Is there a test tool...

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raistlin295
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Is there a test tool...

Postby raistlin295 » Sun Feb 26, 2012 4:09 pm

... that you can run along trackwork to detect precisely where the DCC supply is (or, more importantly), isn't please?

Or perhaps a simple device might be made up using an LED? I'm unsure as to what voltage / polarity etc one might be looking for when checking to see if DCC power was available at any given point on the track.
Paul

Finsbury Road My Layout

jcm@gwr
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Re: Is there a test tool...

Postby jcm@gwr » Sun Feb 26, 2012 4:26 pm

I would recommend a multi-meter, cheap enough from places like Maplins, etc.
I got mine from Screw-fix ages ago, it's so useful for all kinds of testing and
accurate as well.
Jeff

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raistlin295
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Re: Is there a test tool...

Postby raistlin295 » Sun Feb 26, 2012 4:50 pm

jcm@gwr wrote:I would recommend a multi-meter, cheap enough from places like Maplins, etc.
I got mine from Screw-fix ages ago, it's so useful for all kinds of testing and
accurate as well.
Jeff



I have one Jeff, but as I said, no idea what the voltage / polarity is
Paul

Finsbury Road My Layout

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Flashbang
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Re: Is there a test tool...

Postby Flashbang » Sun Feb 26, 2012 4:58 pm

Hi
In the most simplest form a visual indicator can be made from one LED and one resistor and a Peco or similar track sleeper.
Take one Standard LED with a working voltage of 2.2 volts and one 1K0 OHM 1/4watt minimum wattage resistor. Solder resistor to the longer lead of the LED.
Cut off the rail fixing chairs carefully form the sleeper top on each side of the sleeper and feed the free LED wire through one hole in the sleeper. Lay the resistor along the sleeper and then feed the free wire end of the resistor down through the other sleepers hole. Bend both wires on the underside of the sleeper outwards and then cut off any access wire beyond the sleepers end.

To use, power up the DCC and apply the sleeper tester with the LED uppermost across the rails so as both wires on its underside are able to touch the rail tops. The LED will illuminate regardless of which way around if the power is available.

As suggested already, the best way is to obtain a cheap <£10ish digital multimeter and use it on its ac range of 20 volts or higher .
Note: The reading obtain isnt accurate on DCC but is a good guide and should be constantly the same all around the layout.
These multimeter's aren't restricted to the railway use, but can also be used around the home and car etc as an electrical testing tool.
http://www.maplin.co.uk/domestic-multimeter-37279
Or
http://www.maplin.co.uk/ut30b-digital-compact-multimeter-46498

DCC swaps polarity so you use a meter on its ac range. Voltage is roughly between 12.5 to 16 volts ac
Last edited by Flashbang on Sun Feb 26, 2012 5:06 pm, edited 4 times in total.
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poliss
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Re: Is there a test tool...

Postby poliss » Sun Feb 26, 2012 5:01 pm

There's the RRampmeter. A snip at a mere £50.94.

lennie
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Re: Is there a test tool...

Postby lennie » Sun Feb 26, 2012 6:16 pm

Yes there is. PROSES VT-001 TRACK VOLTAGE TESTER. For HO/OO two Rail £9.99 From.
www.ontracks.co.uk Or have a look at Page 20 Model Rail. March Issue. Regards.

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raistlin295
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Re: Is there a test tool...

Postby raistlin295 » Sun Feb 26, 2012 6:36 pm

Thanks all :)
Paul

Finsbury Road My Layout

BromsMods
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Re: Is there a test tool...

Postby BromsMods » Sun Feb 26, 2012 11:26 pm

poliss wrote:There's the RRampmeter. A snip at a mere £50.94.


Or cheaper if you shop around!

Martin71
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Re: Is there a test tool...

Postby Martin71 » Mon Feb 27, 2012 9:18 am

Hi

In the next 6 months or so a new digital multimeter (Cat3) will be released which can measure DCC and has being designed with the modeller in mind. eg on board led tester plus the usual stuff, Amps AC DC Voltage Ohms etc. It will include a basic manual to get you started plus detailed one for the more technical minded.

Thats all the info I have.

Martin

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Re: Is there a test tool...

Postby Bigmet » Mon Feb 27, 2012 11:42 am

jcm@gwr wrote:I would recommend a multi-meter...

Along with a soldering iron, and the ability to use it, this should be regarded as an esential piece of kit for electrically powered railway modelling.

Set the multimeter for AC volts, and a range with 25V in mid range. With no locos running (and sound off if you use it) measure the DCC system output on the terminals of the system, and write down the number. (It isn't completely accurate as a voltage measurement, but that doesn't matter for this purpose as it is going to be used purely for internal comparison.) Then set the trains running, whatever number you normally have going at once and especially any sound equipped locos if you use them, and repeat the measurement on the DCC system terminals, and write down the number.

If there is a difference greater than 10% between these two numbers, then you are getting close to the limit of the system power supply. If that's the case you need to think about a greater capacity system.

Assuming the difference between these numbers is small, then go testing round the track with the trains running, and compare to the 'running system' number. If you find locations on the track where the measurement is more than a couple of percent down on what was measured on the system terminals you need to improve the layout wiring: heavier bus wires, more connections from bus to rail.

Ark Royal
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Re: Is there a test tool...

Postby Ark Royal » Mon Feb 27, 2012 6:21 pm

the other option is to use an old wagon you don't particularly want, and use a bulb and resistor across the wheels (or use a hornby 0-4-0 with the motor taken out and the bulb where the motor was). the resistor might not be necessary, so if the bulb is really dim, take it out (but make sure your bulb can take 20+ volts). then tow this wagon round, and if the bulb flickers/ gets dimmer, then there is a dodgy connection

Hope this helps

Chris
If you have found the above helpful, please read my layout thread and offer a comment
viewtopic.php?f=22&t=36868
Chris
Aka Ark Royal Aka HMS Ark Royal V (on other forums)

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raistlin295
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Re: Is there a test tool...

Postby raistlin295 » Mon Feb 27, 2012 7:48 pm

Thanks for the idea Chris, but I am wanting to be pin-point accurate as to where the power disappears and re-appears, the problems being centred around a complex group of pointwork (NOT Finsbury Road, I hasten to add ;) ).

Running exclusively Co-Co, Bo-Bo, A1A-A1A or 1C0-C01 locomotives doesn't give much of a clue either ;)

I've ordered one of those PROSE testers pro tem.
Paul

Finsbury Road My Layout

Ark Royal
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Re: Is there a test tool...

Postby Ark Royal » Mon Feb 27, 2012 8:57 pm

You're welcome for the idea

I know from painful experience how horrible fault finding is, as I spent 2 hours today fault finding a circuit with over 150 jumpers, 2 PCBs and too many components!!!

And the worst bit :

I still have no idea what the problem is :twisted: :twisted: :x :(

GRRRRRRRRRRRRRRR

Chris
If you have found the above helpful, please read my layout thread and offer a comment
viewtopic.php?f=22&t=36868
Chris
Aka Ark Royal Aka HMS Ark Royal V (on other forums)

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Essex2Visuvesi
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Re: Is there a test tool...

Postby Essex2Visuvesi » Tue Feb 28, 2012 8:02 am

Ark Royal wrote:You're welcome for the idea

I know from painful experience how horrible fault finding is, as I spent 2 hours today fault finding a circuit with over 150 jumpers
And the worst bit :

I still have no idea what the problem is :twisted: :twisted: :x :(

GRRRRRRRRRRRRRRR

Chris


Simple with 150 jumpers on its overheating :D
Si quam primum vos operor non successio , impono

The only stupid question is the one I didn't ask

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Ark Royal
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Re: Is there a test tool...

Postby Ark Royal » Tue Feb 28, 2012 4:42 pm

Thanks for that E2V

you cheered up my day and im crying with laughter.

It was actually overheating, mainly cos my retard of a friend soldered 2 wires the wrong way round

GRRRRRRRRRRRRRRRRR (again)

Chris
If you have found the above helpful, please read my layout thread and offer a comment
viewtopic.php?f=22&t=36868
Chris
Aka Ark Royal Aka HMS Ark Royal V (on other forums)


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