John Isherwood

Someone once suggested that DCC was going to make train control soooooo simple ! Me? A steady hand on the controller, and a well-built loco running on DC, does all I need. Regards, John Isherwood.

Might I suggest that a few links might generate more sales? Regards, John Isherwood.

Thank you. Nope - straight out of the bottle. Regards, John Isherwood.

(Hattons' illustration of the model as supplied). Well, Railmatch Early DMU Green was certainly what I was looking for. After multiple applications and stripping of other manufacturers' interpretations, a couple of brush-applied coats of Railmatch enamel produced a result that, to my eyes and memory, is spot-on for the shade used on the Gloucester single cars when new. I printed and applied a set of transfers, and the reassembled model now looks like a brand-new 'bubble car'. It brings memories of the Looe Branch as sampled during my childhood holidays, when spotting at Liskeard was preferred to sitting around on Looe beach! Regards, John Isherwood.

Having taken delivery of a Heljan 1365, (in place of the Kernow / DJM version for which I cancelled my order), I was very pleased with the model. It ran smoothly and relatively quietly, though with a little 'growl'. As advised in the instructions, I set it up on rollers to run it in - but after around five minutes running it stopped dead and could not be persuaded to run again. So, I set to for a strip-down and fault-finding exercise. Firstly, it is essential to remove the under-boiler tank balancing pipe - this just pulls out of the holes in the underside of the saddle tank. Then the front NEM pocket assembly needs to be removed by unscrewing the single long screw; this reveals a screw which can be unscrewed to release the smokebox unit. The entire saddle tank moulding can now be slid forward along the internal cast weight to release it. The upper cast weight / motor clamp is released by removing the two screws now visible. With the motor now accessible, it was evident that the black wire had never been properly soldered to the motor terminal tag, and had broken free. Sliding the tiny rubber sleeve back along the wire allowed me to solder the wire securely to the motor tag, and the motor then functioned again. Though the motor fits fairly snugly into the recesses in the lower boiler casting and the upper cast weight, I suspected that the motor 'growl' might be caused by vibration between the motor casing and the castings. I therefore wrapped a single layer of thin masking tape around the motor - Sellotape would have done just as well - and then replaced the motor, ensuring that the black and red wires sat properly in their cast recesses. The upper casting was replaced and the fixing screws refitted. I track-tested the partially reassembled loco, and some adjustment of the weight fixing screws was necessary to ensure that the worm engaged the worm-wheel to the optimum extent, at which point the loco ran virtually silently, with no 'growl' whatsoever. I noted that the saddle tank moulding, when slid over the internal cast weight, had a considerable void above the weight. I therefore cut a piece of roofing lead sheet to the dimensions of the top of the weight, and chamfered the edges to 45 degrees; this allowed the lead to sit on top of the weight whilst still allowing the tank moulding to slide in place. The smokebox moulding was replaced and the fixing screw refitted, followed by screwing the front NEM pocket assembly in place, and replacing the tank balance pipe. The result is a fully functioning loco, which runs virtually silently and with significantly more mass than as supplied. Frankly, I do not think that it would be possible to produce a better model of the 1361 class, and the easy elimination of vibration between the motor and its cast surround has removed the only niggle that I had concerning running. Regards, John Isherwood.

I'm afraid the tech. speak goes over my head - I did say that I am a complete electronic novice. My stock of around 100 locos are powered by anything from the Hornby Dublo / Tri-ang X-04 era mechanisms (with five pole armatures), through Mashima and Mitsumi motors on Highlevel gearboxes or Ultrascale gearsets, Pittman motors, Romford motors, MRRC motors, and many RTR mechanisms from 30+ years ago up to the present day, including current production with coreless motors. This experiment is merely that - in order to see if voltage regulator control can at least match the performance of my aging H&M Walkabouts - which, IMHO, offer the ultimate in control sensitivity. If it fails, the component parts will find other uses in time. Regards, John Isherwood.

See my posts #14 & #25 re the Tri-ang Hornby power unit that I have been using for breadboarding; it does not have an overload cut-out - it just buzzes! See post #31 re the transformer that I have ordered; the vented enclosure that I have also ordered is rated as adequate for the va rating of the transformer. The hand-held unit will house only the voltage regulator and DPDT centre-off switch, plus the diodes; for testing purposes it will be fed from the transformer unit via a lead that plugs into an output socket on the transformer enclosure. Ultimately, it will connect to the baseboards via a 5 pin DIN plug / socket, which will provide 12v AC input to the voltage regulator and variable regulated 0 - 12v DC output to the track. The regulator has a heat sink - do you feel that the enclosed hand-held unit will require fan venting? Where and by what do you suggest the current overload should be provided - I am a total novice at this kind of thing. The transformer is rated at 20va with two separate 12v AC outputs. I did wonder whether a 50va rated transformer would be better, but it would have needed a much larger vented enclosure, which I had difficulty sourcing. If experience shows a need for a higher rated transformer, we are only talking £8.00 or so, so this shouldn't be a problem. Any other advice will be gratefully received. Regards, John Isherwood.

I have also ordered a vented PSU case, power supply jacks / sockets and grommets for the transformer, plus a hand-held enclosure, control knob, diodes, and a DPDT centre-off rocker switch for the regulator. If this project works, it should produce quite a neat and light, hand-held walkabout controller. Regards, John Isherwood.

Now that is exactly what I need - thanks very much indeed. I have ordered an https://www.rapidonline.com/vigortronix-vtx-126-020-212-chassis-transformer-230v-20va-12v-12v-88-3922 , which should be able to drive a couple of these adjustable voltage regulators, with an output variable voltage which I calculate to be :- input 12v AC - 1.2v (bridge rectifier) = 10.8v DC x 1.41 (capacitor) = 15.2v DC - 1.4v (2 No. diodes) = 13.8 v DC. So, with the diodes in place the voltage regulator should output 0 - 14v DC, whic I would have thought should be OK; (my H&M Walkabouts output 0.1 - 14.6v DC). I will report back once the transformer is to hand. Regards, John Isherwood.

Then why is this voltage regular provided with both a pot adjuster and a digital output voltage indicator? I am assuming that the device is intended to produce aa adjustable, regulated output voltage at the indicated voltage. Or am I just too much of an ignoramus to understand even that fairly basic premise. Anyway - me as a layman the device does appear to be able to function as a model train controller, and I will source a 240v / 9v transformer to see if an input from this will produce an adjustable output from the device of 1.12v - 12v (or thereabouts) DC. I really would be most grateful if someone could indicate in diagram for where and what series diodes can be added to the circuit in order to produce a 0v DC minimum output; (as suggested above). Regards, John Isherwood.

https://www.cctrans.org.uk/ Regards, John Isherwood, Cambridge Custom Transfers.

All the above is way above my head. The Tri-ang unit has, prior to the latest 'playing' with the voltage regulator, been used to provide power to my test track via two, switchable alternative supplies. Supply 1 is from the nominal 16v AC (actually 19v AC) terminals of the Tri-ang unit to a H&M Walkabout controller, the output from which gives excellent control of mechanically sophisticated loco mechanisms. Supply 2 is from the nominally 12v DC controlled terminals of the Tri-ang unit direct to track; this gives less precise control but more 'umph' for less mechanically sophisticated loco mechanisms. I have seen no evidence whatsoever that the Tri-ang unit is malfunctioning - it is actually branded Tri-ang Hornby RP14. Perhaps I should explain that I am in the process of upgrading my older locos from old-fashioned (ie. Tri-ang X04 / Hornby Dublo) mechanisms to more up-to-date Mashima / Mitsumi plus Ultrascale / High Level mechanical systems - hence the 'before and after' power / control arrangements. All of my loco stock - approximately 100 units, operate entirely satisfactorily via either Supply 1 or Supply 2 - though the former gives far more sophisticated control at lower speeds. My interest in the voltage regulator unit is purely academic. It is my (very basic) understanding that a low voltage DC motor can be controlled either via a fixed voltage and a variable current limiter (resistor), or via a variable voltage - is this correct? IF that is the case, I was interested to see how a variable voltage supply would perform vis-a-vis a traditional variable current-limited supply. I am probably way off course - but nothing ventured, nothing gained (learned). Regards, John Isherwood.

Nonetheless, the output of the Tri-ang unit, at it's lowest setting on the pot, is read as 7v DC using a multi-meter. At that input setting, the output readout on the voltage regulator's own digital read-out is 1.12v to 14.6v, depending on the setting of the regulator's pot. This is confirmed by connecting the regulator's output to track, and a loco is controlled within the full range of the regulator pot, without excessive speed at the top end of the pot range. I have NO idea of the processes going on - I can only report what I observe. Regards, John Isherwood.

Yes - with a 7v DC input the output is 1.12v - 14.6v DC, depending on the setting of the regulator's pot. Can you indicate which resistors should be adjust, and what their revised value should be, please? Remember, you're talking to a numpty as far as electonics is concerned. What diodes should be fitted where to produce a minimum output of 0v DC? Regards, John Isherwood.

I knew that, as soon as you guys got into this, I'd be out of my depth !! The Tri-ang power pack outputs 19v AC at the nominal 16v AC terminals; 17v DC at the nominal 12v DC uncontrolled terminals; and 7v - 17v (reversible) at the controlled 12v DC terminals. I can tell you that, from having tried it, powered from the 19v AC terminals, the voltage regulator's on-board digital output indicator shows 1.12v - 22.2v DC as the regulator pot is rotated. Using the 17v DC terminals on the Tri-ang unit, exactly the same output is indicated on the voltage regulator. Using the 7v - 17v DC controlled terminals on the Tri-ang unit, the voltage regulator indicates a maximum output range of 14.6v - 22.0v DC; the minimum output in all cases is 1.12v DC. So, it would appear that, using the lowest 7v DC controlled output from the Tri-ang unit, a usable output range of 1.12v - 14.6v DC can be achieved with the voltage regulator. I will test this out - but, on the face of it, a lower AC output transformer of, say 8v - 9v, may well provide the desired DC output range of 1.12 - 12v DC. As to the advice that series diodes can produce a 0v minimum output from the voltage regulator, can someone provide a VERY BASIC circuit diagram that will indicate were the diodes should be placed, and what their spec. should be, please? Regards, John Isherwood.

Thanks for all of the input - I knew there would be a simple solution; I will do just that. From my, admittedly electronically-challenged perspective, these compact units have a lot of potential as walkabout controllers. I'm thinking a project box, with the pot shaft protruding from the face, and a two-way, centre off rocker switch above it for directional control. I currently use H&M Walkabout controllers, (superb), but they're getting long in the tooth and something a little more up-to-date does appeal. Regards, John Isherwood.

Having read some mention of adjustable voltage regulator step down power supplies, I ordered and have taken delivery of one of these - https://www.aliexpress.com/item/LM317-Adjustable-Voltage-Regulator-Step-Down-Power-Supply-Module-With-LED-Meter/32618386190.html?spm=a2g0s.9042311.0.0.svpAoZ. Testing it, I found that with a nominal 16v AC supply from an old Tri-ang control unit, the minimum output voltage is 1.25v DC, and the maximum is 24v DC. The inability of the unit to output 0v does not seem to affect my locos and, combined with a cente-off, forward / reverse switch, the unit seems to have potential as a fairly sensitive control unit for 4mm. scale. However, the maximum voltage output of 24v is excessive - approximately twice what I need. Knowing nothing about electronics, my instincts suggest that an 8v AC supply should halve the maximum output to 12v - but I suspect that not to be the case. Can anyone with some electronics knowledge advise whether the lack of a 0v output will cause unforseen problems, and whether it is possible to adjust the maximum output to 12v or thereabouts, without making major amendements to the unit? Many thanks in anticipation. Regards, John Isherwood.

Please - see #438; a simple misunderstanding of your post. Regards, John Isherwood.

No - but since the post had no quote, and followed one which I took to refer to the model as a whole, my misunderstanding is perhaps not unreasonable? Regards, John Isherwood.

Errr - have you read #433? Regards, John Isherwood.

The dimension from rail to top of cab, given on the drawing as 11'-7'' (46.3mm. at 4mm. scale), measures 46.3mm. on the Heljan model. The model's wheel diameter is 14.7mm.; the prototype's is 3'-8'' (14.66 at 4mm. scale). So, I can detect no significant departures from scale with the Heljan model as far as these critical dimensions are concerned. Nonetheless - no splashers. Regards, John Isherwood.

I have just taken delivery of the Heljan version. The rail to top of footplate dimension is 16.5mm.; the rail to top of chimney dimension is 49.5mm. I have no idea what the scale dimensions should be - can anyone inform us? Certainly, the buffer height matches the rest of my stock, and the model does not give the impression of being too high. The build quality is excellent, and the level of detail more than adequate - there are some very fine (and vulnerable) separate moulding on there. A lovely runner ...... and no splashers. Regards, John Isherwood.

Larry, Is this an epiphany moment ???????? I'm so pleased that you nowadays seem to be able to resist the impulse to rip up your recently completed hard work. Congratulations, John Isherwood.

Since the Kernow model has not yet been released, it's unlikely. Regards, John Isherwood.

Accepted, if that was what happened - it just amazes me that 'the factory' can depart from the prototype to this degree without having to draw the matter to the attention of the client. Some close examination of contractural duties should, in that case, inform procedures for future projects / contacts. Regards, John Isherwood.