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B12 not working


Lujadris

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I am trying to get an old Hornby B12 from The Anglian set (R1089) working again after 10 years without being used. At first the only the worm connected to the motor would work however this was down to a worn out worm gear, which I have now managed to replace. Despite this replacement, I now can't seem to get power from the track to the motor. I have tested out the motor separately and it works fine, and I can even detect power in the wheels of the loco by placing the motor wires on the wheels. But despite this, the pickups won't pass the power through as when I try connecting the motor to the pickup connection wires, nothing happens. I have taken the pickups off and on again, and can see they are all touching the wheels but still nothing. The wires connecting to the pickup plates are also intact. Any advice?

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Obviously there is a break in the power path between the wheels and the motor. If you stripped down this loco and during the strip down you removed the wheels and axles. Then you have possibly put one or all of them back the wrong way round. Some (many) models only work when the wheels are fitted the right way round.

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All of these type of diagnostic testing methods are immensely enhanced if you invest in a cheap multimeter (less than £8 delivered on ebay) to measure voltage, current and resistance. Without a meter, you are poking about in the dark wearing a blindfold.

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See also – further TIPs on how to get the best user experience from this forum.

https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/

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This is a China made B12.

 

I seem to recall that all the wheels have plastic centres, so are all insulated.

 

The pick up plate has contacts for both sides of the loco.

 

There are two wires from the pick up plate, to the motor.

 

It "should" be a simple thing, but in life nothing is simple...

 

Any photos?

 

It may help if someone else can see what wires are where?

 

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@ Sarahagain & Lujadris :- Interesting I have 2 B17 (1 is  No. 61619 - Wellbeck Abbey & the other is No. 61672 - West Ham United (& no I'm not into Football!!!)) & I've just done the 'battery test' (that is where you put a 9 V square battery to the Wheels)

Where there is a red cross - means that there are 'no pickups' & the blue circle just shows where the wire is from the Loco to the Tender!!!

 

/media/tinymce_upload/a0da76a7179913be511b3ee164fd4cb0.JPG

 

The 'Wellbeck Abbey" has more 'Pickups' than the "West Ham United"!!! The pickup wires are just inside the wheels on both Locos & tender -look closely!!! 

 

Hope this Helps  😀

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Thanks all. 

@Sarahagain - I agree it should be simple so I'm very confused. I have checked both the motor and pickups plates separately and they definitely work. I tested the pickups by taking them off the chassis and passing a current them whilst touching the motor wires, which resulted in it working fine. But then when putting the pickups back onto the chassis, the current doesn't get through, despite the pickups appearing to make contact with the wheels. I should point out, when initially testing various methods, the motor would work when connecting its wires directly to the driver wheels, but this now doesn't seem to work. /media/tinymce_upload/3090e877ca0292879185d242e9b52d14.jpg/media/tinymce_upload/2d09c66658ec2671dfa8397ce0f9b086.jpg

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Cleaning contacts is certainly a good idea. Although a very different loco I put a brand new 8F in storage many years ago and despite running well before it would not move. I found that all the contacts had tarnished to a dull brown.

 

After cleaning all works well.

 

Another thing is that the tollerence is quite tight on these China made locos so make sure the contacts are rubbing on the right part of the wheel. After stripping down a 4-4-0 County I had a great deal of trouble getting power from one of the wheels just becaus the pickup had been bent.

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Unfortunately it appears my post with photos has yet to be approved by moderators. Not sure if its relevant but every time I put the chassis (without the motor) on the live DC rails, it keeps making a popping sound as if something is going on with the electricity. No idea what this however one other issue I have come across is the pickup plates. According to the service sheet for the loco (http://www.hornbyguide.com/service_sheet_details.asp?sheetid=274) the left and right driver wheels pickup plates should be separate, with the right wheels plate sitting above the folding plastic mount and against the bottom of the chassis. Would this be anything to do with the issue I'm facing?

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Unfortunately it appears my post with photos has yet to be approved by moderators.

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Moderators can't approve photos ... approval is performed by Hornby admin and they are in lockdown at present.

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If both metal pick up plates are together, there is a very good chance that they may touch, and cause a short circuit, which will make the controller cut the power.

 

That would stop the motor from running...

 

It may also be the shorting current making the "popping" sound.

 

The two plates are spaced as in the Service Sheet illustration to avoid them touching each other.

 

By the way, the backs of the pick up wipers are painted black, to make them less conspicuous from the side view.

 

Some parts of the front of some wipers are likewise painted black.

 

/media/tinymce_upload/63081d6d1588c918fc0c3e3845ce5778.jpg

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It may be the camera angle but in the lower photograph the front of the bottom righthand wheel looks to be extremely close to the chassis block - is it making contact?  A short circuit could be occuring.  The back to back distances between the wheels should be 14.5mm.  And something is amiss with the crank pin on the top lefthand wheel.

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It may be the camera angle but in the lower photograph the front of the bottom righthand wheel looks to be extremely close to the chassis block - is it making contact?  A short circuit could be occuring.  The back to back distances between the wheels should be 14.5mm.  And something is amiss with the crank pin on the top lefthand wheel.

I have only removed the two wheels connected to the worm gear therefore the wheel you mention should be in its original location. It doesn't seem to be making contact. I think the crank pin in the other wheel isn't screwed on properly therefore I'll take a look. This is one of the wheels we took off to replace the worm gear.

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If both metal pick up plates are together, there is a very good chance that they may touch, and cause a short circuit, which will make the controller cut the power.

That would stop the motor from running... 

It may also be the shorting current making the "popping" sound.

The two plates are spaced as in the Service Sheet illustration to avoid them touching each other.

By the way, the backs of the pick up wipers are painted black, to make them less conspicuous from the side view.

Some parts of the front of some wipers are likewise painted black.

So I've tried sticking to the service sheet and have the two pickup plates separate, with one of them sitting on top of the folding piece of plastic and up against the bottom of the chassis. Is this correct or should the two plates be inside the folding plastic, just separate?

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When mounted, is it possible the metal 'wiper strips' have moved and either / both are touching the mount screws?

Does this locomotive have a speedo cable - just curious there appears to be a spacer on one of the driven drivers - coupling rod should be under, not over the spacer. Won't affect this issue, but may put some strain on the rod.

 

Al.

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My recollection is that both pick-up strips should be sandwiched within their plastic carrier so that neither comes in to contact with the chassis - both parts of the plastic carrier having opposing cut-away sections to accommodate the two pick-up strips whilst keeping them apart.  As Al says, check that they have not moved during reassembly to come in to contact with either of the securing screws.

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