H&M handheld help

[sir douglas]

just bought a hammond & morgan handheld but i cant get it to work, i bought it for a fiver to try out to replace my current AMR which has some dead spots in it, i got it only knowing its a handheld and didnt see the H&M on it, anyway i thought i could just directly wire it in place of the AMR through the Hornby transformer plug i use to power it, which didnt work. I know ive got the right pair of wires because it says on it which colour wires are in and which for out, i tried switching the 2 wires round and nothing. there is power going through but when i put a motor to the output wires, it just buzzes, shakes but doesnt turn and after a few seconds the overload button pops. what am i doing wrong with the input power?

 

like this but with a red overload button and mine doesnt say anything on it about voltages

[Dava]

Have you tried 16v. AC input? Yellow wires suggests that is correct. If not you may have found why it was $5!

[jcm@gwr]

Is it possible to open it up, then you (we) could see if it has a rectifier.

that would confirm whether it should be AC or DC input (if it doesn't

already say on it)

 

You might need a different transformer though!

Edited April 2, 2018 by jcm@gwr

[Titan]

These do not have a rectifier. They require a 12V DC supply. It sounds like it has been wired incorrectly to AC.

 

I have to say these are not very good, they are simply a resistance mat and a thermal cut-out. - I bought a couple out of nostalgia to go with my duettes, but I find the standard resistance on these too low for slow speed running, and unlike the duettes they have no high resistance switch or half wave (due to running on DC) so the minimum speed is quite fast. When I get around to it I will find a resistor to put in series with it, and possibly run them on AC with a single diode to give half wave.

 

I also opened the unit up and completely replaced the cables with a couple of meters of four core like this:

 

https://www.ebay.co.uk/itm/White-Flexible-Cables-All-sizes-3-4-5-Core-3183Y-3184Y-3185Y-3093YHR-All-Lengths/121984227187?hash=item1c66d39773:m:mowOnCq8_RKXV6n7nA0AMAA

 

To give a reasonable wander capability and to make a neat job of it.

[sir douglas]

the Hornby plug im using is 16V AC R964

 

002 by Sam, on Flickr

 

005 by Sam, on Flickr

 

004 by Sam, on Flickr

 

003 by Sam, on Flickr

[jcm@gwr]

I agree with Titan (I was thinking that, but wanted to be sure),

and now the photos confirm it!

You need a proper rectified transformer.

[sir douglas]

its going a bit out of my comfort zone now, i'd rather try a different controller than try something im not confident with and not know anything about and then make something that might not put be together properly and not safe to use

[jcm@gwr]

It's not that difficult, you just need any old H&M* unit (which can be

picked up cheap at swap meets, toy fairs, model shops or even at

your local MRC), almost all of them have uncontrolled 12v DC and

16v AC outputs (first would suit your handheld, second would suit

point control.

*some Triang, Hornby and Trix units are the same.

 

P.S. if the cable is in good condition (although easily replaced)

those units will outlast that silly little plug-in transformer!

Edited April 2, 2018 by jcm@gwr

[kevinlms]

its going a bit out of my comfort zone now, i'd rather try a different controller than try something im not confident with and not know anything about and then make something that might not put be together properly and not safe to use

The easiest solution is to use a plug pack, just a different one to what you currently have.

 

You need an output of around 15 Volts DC and rated at about 1 1/2 Amps. Your nearest electronic supply shop would have such an item in stock. Connect the output of this plug pack to the yellow wires and it should be fine.

 

Edit to add. Here's the relevant page from my H&M catalogue.

Edited April 2, 2018 by kevinlms

[John ks]

You could buy a 12V DC plug pack Edit See Kevinlms's previous post for more information regarding the transformer

 

Or if you would like to dabble into electronics then a very basic circuit is to build your own rectifier from 4 Diodes (1N4001, 1N4004 or similar )

 

The diagram shows the symbol & a pic of a diode, Bottom left corner

 

I have shown the circuit as parts rather then symbols, this should make it easy to follow.

 

 

John

Edited April 2, 2018 by John ks

[DCB]

You can connect any old 12 volt DC supply to it, car battery, 12 volt DC output from a H&M controller, Scalextric transformer, 12 volt DC from a computer PSU.  Speed control will be rubbish because its a variable resistor but safe because it has s first class overload cut out with manual reset.

[SHMD]

No one should use a car battery, in the model railway room, unless it has been correctly installed and protected with calculated wire sizes and the fuse/circuit breaker sized for the load/wires used.

The only time I would do this is when the railway room is not connected to the mains - and yes, the wiring and fuses MUST BE correctly installed/insulated AND NOT some lash-up with spare bits that were to hand at the time.

 

Lead-acid Batteries have an extremely low internal impedance. This means that any short will only be limited by the batteries own internal resistance and the wiring.

I= v/r = 12/0.1 = 120 Amps! Easily enough to start a car OR a fire!

 

Most people have no concept of the internal impedance of power supplies and quite a lot of model railway wiring, shall we say, leaves a lot to be desired.

Voltages (can) kill by stropping the heart, Current (can) kill by starting fires.

 

 

Kev.

[kevinlms]

No one should use a car battery, in the model railway room, unless it has been correctly installed and protected with calculated wire sizes and the fuse/circuit breaker sized for the load/wires used.

The only time I would do this is when the railway room is not connected to the mains - and yes, the wiring and fuses MUST BE correctly installed/insulated AND NOT some lash-up with spare bits that were to hand at the time.

 

Lead-acid Batteries have an extremely low internal impedance. This means that any short will only be limited by the batteries own internal resistance and the wiring.

I= v/r = 12/0.1 = 120 Amps! Easily enough to start a car OR a fire!

 

Most people have no concept of the internal impedance of power supplies and quite a lot of model railway wiring, shall we say, leaves a lot to be desired.

Voltages (can) kill by stropping the heart, Current (can) kill by starting fires.

 

 

Kev.

Just found an old Railway of the Month (1958 March) where the author built his layout 'The Bradstock Branch', in a caravan. The power source of the layout was his Land Rover. He reported problems with the power supply being erratic, causing trains to be jerky! The cable ran around 'half his farmyard from the dash plug'. Bringing the vehicle closer to the door solved his problems!

 

I wonder what sort of cable he was using and what protection he used, if any? Sounds like a dodgy bit of thin cable.

 

Definitely not to be recommended.

[SHMD]

On the face of it a car battery sounds ideal - ie. 12Vdc, very smooth, portable and with a lot of capacity to boot.

...but against this is the very high fault currents it can deliver - think in hundreds of amps.

Now think how many times your railway has suffered a short!

 

Car jumper leads are thick for a reason.

 

 

Kev.