. Even that worries me because I'm concerned about cooking an adjacent component. What temperature would you recommend setting the iron at? I'll then have to look at what the smallest bit I have for the iron.

 

[Pencarrow]

The track that's severed goes between the holes just above the two yellow dots. I've tested the continuity of the other two tracks nearby and they are fine. It's definitely the two yellow dots points as there's continuity between them and the drilled hole.

 

[michael080]

[... ]use fine abrasive paper to remove the varnish over the tracks either side of your “crater”. Not sure if it’s one or two tracks to repair.
get some very fine (eg 0.2mm) copper wire - you can extract single strands from hookup wire - if it’s varnished, you’ll have to use the abrasive to remove same.
a couple of strands might be twisted together, probably not required given the apparent size of the tracks.
cut the wire about 6” longer than you need so you have a handle.
tin the tracks where you’ve cleaned off the varnish; Hot iron, tiny drop of solder, in-out quick.
tin the wire, plenty long enough. Bend it so it sits nicely in place.
hold the other end of the wire.[...]

Alternatively, you could investigate where the track ends and connect the end points directly. Risky, if you get the wrong connection, but easier to solder the wire to the pads than to the track.

Michael

 

[Pencarrow]

Alternatively, you could investigate where the track ends and connect the end points directly. Risky, if you get the wrong connection, but easier to solder the wire to the pads than to the track.

Michael

I've given that a go. Let's see what happens next...

 

[simond]

Sorry, been busy…

looks like a good fix, if the continuity is ok. From the first picture, I thought there might have been two damaged tracks.

does it work?

if so, glue it down to prevent snags and open a beer to celebrate.

 

[Pencarrow]

Sorry, been busy…

looks like a good fix, if the continuity is ok. From the first picture, I thought there might have been two damaged tracks.

does it work?

The rest of the tracks have continuity and are fine.

I've plugged it all in and it works, apart from the 12th output which is currently linked to the leftmost turnout. I'll have to move the turnout to another output.

 

[simond]

Well, that’s a positive outcome, if you can manage with one output not working. Is there a second damaged track?

possibly between 7 & 9 o’clock on your crater?

I think you’d be able to do the same sort of repair on that track too.

 

[Pencarrow]

Well, that’s a positive outcome, if you can manage with one output not working. Is there a second damaged track?

possibly between 7 & 9 o’clock on your crater?

No, that track goes around a bend not past the crater. The tracks are tested and all work. No idea why output 12 is kaput.

 

[simond]

Ah, ok.

your earlier question:

I phoned a friend, who phoned a friend…

“Right, here's an answer from a signal engineer..

More often than not push the rods when lever pulled, but space contraints may reverse cranks in box so the opposite.

Half way up the run push converted to pull by W shaped compensator from two cranks back to back to provide weather and temperature compensation so they usually work without adjustment.”

Hth

 

[Mark F]

I didn't get quite as far as I'd hoped with the wagons:

Aiming for a balance of durability and accuracy, I'm pleased with how they are turning out. Having worked out how to do various bits and batch built a few components I'm hopeful the rest will come together a bit quicker.

 

[Pencarrow]

I didn't get quite as far as I'd hoped with the wagons:
View attachment 159855
Aiming for a balance of durability and accuracy, I'm pleased with how they are turning out. Having worked out how to do various bits and batch built a few components I'm hopeful the rest will come together a bit quicker.

That looks really good Mark, great job.

 

[Pencarrow]

Ah, ok.

your earlier question:

I phoned a friend, who phoned a friend…

“Right, here's an answer from a signal engineer..

More often than not push the rods when lever pulled, but space contraints may reverse cranks in box so the opposite.

Half way up the run push converted to pull by W shaped compensator from two cranks back to back to provide weather and temperature compensation so they usually work without adjustment.”

Hth

That's good to know, thanks Simon. I was working on the basis that it was a push from the box but, having done so, kept finding examples where it was a pull. I decided in the end that there wasn't a fixed rule and it probably depended on the orientation of the last crank in the box.

It did seem though that push was more prevalent, which your friend of a friend confirmed. Good stuff. I'm aware of the need to balance the push with the pull to counter expansion.

 

[Pencarrow]

Any joy chum as the suspense is killing us.

I just phoned the printers as I was going to collect the backscene at lunchtime. Guess what?

Still not printed. I've been promised Wednesday...