7mm Problems with my Heljan 31

[Osgood]

If you are having pick-up problems on the 31's it could be because the pick-ups are made of a too smaller gauge phospher bronze wire and they might not be making contact with the screw tab which the wire is connected to. Howes has a supply of the correct gauge pick-ups for these models,

The issue Brian has highlighted above is simply one of poor connection of pick-up wire to the wiring loom.

Larger dia. wire will correct this but does it do anything else to improve pick-up integrity? I imagine the greater pressure on contact between pick-up and tyre would help to keep this vital area clean, but what about increased resistance to rolling - is this anything to worry about?

I bought my 31 through a Main Dealer, so after reading the above I contacted them to enquire about pick-up issues and (out of loyalty I suppose ) to see if they could supply remedial parts. They said that of the very significant quantity of 31s they had sold, they had received not one complaint about pick-ups. And their only Heljan pick-up problem concerned a Class 37 for which a stock replacement part was issued.

Now - of course it may be that all those sold were to buyers like me who have kept them in their boxes ever since , or that their customers do not bother to contact them re. issues, or that Howes received a faulty batch of 31s.

I'm now getting close to being able to power up both DCC and non-DCC locos on a 2m test track, so in light of this thread the first thing I'll do is check all pick-ups are working correctly.

So my question is - if I check the integrity of each pick-up wire to loom connection and it proves to be good, is there any point in installing these thicker pick-ups? And is there a simple way (e.g. solder or additional wire packing) of rectifying any poor joints?

 

[Steph Dale]

Erm, dunno.
But, the contact area is small and, as bought, the loco only picks up on eight wheels. As the pick up grooves are in the back of the 'dead' wheels converting the loco to all wheel pick up looks to be relatively straightforward. I've not done mine yet, but is on the to do list when I pull the model apart for detailing.
Steph

 

[richard carr]

I doubt most people realise there is a problem as the issue with the pick ups only shows itself under load on DCC, running light engine the loco works fine even with the poor pickups. I haven't tried it on DC

I tried both mine with a train of 3 JLTRT GUVs without any additional weight, a heavy slaters southern GUV with lots of lead in it, 2 JLTRT CCTs and a slaters BY again with plenty of weight in it, it was run on a layout 42 feet by 25 feet, it couldn't cope with that.
I also tried on my 10 ft test track with 8 JLTRT TTA tank wagons (these are really heavy) it struggled with those, and by this I mean that light engine it would happily run over the full length of the track, but with the wagons it would buffer up then move about 6 inches then start to stutter and stop, give it a nudge it would move another inch then stop and so on, take the wagons away then it would run fine again.

Most people probably don't realise there is a problem because they have only run theirs on their own. I haven't tried mine under dc so I don't know if the say issue arises but I have a third one in a box that I will try when I get home next weekend and see how it works. I also suspect that most of these locos sit their boxes and hardly ever come out to play. My 3rd 31 came from Ebay who ever had had it certainly looked after it well, I doubt it had ever been out of its box.

Howes know there is problem because the only spare pickups available are for a class 31,


Richard

 

[Osgood]

Thanks for the clarification Richard - most helpful. Hopefully your problem will be cured with the new pick-ups, l look forward to your report!

Tony

 

[richard carr]

I fitted the new pickups this morning and I have to say that they do make a significant difference.

Looking at a Deltic it too has thin pickups but I will need to remove the bogie sides to check the precise thickness.

Richard

 

[OzzyO]

Coming in to this thread a bit late, if you had an ammeter in the circuit (would one work with DCC?) It my have helped show up the problem earlier by showing that the loco was drawing more or less power. It may have shown that the loco was drawing a lot of power at one point on the layout, with or without a load.
If I'm having a problem with a loco it's one of the first things that I look at if it starts to draw a lot of power some thing is going tight. If you use the needle type it can show up tight spots in the valve gear in each rev.

OzzyO.

PS. electrics in not one of my strong points.

 

[Osgood]

......PS. electrics in not one of my strong points.

I'm very much an ammeter at electrics too.

 

[Steph Dale]

...if you had an ammeter in the circuit (would one work with DCC?)

Paul,
Not unless it was pricey - you'd need to be measuring current flow in an AC circuit (tricky/pricey) that's not at 50Hz (really tricky/pricey!).
Worth also noting that an ammeter set up like that would tell you how much current the drive + decoder was pulling, so wouldn't quite give you an clear view of whether/how/how much the motor(s) were loading up. It would be a fair indicator though.
I agree with you about using an ammeter to check the performance/free running of a loco; it's a useful check before installing a decoder. Apart from anything else it helps selecting a decoder of the right current output. On a DMM you have to look at the values displayed (unless you have a peak/min hold function) to see where the tight spot is. It's much easier as you say with a galvanometer where you can just look the needle swinging back and forwards in sympathy.
Steph

 

[OzzyO]

Told you electrics was not a strong point of mine

 

[richard carr]

If you use an NCE powercab as your DCC controller it will display the current it is putting out. The 31 draws about 250m amps running light engine and about 750 with a heavy load.

RIchard

 

[richard carr]

I managed to do some more testing at the weekend and I have to say that the problem has improved but is still not fully cured. Scale7 JB was there to observe and we both concluded that the loco kept shorting out briefly at higher speeds (speed step 40 and above) this isn't that noticeable as the fly wheels keep the loco moving but its a pain at lower speeds and the sound of course cuts out.
We also tested a DC loco and it ran fine on DC.

 

[taliesin]

I freely admit to being a complete dud when it comes to electrickery, however i have heard in the past that Heljan motors are not particularly well matched, could this exasperate the problem? cheers Rob

 

[iploffy]

On DC I Don't think there is a problem, I recorded it

 

[taliesin]

Gotta luv that freight train , excellent stuff, cheers Rob

 

[richard carr]

The problem has finally been solved.

The motor wires are held against the the motor by a cable tie. The cable tie is done up so tight it has crushed the mtor wires to the point where there is bare wire touching the case of the motor, now that has been insulated the loco is running perfectly as it should. Both my 31s have this problem both now run fine.

Richard

 

[iploffy]

something so simple can cause so many little problems that can lead to very costly, drastic measures

 

[Steph Dale]

The problem has finally been solved.

The motor wires are held against the the motor by a cable tie. The cable tie is done up so tight it has crushed the mtor wires to the point where there is bare wire touching the case of the motor, now that has been insulated the loco is running perfectly as it should. Both my 31s have this problem both now run fine.

Richard

Fantastic news - and thanks for letting us know!
I'll have to give mine a quick check ASAP...

Steph

 

[richard carr]

It certainly can. I would recommend that everyone should check all their recent heljan locos, Deltics, westerns and 31s, possibly others as I'm not sure when the introduced the cable tie, I know its fairly recent as the 37s don't have it. I'm certainly going to check all of mine, both my Deltics exhibit similar problems but to a less obvious extent.

 

[richard carr]

It has been so frustrating I even fitted an NCE 8amp decoder to one other 31s this evening and that was shorting the layout all over the place, it has certainly been worth fitting a powershield to the layout to limit the current to 3.8 amps.

 

[Osgood]

Richard - I note from an earlier post that you fitted the heavier gauge pick-up wires before you discovered the motor wire fault. Given the cause of the fault, are you still of the view that this is a beneficial modification?

Tony