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Having resolved a wiring problem on my grandson's [train wrecker] Bachmann 4f I am 'struggling' to re-assemble it!!  The problem is that the motor runs fine but the wheels wont go round!  I can see that the problem is the connecting rods. To the best of my knowledge I hadn't made any changes to the wheels but something has obviously gone adrift.  Advice please.......glad it isn't a pacific!

55f

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It seems strange that an item that hasn't been disturbed is now causing so much trouble.

 There's no chance the body is now sitting to low or has twisted so the wheels are touching the underside of the body.

  Or could it be you were gripping it by the wheels while working on it and the axle quartering has slipped slightly

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Thanks Londontram......Not the former problem, haven't got as far as installing the body yet, it appears to be the connecting rods which are the problem [?].  although they haven't been touched.

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If the motor runs freely without the wheelks turning, the problem must surely be with the gears - cogs or worm drive not meshing? Is something in that area loose that should be tight?  I am not familiar with the inner  workings of the Backmann 4f but, if something is stuck and nothing is loose, I can't believe the motor would turn.

 

Harold.

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Did you remove the bottom plastic keeper plate that holds the pickup strips to access the wiring?.  If you did, and took the wheels out complete with coupling rods (or they fell out), you might have put them back upside down; this is a mistake I've made more than once!  Bachman final drive gears are offset, so if you replace the wheels upside down/wrong way around the final drive cog will not engage with the cog on the axle; the motor will spin away happily but the wheels are not driven by anything.  If this is the case you can hand push the model and the wheels will turn.  

 

Take the keeper plate back off carefully (there are solder joints between pickups and the feed wires that are delicate) and put the wheels back with the square relief on the crankpin bearings of the coupling rods facing upwards (they represent gravity fed oil reservoirs for horsehair pad that lubricate the bearing).  If the centre axle is the driven one (not familiar with this individual model) then you may have got the wheelset the wrong way around as well.  

 

I get confused between right and left when chassis' are upside down, and a dab of green for starboard and red for port paint (I'm from a nautical family) and on the inside of the keeper plate (other colours are available and you can use what means right and left to you), and on the back of one wheel on each side might be useful in helping to orientate yourself; it will be invisible with the model re-assembled and the right way up.

 

Does the motor run with power to the terminals, and if so does it run with power applied to the rails? If this is the case, the second most likely problem is an electrical connection.  We will assume that track, wheels, and pickups are clean and electrical continuity between them is good.  With a pair of wires carrying power (4-6volts is fine for this) work backwards from the motor terminals.  There will be 2 soldered wires coming to the motor terminals from the DCC board, so apply power here at the DCC board end.  Motor runs?  All well, now the next stage, apply power to the wires from the pickups where they solder connect to the DCC board.  Motor runs?  All well, now the next stage, apply power to the wires where they are soldered to the pick up strips.  Motor runs?  All well, now the next stage, apply power to the pick up strips.  All well?  If the gears engage properly, the loco should run so re-assemble the chassis and track test it.

 

What you have just done is stage process elimination fault finding.  If the motor does not run an any of the stages, you have isolated the location of the dry joint or broken connection you have been looking for.  Resolder it carefully and try again.  Then continue the stage process elimination as you cannot be sure that this was the only dry joint in the sequence.  You can also use this method to determine which side the problem is on; leave one wire connected to the motor terminal and place the other on each point of the other side, then repeat the process with a wire connected to the motor terminal on the second side and place the first wire on the points on the first side.

 

Your loco will, after this procedure, be proven to be fully functional electrically.  If it is not going, then you can look at the wheels and coupling rods, but check that the gears are engaging first, then go through the electrical connection checks.  You will be able to visually check wheel quartering or bends in the coupling rods.  Bent rods can be straightened by hand or replaced if they are too far gone.  Quartering can of course be repaired by twisting the errant wheel back to position, but you will then need to find some way of securing them in this position or they will go out of quarter again.  is it possible that your loco destroyer grandson has driven the loco roughly?  Instant reversals from top speed by flicking the direction switch over or cranking the knob back all the way too quickly are a surefire way to put your quartering out eventually!  When you replace the wheels and keeper plate, make certain that the pickups are bearing on the backs of the wheels correctly for the full width of the sideplay on each wheelset, and adjust them by hand or by levering carefully with a toothpick or cocktail stick.

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If the motor runs and the loco doesn't move then either the gears are not meshing or a gear is loose on its shaft.

The wheels may be in backwards, some models you can fit he wheels the wrong way round. That's the first thing to check.

If the rods are badly enough bent to stop the loco moving the motor should just buzz when power is applied.  If it revs then both the rods are bent and a gear is loose on the shaft.  Sort the rods by taking the motor or idler gear out and tweak the rods so it runs free. Tow it round the layout to check its running nice and free.

That done sort out the loose gear Blob of loctite or maybe a decent superglue will work, it never does for me with plastic gears.

If it still slips try Peters Spares, or Bachmann themselves.

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18 hours ago, The Johnster said:

I get confused between right and left when chassis' are upside down, and a dab of green for starboard and red for port paint (I'm from a nautical family)

Off Topic :jester:
I live near Newlyn, all around is Nautical......
Hearing aids have a Red dot on the Starboard side (Right ear)  and a Green dot on the Port side (Left ear).
I complained to my hearing aid supplier, but they just gave me a glazed look - Specsavers.

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What was the initial wiring problem and what did you do to remedy it?  If we know that it might then be easier to find out what is now wrong.  I note that you said that you hadn't "made any changes" but did you remove the driving wheels at any time?  As far as I'm concerned, if the motor is running fine then it's unlikely to be anything to do with the coupling rods - if they were out of alignment the wheels wouldn't go round and the motor would just jam.  Is the worm gear on the shaft of the motor engaging with the gear on the driving axle?  If it is, is the gear on the driving axle going round when power is applied?  If it is, and the wheels aren't turning, then it's a loose gear wheel on the driving axle.

 

DT

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On 24/06/2020 at 14:51, Penlan said:

Off Topic :jester:
I live near Newlyn, all around is Nautical......
Hearing aids have a Red dot on the Starboard side (Right ear)  and a Green dot on the Port side (Left ear).
I complained to my hearing aid supplier, but they just gave me a glazed look - Specsavers.

 

Audio uses white or black for the left channel and red for the right (yellow for video). I attached appropriately coloured dots to my 'phones.

 

I can never remember whether red/green is port/starboard and whether it is leaving or entering harbour. I thought I finally sorted it onthe ferry to Sardinia, but have still managed to forget. I have the harbour image fixed, but not the colours! (I'd say it was old age, but the problem is not new. I always left exam revision to the last minute or else it would have been a waste of time....)

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1 hour ago, Il Grifone said:

I can never remember whether red/green is port/starboard and whether it is leaving or entering harbour.

Green is (all) right.
Red is the colour of Port (wine).
... and your looking to the Bow (front)
A bit convoluted as a memory jogger, but it works for me.

image.png.e855caf1be2043ed5d41ac94dcfefcab.png

 

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1 hour ago, Steamport Southport said:

I always thought it was

 

Left Hand Down A Bit...

 

:jester:

 

 

 

Jason

Left hand down a bit it is, Lt Phillips sir...

 

 

 

 

CERRAASSHHH!!!

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So did the OP sort it out?  I hate it when someone asks for advice, gets it and then doesn't report back.  Although of course he may have been so peeved by the way his thread has been hijacked that he's just gone away.

 

DT

Edited by Torper
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On 26/06/2020 at 09:23, Il Grifone said:

I can never remember whether red/green is port/starboard

 

The way I eventually managed to remembered it from my aviation days, and it suddenly clicked with me:

 

Left is 4 letters and ends with the letter 'T',

Port is 4 letters and ends with the letter 'T',

As a political party, Labour's colour is Red and is politically left.

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Thanks everyone. I might remember now, but are the harbour lights for entering or leaving? My memory insists the red light was to starboard as we left harbour, but....

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9 hours ago, Il Grifone said:

Thanks everyone. I might remember now, but are the harbour lights for entering or leaving? My memory insists the red light was to starboard as we left harbour, but....

 

Correct!

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Also another way to remember red/green/left/right/port/starboard (in English) it's always the shortest word that matches the left-hand side (red/left/port) and the longest, the right-hand side (green/right/starboard).

 

The French version isn't quite as easy with their tribord and babord as gauche and droite are the same length!

 

Cheers,

 

Philip

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Whenever anyone was stupid enough to leave me with my hand on the tiller, I used to recite "Port Left / Star Bright" whenever someone shouted an instruction.

 

I always thought of "Port" as being red and a bRight star as being green.

 

 

Kev.

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