Hornby Zero 1

[betamax]

Anyone out there who can provide more information on the old (very old) Hornby Zero 1 system?

I recently acquired motive power with the Zero 1 decoder installed, but would like to know more about it. Info on the internet is sparse, or just very generic.

[jrbernier]

  Zero 1 was a very early(late 70's) command control system.  Walthers imported/handled it for a while.  The decoders were always 'touchy' and everything was very expensive for the time.  A local modular 'logging' group used it(mid to late 80's) until getting good decoders was a problem, and eventurally converted to DCC in the 90's.  The command station and throttles sort of attached to one another and the unit kept getting longer as you added more to it.

  I doubt if anyone really wants the stuff anymore, but mabe you could sell the decoders at a train show or on-line.

Jim

[garya]

Two of my friends used it on their layouts. It was a proprietary command control system developed by Hornby in the '70s, and allowed independent train control. I believe it was limited to 16 different addresses. I'll ask for more info.

Both of them have since switched to DCC. I'm not sure what the market is for Hornby Zero 1 now.

[garya]

I found some more information in Peter J. Thorne's 34 New Electronic Projects for Model Railroads (Kalmbach Books, 1982 ISBN: 0-89024-039-6). I quote:

The Zero 1 is a computer system: the nerve center of the master control unit is a Texas Instruments TMS1000 4-bit microprocessor chip....

There are four units to Zero 1. Up to three slave units can be added to the master control unit simply by snapping each to the preceding unit. Connections are by 15-contact printed circuit board edge connectors. At turn-on there can be four fully independent locomotives under control; the master control unit is automatically assigned to loco 1, and each slave to 2, 3, 4 respectively.

The master control unit can be used to assign any of the 16 digitally controlled locomotive receivers to any of the slave units or even to the master control unit itself....

The small size and simplicity [of the receiver] are made possible, in part, because the track voltage is a + and - square wave. The receiver motor control is, therefore, a triac, which in effect is a bidirectional SCR, though two SCRs are used in some versions of the receiver....Track power is square wave, one form of AC, generated by a pair of power transistors in the master control unit. The triac or SCR pairs in the receiver conduct on the positive part for forward, or are synchronized by pulses to the negative part for reverse. Although track voltage swings from +22 V to -22 V, the average is 11 VDC, since the square wave is only on half the time, and onlf half is on for either direction....

The Zero 1's control system is based upon a 32-bit code generated by the TMS1000 microprocessor, which is transmitted every third cycle of the square wave track voltage. For the 8.33-millisecond interval during which the coded information is transmitted, it replaces the track voltage. Because the track power is turned off when the coded information is transmitted, the system is highly resistant to electronic interference. The code contains the identifying pulse for each of 16 locos and up to 99 auxiliaries.

Lighting could be a problem, as the bulb would see the full 22 v of the square wave ac, and would be on all the time. I also gather that you had to push a lot of buttons.

An address for a US repair station is listed as P.O. Box 160, Goshen, KY 40026. 25 years later, I doubt it's still good. My friends took a road trip to Cedar Rapids, IA, a few years ago to buy parts; I'm not sure if the dealer they bought from still carries Zero 1. Hornby invested quite a bit of money developing Zero 1--the books states over a million dollars--but it may have been too soon.

[betamax]

Thanks, that was more along the lines of what I was looking for, as I wanted to flesh out the info on teh dccwiki about this system.

I've already torn the decoder out and replaced it with a Digitrax DH123. Now the locomotive needs some lubrication, and possibly, a motor transplant. Otherwise, it works OK.

[garya]

I'll see if either of my friends has an owner's manual left. Thorn's book does have illustrations of the square wave, the units, and the receiver, so if you can hunt one done it may be worth it--I found mine at a show for $.50.

[locoworks]

a couple of people have posted that people moved from zero 1 to dcc, i thought zero 1 was dcc? if only an early version??. either airfix or hammat and morgan did a similar system, but i don't know if they were compatible. a friend of mine picked up a zero1 master controller with a couple of chipped loco's last year for around $50.  the big problem with the system was that the frequency of the wave was not very high and the motors of the time basic/primitive, so if you ran a loco slowly for a length of time things would burn out due to the heat build up.

[ukrailroader]

Hi to everyone from me in the UK,

The problem with Zero 1 was that if the decoder lost it's address it had to go back to Hornby for reset. I don't think the decoders were programmable either. I thought about trying the system when it came out but didn't like the prospect (if things went wrong) of 20V AC going through my 12V DC motor.

If anyone out there has a Zero 1 system still working, the UK firm ZTC make a decoder for Zero 1.

[Mark R.]

The original Zero-1 decoders had a series of small pads along the outside edge of the decoder. The address of the decoder was made using electrically conductive paint to join a combination of pads to create the individual address.

Also, the Zero-1 could be compared to the likes of an old rheostat DC controller in that it would not control the more modern high efficient can motors. Speed step one would cause a can motor to take off at almost full speed.

Mark.

[Anonymous]

Lots of technical stuff on here.

 

http://www.princeton.edu/~mae412/volume.html

 

You need to look at all the links, but there is the best covereage online.

Report what you think.