An old Hornby power controller restoration

[high_vacuum_house]

Good evening,
A quick restoration this afternoon as the weather was bad. This time it was a Hornby railway power controller from the mid 1980's

I purchased this to make up a model railway layout and upon power up was completely dead from the variable supply to the tracks. Tapping it and wiggling the switches would make it cause brief spurt of power.

It is a vey simple supply with 15V AC output for signals and point motors and a variable DC supply for the track to run locomotives. The power switch really just switches the bridge rectifier from half wave to full wave supply. The speed controller is little more than an in-house made wirewound resistor.

To open it 6 rivets have to be drilled out of the case, the 2 switch dollys need removing and the power knob removing as well.

The 2 switches (one for direction change and one for low and high power) are not a bought in part from a component supplier, but made in house and are easily disassembled.

Here was the cause of the almost dead supply. The switch sliding contacts were brass strips and tarnished. This came up well with some Brasso. The other major problem was with the springing of the moving contacts. The sponge strips they used had deteriorated over many years and had lost all of its springiness so that the contacts were not being pressed onto the fixed contacts. I found some silicone sleeving was an ideal replacement for the old sponge and once fitted into the contact carrier, the sliding contacts were making good contact with their fixed contacts. You can see the difference in the third picture.

After cleaning the case, switch dollys and the power knob, reassembly was straightforward and I replaced the drilled out rivets with 4BA nuts bolts and washers to complete the work. The power controller now functions faultlessly now.

[high_vacuum_house]

Finally after the case and controls being cleaned and then reassembled.

[Cathovisor]

They're mid-70s - I had one with my train set in 1976.

Never as good as the offering from Hammant and Morgan.

[Uncle Bulgaria]

I like the replacement with BA - just what I'd have done!

[The Philpott]

Reminds me I must get my Hammant & Morgan Safety Minor sorted out. (Originality set aside as a nice chunky Paignton knob with chromed pointer is now in place on the front!)

Dave

[emeritus]

I bought a Hammant & Morgan Duo for £2 at a charity shop a few years ago. It gets occasional use with its 12 V DC auxilliary output connected in series with my Farnell L30-2 when I need around 42V when periodically cycling the three SLA batteries that power my electric bike to check their capacity. Charge using the H&M and L30, discharge using three 12V 21W bulbs in series. It is also used to control the speed of my 12V Expo Mini drill.

[duncanlowe]

I had one similar, back in the 70s too. Not sure if it's in the loft, but if it is this will be a great guide to reviving it.

[SiriusHardware]

This controller comes from the original peak period of my childhood / early teens interest in model railways and at the time I was quite the Hornby fan and I wanted an all-Hornby setup including the controllers, but when I went specifically to buy a controller like the one which is the subject of this post the owner of the model shop persuaded me to buy a Hammant and Morgan 'Duette' instead.

I had something of a model rail revival about a decade ago and I spotted an H&M 'Duette' like my original one in the 'shed shop' at Grosmont on the North Yorkshire Moors Railway. It was clearly second hand, priced at £40 and I couldn't talk them down, they were adamant they would be able to get the asking price for it. So those H&M units are still well regarded after all this time, although maybe not so much sought after now because DCC (Digital Command and Control) seems to be very popular now.

[Cathovisor]

Depends. H&M controllers are sought after by Hornby-Dublo collectors instead of the "classic" A3 controller - for newer models with analogue control. Gaugemaster feedback controllers are favoured where folk don't want the expense of DCC.

[Graham G3ZVT]

Mine was an A2 like this



I got it in 1959 and it disappeared along with a load of scrap metal from the cellar of my late in-laws house about 15 years ago. I still have the engine from the set, but I won't risk posting a locomotive picture.

The transformer spent more time being abused with my electrolysis and electroplating experiments in later years.

I too drilled out the rivets, it was to replace the mains lead, but it was long enough ago for 4BA to be far more likely to be at hand than M3/M4.