A Ballerina's Face Lift

[Fezwig]

Having been tempted into G scale the Newqida Harz 6001 look-a-like and then moving on to the hard stuff, I soon got fed up with the blue front headlamps, so off to an electronics shop, buy 2 white led's and swap them over, no problem!!
Well I took the lamps off and looked at the front end...Hummm, it's a bit fat me thinks, don't like the buffer beam...Hummm, So off with the front pony truck, out with mister hacksaw!!



After a bit of chopping and muttering


Better, but need to sort out that coupling hole...Hummmm


A bit of wood glued in and the coupling end shortened, so the loop swings enough for R1's if needed (have sort of set R2/3 as minimum) and built up a new laminated plasticard buffer beam,

Just now add the air brake pipes, the vacuum ones removed and maybe a steam head pipe and job done.....errr well, not so, those lamps I was on about... well....,
see the led's I got don't work, so can anyone help??

As the saying goes, When your up to your arse in crocodiles, it's hard to remember the original objective was to drain the swamp!!

Pete
oh yes, there's the cab roof vent is as built and the front 2 side cab windows are a bit big, oh and that rear buffer beam..........

 

[pugwash]

You've killed it...

 

[Zerogee]

I have often wondered why they called it "Der Ballerina" when it's so short and tubby.... maybe it's a German joke that doesn't translate well.....
By "the Hard Stuff" I assume you mean that Harzbulle 2-10-2?

Jon.

 

[PhilP]

You DID get the new LED's the right way round? - They are polarity dependent.
(Apologies if this is teaching to 'suck eggs')..

Failing that, I have one here I can have a look at..
Mine is quite old in the ?brown and orange? 'Train' box, so might not be the same??
From memory, it has a nasty old-school circuit board in it!

 

[Fezwig]

You DID get the new LED's the right way round? - They are polarity dependent.
(Apologies if this is teaching to 'suck eggs')..

Failing that, I have one here I can have a look at..
Mine is quite old in the ?brown and orange? 'Train' box, so might not be the same??
From memory, it has a nasty old-school circuit board in it!

Did try them both ways (the old blue ones still work), have tried them directly to the battery, one worked,but a bit dim (led not me....I think?) the other didn't work at all, had tried them before I started and they where OK
Pete

 

[ntpntpntp]

The LEDs will need series resistors to limit the current. Value depends what input voltage they're fed with?

[edit]
Sorry - forgot we're talking about replacing the existing blue LEDs so they should already have suitable resistors in the wiring or on the board.

DON'T connect direct to the battery, that'll probably blow them!!

As mentioned, check the polarity.
[/edit]

 

[Fezwig]

The LEDs will need series resistors to limit the current. Value depends what input voltage they're fed with?

[edit]
Sorry - forgot we're talking about replacing the existing blue LEDs so they should already have suitable resistors in the wiring or on the board.

DON'T connect direct to the battery, that'll probably blow them!!

As mentioned, check the polarity.
[/edit]

Arrr! Did try them to the battery, with the resistors, that may have killed them.

 

[PhilP]

Arrr! Did try them to the battery, with the resistors, that may have killed them.

If it was WITH THE RESISTORS, you *should* be OK..
However, nothing is certain, except 'death and taxes'!

 

[Rhinochugger]

If you do it properly, you can sometimes get a nice resounding 'pop' when you blow them - at least it's comforting to know that you've actually blown them and it's not some other problem

 

[ntpntpntp]

OK, so in your PM you said you couldn't get either of them to work from the battery with resistors? Do you know what value of resistor Maplin provided? Wondering if maybe the resistance is too high for running them off a 7.2V battery?

As a rough guess, given
Battery voltage 7.2V
LED forward voltage = 3.5V (typical for a white LED)
current = 15mA (safe but enough to light it)

then the resistor would be 270 ohms.
http://led.linear1.org/1led.wiz

220 ohms would make them a bit brighter at 20mA. Should be plenty bright enough!

 

[Fezwig]

OK, so in your PM you said you couldn't get either of them to work from the battery with resistors? Do you know what value of resistor Maplin provided? Wondering if maybe the resistance is too high for running them off a 7.2V battery?

As a rough guess, given
Battery voltage 7.2V
LED forward voltage = 3.5V (typical for a white LED)
current = 15mA (safe but enough to light it)

then the resistor would be 270 ohms.
http://led.linear1.org/1led.wiz

220 ohms would make them a bit brighter at 20mA. Should be plenty bright enough!

Thanks, got 2 new LEDS on the way into work this afternoon, I think they are 5volt, will have a think about it for the next 2hrs on the train from Euston
by the way Rhino, they didn't go pop sadly, can't beat an impressive failure!!

 

[Paul M]

Thanks, got 2 new LEDS on the way into work this afternoon, I think they are 5volt, will have a think about it for the next 2hrs on the train from Euston
by the way Rhino, they didn't go pop sadly, can't beat an impressive failure!!

Agree with you about impressive failures, a good loud bang makes it all worthwhile
LEDs are current dependant, not voltage dependant, I'm sure others will explain far better than I can

 

[ntpntpntp]

... got 2 new LEDS.. I think they are 5volt

LEDs aren't voltage governed devices, it's the current that's important. Hence the need for a series resistor calculated to limit the current for a given supply voltage. When you calculate the resistor you need to know the "forward voltage drop" across the LED (which can be different for different colours etc.), and subtract that from the supply voltage to find out the voltage that must be dropped over the resistor. Hence you can calculate the required resistance using Ohm's Law using that voltage and the desired current.
Online calculators like the one I linked to in my previous post make it easy!

However, saying that you can get LEDs with built-in resistors to make them suitable for direct connection to - say- 12V.

 

[Fezwig]

OK, so in your PM you said you couldn't get either of them to work from the battery with resistors? Do you know what value of resistor Maplin provided? Wondering if maybe the resistance is too high for running them off a 7.2V battery?

As a rough guess, given
Battery voltage 7.2V
LED forward voltage = 3.5V (typical for a white LED)
current = 15mA (safe but enough to light it)

then the resistor would be 270 ohms.
http://led.linear1.org/1led.wiz

220 ohms would make them a bit brighter at 20mA. Should be plenty bright enough!

Thanks, got 2 new LEDS on the way into work this afternoon, I think they are 5volt, will have a think about it for the next 2hrs on the train from

Agree with you about impressive failures, a good loud bang makes it all worthwhile
LEDs are current dependant, not voltage dependant, I'm sure others will explain far better than I can

Best bang and flash, was a class 37 main generator letting go on Shap, the control cubical got fried to, should have gone to a pre wedding meeting, so got second explosion when I got home!

 

[Rhinochugger]

LEDs aren't voltage governed devices, it's the current that's important. Hence the need for a series resistor calculated to limit the current for a given supply voltage. When you calculate the resistor you need to know the "forward voltage drop" across the LED (which can be different for different colours etc.), and subtract that from the supply voltage to find out the voltage that must be dropped over the resistor. Hence you can calculate the required resistance using Ohm's Law using that voltage and the desired current.
Online calculators like the one I linked to in my previous post make it easy!

However, saying that you can get LEDs with built-in resistors to make them suitable for direct connection to - say- 12V.

Ah, I never understood what forward voltage drop was

 

[Paul M]

Ah, I never understood what forward voltage drop was

Something to do with too many beers perhaps?

 

[dunnyrail]

Interesting work you are doing here. Without doubt some of your work will be required for my one when I get round to backdating it to 1981 condition. Of note is the way you have swept the new Buffer Beam in with a curve that is less prominent just like the real thing.

Below are 4 in a row with the Newquid one at the rear, my LGB one at the front. Note the overexagerated sweep of the Buffer Beam, a job to be sorted just as you have.

This is how she appeared in 1981, sorry pic a bit dark my iPad would not allow me to do any magic on the scanned image.

Here she is in 2011, the buffet beam is not so prominently seen now due to some piping connectors.

Finally to help you another view of the rear taken in 2011.

Looking forward to more updates on your revamp.
JonD

 

[Fezwig]

Thanks to you all for your help and advice, after lunch, out came the soldering iron and a quick check showed 3 volts to the lamp, the LEDs where rated 3.5 volts, so that was ok, I put the 2 resistors in line and soldered the whole lot up


They do seem a bit dimmer, so may have got away with out the resistors, still they are more of a marker light than a head light.

Four Jon!!!
I'll get the hacksaw across to you!! I think one should be green (21) at least, that how she was when I saw her first in 1994, I may go that way when I've sorted the cab and rear out, any way, pleased with how it's gone so far.

Pete

 

[dunnyrail]

Pete,
ta for offer of Hacksaw!
JonD

 

[Fezwig]

Part 2.
Dealt with the rear end last week, again re building the buffer beam

the old lower bit removed and rear pony truck coupling removed.

rebuilding the same as the front

Then I set to making the leading cab window smaller by removing the original glazing and cutting it down to sit in the frame, leaving a space for a new plasticard smaller window frame to sit on top, but flush with the cab side

trouble is the open window now looks a bit large! another job!

Still needs a bit of filling around the new window, but happy with the buffer beam now, there is a bit of swing in the rear coupling and I done a few test through some R1 reverse curves pulling and propelling with no issues, now to the cab vent and filling in the speaker grill on the bunker (the sound never worked anyway, ain't I the lucky one!!!)