Squeaking then smoke then it stopped!!

[halsey]

HELP - Bachmann Fairburn Tank DCC issue

 

Please bear in mind I'm not a techy.

 

NOTE It was involved VERY briefly in a derailment short

 

A previously OK loco smoked then stopped then, after taking off the track and taking the body off, and it did run again but failed to respond to controls.

 

Do I assume the decoder (don't know 100% what it is but likely Bachmann EZ 36-553) is faulty or might it be something else which will fry a new decoder - swapping a decoder I can do but not much else or should I send it all away??

 

Would normally use Zimo do you agree

 

All contributions welcome.............

 

Cheers

 

J 

[Geep7]

Ok, looking at the state of that ex-decoder I would guess the most likely cause is when the loco derailed and caused the short, it momentarily exceeded the maximum amp rating of the decoder, which is what allowed the dreaded smoke to escape. If it is the Bachmann EZ decoder you suggest, then the peak rating for that is 0.75 amps. You don't say which DCC system you use, but even the basic systems will deliver more than that if a short occurs.

 

I know they are a bit more expensive, but I tend to always fit my locos with decoders that have at least a minimum amp rating of 1 amp, after I had an issue with a low rated decoder in a Heljan Class 47.

Edited March 2, 2022 by Geep7

[halsey]

13 minutes ago, Geep7 said:

Ok, looking at the state of that ex-decoder I would guess the most likely cause is when the loco derailed and caused the short, it momentarily exceeded the maximum amp rating of the decoder, which is what allowed the dreaded smoke to escape. If it is the Bachmann EZ decoder you suggest, then the peak rating for that is 0.75 amps. You don't say which DCC system you use, but even the basic systems will deliver more than that if a short occurs.

 

I know they are a bit more expensive, but I tend to always fit my locos with decoders that have at least a maximum amp rating of 1 amp, after I had an issue with a low rated decoder in a Heljan Class 47.

 

Thanks - with no knowledge at all to go on that was what I thought - my control system is the Prodigy Advance 2.

 

I have tested the loco on DC and its still fine - it was a very well priced DCC fitted eBay loco bought app 4 months ago.

 

Zimo (MX 600R) decoder (peak rating 1.5 amps) now on order which is fitted on the rest of my stock.

 

Note to self - don't put any locos onto tracks without turning the power off first!

 

J

Edited March 1, 2022 by halsey

[KingEdwardII]

1 minute ago, halsey said:

don't put any locos onto tracks without turning the power off first!

Yes, a useful piece of wisdom. Shorts & electronics don't mix.

 

Yours, Mike

[Nigelcliffe]

Track shorts, such as derailing a loco, should not cause a decoder to fail.     With a track short, there is (or should be) no current running through the decoder, the decoder is outside of the circuit where the short happens.  

 

The type of short which can destroy a decoder is when the motor brushes are connected to one or other rail.  This can happen with some locos where the chassis block is "live".  But such a loco would only work on DCC if the wheels were insulated from the chassis.   Or it can happen with various kit-built locos where there is inadequate insulation between motor contacts and the pickups/wheels/body of the loco.   

 

- Nigel

[NFWEM57]

13 hours ago, Nigelcliffe said:

Track shorts, such as derailing a loco, should not cause a decoder to fail.     With a track short, there is (or should be) no current running through the decoder, the decoder is outside of the circuit where the short happens.  

 

The type of short which can destroy a decoder is when the motor brushes are connected to one or other rail.  This can happen with some locos where the chassis block is "live".  But such a loco would only work on DCC if the wheels were insulated from the chassis.   Or it can happen with various kit-built locos where there is inadequate insulation between motor contacts and the pickups/wheels/body of the loco.   

 

- Nigel

Agree. Almost every deoder failure I have had when converting vintage items to DCC is because of an inadvertent track to motor connection.  I recently converted an original ringfield motor loco and had isolated the motor brushes from the motor body, which is live to track (-), or so I thought.  Turns out the motor shaft was also live and still connecting the (-) track to one of the brushes.  DC operation was fine but a Rails DCC decoder burnt out immediately. Interesting, a LaisDCC decoder I subsequently tried before I discovered the fault simply shut down and remains fully functional.  So, it depends on the decoder.  But I am not sure how  a track short cause a decoder failure, there might be something else in the loco causing a short from motor to track, even a slither of wire can do that.  Might be a good idea, with the decoder removed, to check for conductivity between the wheels and the motor - it should be an open circuit.  And do a close visual inspection around the circuit boards and pickups.

[halsey]

42 minutes ago, NFWEM57 said:

Agree. Almost every deoder failure I have had when converting vintage items to DCC is because of an inadvertent track to motor connection.  I recently converted an original ringfield motor loco and had isolated the motor brushes from the motor body, which is live to track (-), or so I thought.  Turns out the motor shaft was also live and still connecting the (-) track to one of the brushes.  DC operation was fine but a Rails DCC decoder burnt out immediately. Interesting, a LaisDCC decoder I subsequently tried before I discovered the fault simply shut down and remains fully functional.  So, it depends on the decoder.  But I am not sure how  a track short cause a decoder failure, there might be something else in the loco causing a short from motor to track, even a slither of wire can do that.  Might be a good idea, with the decoder removed, to check for conductivity between the wheels and the motor - it should be an open circuit.  And do a close visual inspection around the circuit boards and pickups.

 

Your suggestion is slightly beyond my capabilities but I can try the basics I have a multimeter and do know how to use its basic functions to check connectivity I assume an open circuit is one that isn't connected??

 

Is the fact that it seems perfectly OK on DC relevant to your concerns/questions?

[Trainshed Terry]

15 hours ago, Geep7 said:

I know they are a bit more expensive, but I tend to always fit my locos with decoders that have at least a maximum amp rating of 1 amp, after I had an issue with a low rated decoder in a Heljan Class 47.

I have a 5 Heljan 47, and I have always put a DCC chip with a rating of 2 AMP peak rating. as they are heavy loco and the trailing load could make them  go over the peak rating of a 1 amp chip.

 

Terry.

[Nigelcliffe]

37 minutes ago, halsey said:

 

Your suggestion is slightly beyond my capabilities but I can try the basics I have a multimeter and do know how to use its basic functions to check connectivity I assume an open circuit is one that isn't connected??

 

Is the fact that it seems perfectly OK on DC relevant to your concerns/questions?

 

The types of failure discussed are unlikely on a loco which comes with a DCC socket fitted.  If you saw the loco previously running on DCC, then the loco was wired correctly at the factory (wiring fault leading to decoder failure would be instant).   
 

 

The next most likely failure for an 8-pin socket is the pins of the decoder going through the socket and touching the chassis.  Look as to whether this was possible, and if remotely likely, try to either raise the DCC socket slightly (small plastic washer to lift the PCB?), or put some insulating tape below the socket on the chassis.  

 

(If you haven't seen the loco running on DCC, then we need to go back a step and check the loco wiring, which is a different problem.  A loco can run correctly on DC with a blanking plug and, if wired wrongly, destroy DCC decoders. Such wiring mistakes at the factory are rare, but do happen.). 

[halsey]

21 minutes ago, Nigelcliffe said:

 

The types of failure discussed are unlikely on a loco which comes with a DCC socket fitted.  If you saw the loco previously running on DCC, then the loco was wired correctly at the factory (wiring fault leading to decoder failure would be instant).   
 

 

The next most likely failure for an 8-pin socket is the pins of the decoder going through the socket and touching the chassis.  Look as to whether this was possible, and if remotely likely, try to either raise the DCC socket slightly (small plastic washer to lift the PCB?), or put some insulating tape below the socket on the chassis.  

 

(If you haven't seen the loco running on DCC, then we need to go back a step and check the loco wiring, which is a different problem.  A loco can run correctly on DC with a blanking plug and, if wired wrongly, destroy DCC decoders. Such wiring mistakes at the factory are rare, but do happen.). 

 

It was all OK before this "incident".

 

I will look below the PCB as you suggest

 

Thanks

 

J

[Geep7]

35 minutes ago, Trainshed Terry said:

I have a 5 Heljan 47, and I have always put a DCC chip with a rating of 2 AMP peak rating. as they are heavy loco and the trailing load could make them  go over the peak rating of a 1 amp chip.

 

Terry.

Very sound advice for a Heljan 47.

 

I did mean to put minimum, rather than maximum, of 1 amp, autocorrect must have got me there. Have changed the post now.

[halsey]

HELP needed again - how do I know which way round to fit the new decoder 8 pins fully symmetrical - I cant see any clue/guide?

 

J

[smokebox]

Pin 1 (orange wire) should be indicated by a mark of some sort, such as the number 1 or a small triangle on the socket pcb.

If not, it doesn't matter which way round you fit the decoder - no damage will be done if it's the wrong way round but any lights that are fitted won't work.

[halsey]

46 minutes ago, smokebox said:

Pin 1 (orange wire) should be indicated by a mark of some sort, such as the number 1 or a small triangle on the socket pcb.

If not, it doesn't matter which way round you fit the decoder - no damage will be done if it's the wrong way round but any lights that are fitted won't work.

 

All good thanks - there was a triangle 95% hidden by a coil - all running well now.

 

Thanks all

 

J

[halsey]

I've still got the bl**dy squeak!!

 

Everything else is back to normal - but the squeak is still there, it seems to be echoing in the body but it is still there when the body is off.

 

It is rhythmic but doesn't vary much with speed changes.

 

I've tried careful oiling with the right oil but to no avail - can I spray WD40 on the wheel mechanisms rods/pistons etc (I'm sure these must have generic title but apologies I don't know it).

 

Or is a general application of WD40 a no no - I'm guessing it is but what else can I try.

 

Its a loco I use a lot and its really annoying.

 

I have a video with sound which shows the problem - PM with your email and I can send it if you are up for a bit of diagnostics!!!

 

Edited March 6, 2022 by halsey

[Dagworth]

14 minutes ago, halsey said:

Or is a general application of WD40 a no no

Don't let WD-40 anywhere near any part of a model railway

[halsey]

1 minute ago, Dagworth said:

Don't let WD-40 anywhere near any part of a model railway

 

I guessed - and I haven't ever!

[halsey]

Hi,

 

Finally - I have improved the squeak!! - after a lot of "googling" I came across an old post from USA saying its very rare but "wiper" pick ups can sometimes squeak and to sparingly apply conductive grease to the inside (pick up face) of the wheels - it has improved it a lot and it probably needs to run it in now but I thought I'd pass on the tip

 

Nevertheless I have decided to return it to DC and put it on flea bay when I have found a replacement - its a superb runner but any and all squeaks drive me mad (ask SWMBO) even faint ones, I guess there must be a touch of OCD in me!

 

If any of you have the skills to replace the wiper pick ups (which I don't) it would be a very nice loco to add to your stable - PM if interested it does run very well.

 

Cheers all.

 

J

Edited March 9, 2022 by halsey