A limited DC controller test

Discussions of the prototypes and how to model them. Show us how you do it.
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A limited DC controller test

Postby nigelcliffe » Sat Mar 05, 2016 5:30 pm

Following the failure of one of Coldfair Green's Pentrollers, I have been seeking something to replace it. Having assembled a selection of devices, most of them borrowed, a test session was undertaken last night. What others might draw from this may be limited, are your locos built in a similar way to those we tested ?

The test loco was a J72, with a Mashima motor and, I think, Romford gears. It probably has the slightest of mechanical tight spots, so some controllers will show this up with surging, which in turn, causes a train of wagons to bump back-forth. Its a regular runner on the layout.

Pentroller Handheld.
We've found two of these in the last month by asking around. They are difficult to find having not been made for more than 20 years.
Starting and stopping control is very good. Continuous medium speed running is good, with the loco quiet and the wagons behind not bumping back-forward as the loco changes speed.
Shape in hand is good for one-handed operation. Coil lead is nice, though a little short (we have a coil extension lead which helps).
Of the DC controllers tested here, by far the best.

Modellex boxed "handheld".
These are quite cheap at well under £30.
Starting and stopping is OK, though not as smooth as the Pentroller. There is a large dead-area on the speed knob before any movement. Continuous medium speed sees the loco running quietly. There is a little hint of surging from the motor, and some sign of bumping of stock.
Its not the nicest box to hold, being quite large and rectangular. Shape needs two handed operation.
Overall verdict, quite good for a cheap controller, if it were in a better shaped case it might be much nicer to use.

Medvend handheld.
These are tiny units designed for either 9v DC battery or a DC power pack. Cheap, at around £25 (price varies as its from Hungary and priced in Euros). A quick test using a 9v battery as power supply showed it to be too slow, but with a 12v DC supply it gave a more reasonable output.
Slow speed starting and stopping good, approaching Pentroller, but loco has distinct buzzing from the pulse-width waveform. Medium speed stability better than Modellex, though faint buzzing apparent.
Shape, its tiny and the arrangement of controls is unusual with speed knob on side, direction on front. With an external power supply its a bit messy to hold, and I'd be tempted to re-package the insides and fit a combined four-wire lead (similar to other devices) from the base, sacrificing the battery space.
Overall verdict, interesting and maybe worth having. Buzzing from the PWM raised some questions.

Pictroller handheld.
These are claimed as a Pentroller replacement. Quite expensive compared to the other two controllers, at £65. Includes some inertia/braking features not present on a normal small Pentroller handheld.
Slow speed starting/stopping is poor. There is a distinct lag and/or dead area in the start of the controller, and it proved impossible to make really smooth starts. Turning on the inertia feature improved the starting somewhat, but then it was impossible to nudge a loco back a tiny distance to slacken couplings (something we need fairly regularly on Coldfair Green). Stopping was similar to starting, smoother with inertia turned on, but then difficult to predict/control.
Mid-speed control seemed to amplify the tight spot in the loco, with the surging in speed being more pronounced and the wagons bouncing off the buffers as a consequence.
Case shape is nice (same as Pentroller), though lead is not as good, being a straight cable rather than the spiral cable of the Pentroller.
Overall verdict: case shape is nice, control is disappointing.

So, from those tests, if pushed into buying a replacement, either of the two cheaper options would do, though its a step down from the control we're used to. Pictroller is not a good choice for us. We're very relieved to have found genuine Pentrollers to replace the failed example for the analogue locos we have for the layout.

We then swapped locos to a J65. This is a fairly old loco with a lot of miles under it. Mashima motor, Romford (or similar) gears. Fitted with a DCC decoder. Compared to analogue, control is a lot better, can stop/start more smoothly. This is an average DCC chip from TCS, so could be better with a high-end chip, stay alive capacitors, and the like. Conclusion from this limited test, DCC is worth it, particularly with good DC controllers being difficult to find.

- Nigel

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Tim V
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Re: A limited DC controller test

Postby Tim V » Sat Mar 05, 2016 6:10 pm

The lack of development in DC controllers is symptomatic of the way that the future of control is going. There is no incentive to create new decent DC controllers.

I understood the Pentroller was flawed, with potentiometer failures common. Certainly it was one of the reasons I moved on to other forms of control.
Tim V

Philip Hall
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Re: A limited DC controller test

Postby Philip Hall » Sat Mar 05, 2016 6:31 pm

I have used an old AMR handheld, which was supplied with the feedback turned down a bit, for twenty or more years. I have another which threw in the sponge a while back, but I think I may have found someone who can repair it. Its one drawback is a slight increase in noise compared to some others, but it runs most things, including the combination that Nigel writes of (and some more antique ones as well!) pretty smoothly.

I like the handheld Pentroller, and with some engines, the panel mount version. Similar results to the AMR with less noise and a slightly less certain start.

I agree completely about the Pictroller having had one on loan for a while and have no inclination to invest in one.

I actually quite like the Modelex, apart from its bulk, and it was recommended to me by Roy Jackson so I guess reliability is not in doubt here. Engines run very quietly but I have not experienced the hunting Nigel mentions. Another one I have used is the Gaugemaster (cream panel) handheld, similar results to the Modelex.

Tim is quite right, things have moved on, and probably DCC is the way forward, but there are still some of us out here who really do not care for any kind of computerisation of our railways. I use a computer, of course I do, but sometimes (more than I would like) it is a source of frustration and irritation which is what my hobby is supposed to take me away from! And then there's the cost...


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Re: A limited DC controller test

Postby Horsetan » Mon Mar 07, 2016 6:11 pm

You could, of course, build your own.... ;)
That would be an ecumenical matter.

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David Thorpe
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Re: A limited DC controller test

Postby David Thorpe » Mon Mar 07, 2016 6:17 pm

Have you tried Morley controllers? You don't hear much about them but they seem to have been around for a long time and certainly look pretty good - http://morleycontrollers.com/ I've no experience of them myself however.


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