Basic numpty question
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joshing_man
- Posts: 1217
- Joined: Sun Dec 04, 2005 9:23 pm
- Location: High Wycombe, England
Basic numpty question
I am selling some locos etc for a friend. Another friend bought a Harry Potter set (unused) but the loco doesn't move. I have tested it and the motor is working but not driving the wheels. I tested wire directly to the wheels and they did move. Back on track nothing. So what appears to be the issue as far as getting the power to turn the wheels when on the track? Anything I can do to rectify it? Help appreciated!
The Original Smiling Man With Train (SMWT):
Re: Basic numpty question
Bear in mind I have never looked at this particular item; so what I suggest is based on general knowledge of Hornby mechanism construction and typical causes of failure.
The good news is that the motor runs when it gets power.
However, the motor won't turn the wheels with the loco on track, but did move the wheels when power was applied directly to the wheels.
This indicates a fault somewhere in the gear train, which only becomes evidentwhen the mechanism is not having to move the whole loco's weight.
Top three problems to look for:
The gear on the driven axle is slipping on the axle; possible causes the gear boss is split so not gripping well on the axle splines, the axle splines are too shallow, so don't secure the gear boss to the axle. With the loco on track and no power supplied, what happens if you push the loco? If the driving wheels turn then this is top suspect. You will then need to take the keeper plate(s) off to 'take a look'. If this proves to be the the case replacement parts are required.
If that isn't the problem then check if the axle gear is positioned so it barely meshes with the idler gear above it, and can move out of mesh with the idler gear when load is applied, because both gears have some freedom to move sideways. (It needs a good light to peer inside the chassis slot containing the gear train.) Usually moving the axle gear to centre it on the axle so it will stay in mesh does the job. If the axle gear then slips then parts replacement as above.
Finally it could be motor is not well secured, and the worm pushes itself out of mesh when enough power to move the loco is required. With the loco body off, hold down the cover over the worm and see if the motor turns the wheels with track power applied. Fixing this may be as simple as holding down the worm cover and slightly tightening the retaining screw - gently does it - but if that doesn't hold gluing the motor down with Evstick has been an effective cure for me. Give the adhesive 48 hours to go off before running the model.
The good news is that the motor runs when it gets power.
However, the motor won't turn the wheels with the loco on track, but did move the wheels when power was applied directly to the wheels.
This indicates a fault somewhere in the gear train, which only becomes evidentwhen the mechanism is not having to move the whole loco's weight.
Top three problems to look for:
The gear on the driven axle is slipping on the axle; possible causes the gear boss is split so not gripping well on the axle splines, the axle splines are too shallow, so don't secure the gear boss to the axle. With the loco on track and no power supplied, what happens if you push the loco? If the driving wheels turn then this is top suspect. You will then need to take the keeper plate(s) off to 'take a look'. If this proves to be the the case replacement parts are required.
If that isn't the problem then check if the axle gear is positioned so it barely meshes with the idler gear above it, and can move out of mesh with the idler gear when load is applied, because both gears have some freedom to move sideways. (It needs a good light to peer inside the chassis slot containing the gear train.) Usually moving the axle gear to centre it on the axle so it will stay in mesh does the job. If the axle gear then slips then parts replacement as above.
Finally it could be motor is not well secured, and the worm pushes itself out of mesh when enough power to move the loco is required. With the loco body off, hold down the cover over the worm and see if the motor turns the wheels with track power applied. Fixing this may be as simple as holding down the worm cover and slightly tightening the retaining screw - gently does it - but if that doesn't hold gluing the motor down with Evstick has been an effective cure for me. Give the adhesive 48 hours to go off before running the model.
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joshing_man
- Posts: 1217
- Joined: Sun Dec 04, 2005 9:23 pm
- Location: High Wycombe, England
Re: Basic numpty question
Thanks Bigmet
When no power applied I can simply push the loco around the track with no friction. It has been a while since I have run any locos but I expected friction from the driving wheels.
That would point to your first stated problem being in the issue? The gear on the driven axle is slipping on the axle; possible causes the gear boss is split so not gripping well on the axle splines, the axle splines are too shallow, so don't secure the gear boss to the axle. With the loco on track and no power supplied, what happens if you push the loco? If the driving wheels turn then this is top suspect. You will then need to take the keeper plate(s) off to 'take a look'. If this proves to be the the case replacement parts are required.
Anderew
When no power applied I can simply push the loco around the track with no friction. It has been a while since I have run any locos but I expected friction from the driving wheels.
That would point to your first stated problem being in the issue? The gear on the driven axle is slipping on the axle; possible causes the gear boss is split so not gripping well on the axle splines, the axle splines are too shallow, so don't secure the gear boss to the axle. With the loco on track and no power supplied, what happens if you push the loco? If the driving wheels turn then this is top suspect. You will then need to take the keeper plate(s) off to 'take a look'. If this proves to be the the case replacement parts are required.
Anderew
The Original Smiling Man With Train (SMWT):
Re: Basic numpty question
It's most likely the axle gear loose on the axle if it rolls pretty freely. You need to take keeper plates off the underside to check it out, unless it happens to have the axle gear exposed on the underside. If the axle gear is 'locked' by the worm gear but the wheelset spins that's the trouble. If it's still in warranty it can be returned faulty, otherwise it's a replacement piece from Hornby. To be brutally frank I don't know whether spares can still be sourced from some Hornby retailers, or if all spares are now obtained directly from Hornby, hopefully there will be information on their website.
Re: Basic numpty question
If it turns out you do need spares this place may well be able to help (nice new shiny web site and all!). Peter's Spares https://www.petersspares.com/