Bachmann Jinty - Is this DCC Fitted or not?

[Penlan]

First - I know NOTHING about DCC,
But I have reputation? for resolving model railway problems in our Village 

I have been asked to look at a Bachmann Jinty Chassis, because it's shorting?
The owner assures me it's (set) in a DC mode.
However comparing a photo on Google with the one I've been handed,

I'm tempted to say it's fitted with a DCC chip and should be on a AC supply from the track.
Any guidance is welcome, before I start putting a meter etc., across everything.
Photo's : The Chassis I've been handed and then the chassis on Google:

 

[WIMorrison]

Not DCC Fitted, but DCC Ready - that is a blanking plate which is removed to enable you to fit a DCC decoder. It is there to allow the loco to run on DC

[Penlan]

Many thanks.
Better to ask than have to replace it....
The plate just looked different to the Googled image.
Right, now to find the short... 

[Pete the Elaner]

As above. The blanking plate which joins the connections which need to be intercepted by the decoder. (Red for track to orange for motor & black for track to grey for motor).

I have had one plate which could be pushed in too far, due to the socket being a little too close to the chassis (or the blanking plate having pins slightly too long - it depends on your point of view doesn't it!). The pins therefore touched a piece of metal below, causing a short. The easiest way to troubleshoot this is to ease the plate out very slightly.

 

As the 2nd illustration shows. The blob of solder connects the end 2 pins together. These provide the connection from wheels to motor. The blob extends to a side pin for lighting. The solder blobs indicate this is a Bachmann blanking plate.

The 1st illustration looks like a Hornby blanking plate. These appear to be finished with a little more finesse (but do the same job, so is this really important).

[Penlan]

1 minute ago, Pete the Elaner said:

I have had one plate which could be pushed in too far, due to the socket being a little too close to the chassis (or the blanking plate having pins slightly too long - it depends on your point of view doesn't it!). The pins therefore touched a piece of metal below, causing a short. The easiest way to troubleshoot this is to ease the plate out very slightly.

Many thanks, I will check that too. 

[Penlan]

Uhmn...
I eased out the blanking piece  - no change.
The resistance is around 0.9 ohms, so nothing in the way - Short Circuit.
Take off the blanking piece, all's well across the wheels, with the blanking piece off the loco.
I also took out the screw retaining the small circuit board to check there's no metallic fly's behind it, nil.
I put a meter over all the pins, as I felt I should , 

and with the pins numbered as follows, with the word DC at the top of the blanking piece
1....2

3....4

5....6

7....8
Numbers 4 & 5 were the only ones that did not connect with any other pins, or each other,

all the rest had around 1 ohm resistance (no resistance) in any combination.
I don't know the history of the loco, presumably the owner hasn't just bought it,
otherwise it should go back under warranty 
It seems to me I should be telling the owner "get another Blanking Piece and try it".
He can get one from Kernow Models presumably, they are our nearest shop, only 20+ miles away.
Again I'm grateful for any advise.

Edited September 12, 2020 by Penlan

[Pete the Elaner]

With your diagram pins 4 & 5 will do nothing on a small steam loco.

Neither will 2 & 6 - these are usually used for directional lighting.

1 & 8 are for motor connections. 2 & 7 should go to the track. The blanking plate should connect 1 with 2 & 3 and  & 7 with 8 & 6. For a loco with no lighting, you do not need any connections to pins 3 or 6. Some newer decoders also include a suppression capacitor. It is better here than elsewhere in the loco because decoders work better without suppression elsewhere.

 

With 12v, a resistance of 1 ohm will allow 12 amps, which will cause an overload. Definitely a problem. Resistance across sockets 1 & 2 and also across sockets 7 & 8 should definitely be infinite with the blanking plate removed.

I think the issue is less likely to be the socket itself & more likely to be untidy soldering/connections underneath.

 

I agree with you about questioning where this has come from.

I hope you manage to get to the bottom of it.

[34theletterbetweenB&D]

I'd be looking at the soldering underneath the board as @Pete the Elaner suggests. Bachmann are - in my experience of their product - pretty consistent in the use of a grey and murky pinky-brown insulation for the motor connections. So I'm wondering how that blue wire got there...

[Grovenor]

I would remove the black square surface mount component from the blanking plate which could be shorting pins 1 & 2 to pins 7 & 8. See what happens without it. Its not needed anyway as there are loads of supplression capacitors on the motor.

[Butler Henderson]

Would suggest the pins to the rear of the socket are touching the vertical metal motor support  - there is no way you should get a short on pins 3 and 4 and that would explain the other shorts. Electrically the model is relatively simple as the motor wires are connected directly to the socket pcb - I have had  dcc shorts on  Bachmann model where the motor and pick up circuits are routed via metal strips and  soldered wires had excessive solder on joint shorting the one of the motor circuits to a pick up circuit. 

[Graham Radish]

9 hours ago, 34theletterbetweenB&D said:

I'd be looking at the soldering underneath the board as @Pete the Elaner suggests. Bachmann are - in my experience of their product - pretty consistent in the use of a grey and murky pinky-brown insulation for the motor connections. So I'm wondering how that blue wire got there...

Thats one thing that gets on my t**s with Bachmann, their colour coding of wires makes no sense and does not follow the NMRA specs whatsoever. my 37 has brown grey and black for the headlights. and without a multimeter you can blow the sound decoder instantly.

Edited September 13, 2020 by Graham Radish

[Penlan]

My apologies for not coming back sooner, a small matter of the death of a close friend and arranging the funeral etc.,.

I asked the owner of the loco if he had a spare blanking plate, Yes.
He dropped it round to my place sometime last week.
I had been wondering when he was going to do it, but as above, I had other things on my mind.
Whilst having coffee this morning with my 97 year old Mother-in-Law, I noticed on her window-cill, a blanking plate.
I deemed it better to quietly remove it, rather than set up a "Why is it there.." situation, she has dementia and probably some other age related condition(s) too.
Plugged it and "Hey-Presto" all's well with DC.... 

I've phoned the owner, apologised for the delay, and told him he can collect.
Many thanks again for you guidance.
IF it had been my loco, and because I'm a DC dinosaur, I would have stripped all the gubbins off and wired the pick-ups directly to the motor   

[kevinlms]

14 hours ago, Penlan said:

My apologies for not coming back sooner, a small matter of the death of a close friend and arranging the funeral etc.,.

I asked the owner of the loco if he had a spare blanking plate, Yes.
He dropped it round to my place sometime last week.
I had been wondering when he was going to do it, but as above, I had other things on my mind.
Whilst having coffee this morning with my 97 year old Mother-in-Law, I noticed on her window-cill, a blanking plate.
I deemed it better to quietly remove it, rather than set up a "Why is it there.." situation, she has dementia and probably some other age related condition(s) too.
Plugged it and "Hey-Presto" all's well with DC.... 

I've phoned the owner, apologised for the delay, and told him he can collect.
Many thanks again for you guidance.
IF it had been my loco, and because I'm a DC dinosaur, I would have stripped all the gubbins off and wired the pick-ups directly to the motor   

Luckily you spotted the blanking plate. Saved a lot of trouble.

[34theletterbetweenB&D]

22 hours ago, Penlan said:

...Whilst having coffee this morning with my 97 year old Mother-in-Law, I noticed on her window-cill, a blanking plate.
I deemed it better to quietly remove it, rather than set up a "Why is it there.." situation, she has dementia and probably some other age related condition(s) too...

Tangential, but this is very familiar. With my MiL, 'events' included most of her husband's socks neatly paired and carefully laid in a freezer drawer, and the several discoveries of an entire year's worth of family birthday cards already signed, sealed, stamped, but not posted, 'stashed away' in safe locations. Best just sorted out without any mention...