Lights on 2EPB EMU trailer car not working

[philsandy]

I have asked a question about this loco in the DCC  section, but this is a different problem, which I don't think is DCC specific. 

Bachmann 2EPB Class 416:  the interior lights and both the directional headcode lights work on the motor car, but not on the trailer car.

 

The power for the lights to the trailer car comes from the motor car via 2 wires in the coupling/drawbar, one, an orange wire that connects to a terminal on the trailer PCB (PAD2), and a

brown wire that connects to PAD 1. I have tested these pads and there is current to them when the lights are switched on. But there is no current to the terminals at the front end of the cab, (red arrows on 1st photo) that connect to the PCB in the roof for the interior lights.   

Also whilst testing I found that when the probe touched across terminals 1&2 for the headcode lights (see 2nd photo), the lower headcode light came on, when direction was reversed and the probe touched across terminals 2&3 the upper headcode light came on.  (This photo is actually of the motor car, but both cars headcode PCB's  are the same).

Can any one offer any advice?   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited December 14, 2019 by philsandy
typo

[RFS]

The lights are organized on the basis that they are directional even though they only show white lights. Hence the two lights in the head code, and you can clearly see when you change direction that all the lights blink. My view is that the head code PCB is not the problem as the interior lights don't work either. The circuitry involves the two feeds with return being via the rails. On the class 411 4-CEP, the interior lights and head codes work independently via F0 and F1: the 2-EPB was supposed to be the same but something went wrong in production! So on the 2-EPB the interior lights and head code are one circuit. On the Kernow Thumper the head codes do switch between red and white, but the interior lights are controlled by a physical switch underneath.

 

My first suggestion would be to look at the conductive coupling to make sure it's not damaged, or possibly fixed the wrong way up. It's all too easily done. Another place to investigate is under the floor on the inner ends of both coaches to make sure the wires there have not become detached. 

[philsandy]

6 hours ago, RFS said:

The lights are organized on the basis that they are directional even though they only show white lights. Hence the two lights in the head code, and you can clearly see when you change direction that all the lights blink. My view is that the head code PCB is not the problem as the interior lights don't work either. The circuitry involves the two feeds with return being via the rails. On the class 411 4-CEP, the interior lights and head codes work independently via F0 and F1: the 2-EPB was supposed to be the same but something went wrong in production! So on the 2-EPB the interior lights and head code are one circuit. On the Kernow Thumper the head codes do switch between red and white, but the interior lights are controlled by a physical switch underneath.

 

My first suggestion would be to look at the conductive coupling to make sure it's not damaged, or possibly fixed the wrong way up. It's all too easily done. Another place to investigate is under the floor on the inner ends of both coaches to make sure the wires there have not become detached. 

 

Thanks for your reply RFS, which led me to where problem was. The loco has been converted to EM and the copper wheel bearings removed to facilitate the wider gauge, (it's a tight fit between the frames), the trailer car wheels were not picking up from the rails, so the circuit had no return. 

 

If I fitted pickups to just one bogie (ie. so 4 wheels would be picking up) would that be enough for the lights to work, or would both bogies need doing?

Edited December 14, 2019 by philsandy
add

[SRman]

11 hours ago, philsandy said:

 

Thanks for your reply RFS, which led me to where problem was. The loco has been converted to EM and the copper wheel bearings removed to facilitate the wider gauge, (it's a tight fit between the frames), the trailer car wheels were not picking up from the rails, so the circuit had no return. 

 

If I fitted pickups to just one bogie (ie. so 4 wheels would be picking up) would that be enough for the lights to work, or would both bogies need doing?

Pickups on one bogie would work, but on both bogies would be better for less flickering.

[RFS]

10 hours ago, SRman said:

Pickups on one bogie would work, but on both bogies would be better for less flickering.

 

I would endorse that. I'm not sure how the circuitry works though. On mine, if I tilt the trailer coach so that only the wheels on side are in contact with the rails, the lights stay on but dim slightly. Same happens whichever way I tilt the coach. Nevertheless these units are very prone to flickering, with one main cause being the conductive coupling. 

[philsandy]

I fitted pick ups to both bogies and the all the lights work when loco is in FWD direction, when I reverse the loco direction the interior lights in the trailer car go off and there is no head code light. I swapped the connections on the trailer PCB, orange wire to PAD 1, brown wire to PAD 2, but still got the same result.

Can any one suggest the cause?

[RFS]

The trailer bogies pick up from both bogie sides with each feed going to a separate connection on the internal PCB. That's why there are two head code lights - one for each direction. Sounds like you are only picking up from one side?

[Philip D]

Lights on mine flickered from new out of the box. Returned to Bachmann, and it came back a bit better but still not great. Since then I've cleaned all the contacts and the power car is OK but the trailer still flickers. I suspect the roof contact - press gently on the centre of the roof and the lights are steady. Maybe a touch of copper grease next, to try and improve the contact?

[dhjgreen]

15 minutes ago, Philip D said:

Lights on mine flickered from new out of the box. Returned to Bachmann, and it came back a bit better but still not great. Since then I've cleaned all the contacts and the power car is OK but the trailer still flickers. I suspect the roof contact - press gently on the centre of the roof and the lights are steady. Maybe a touch of copper grease next, to try and improve the contact?

The roof is a separate part so you might not be affecting the long contact for the lights.  Did you clean the wheel point contacts?

[RFS]

1 hour ago, Philip D said:

Lights on mine flickered from new out of the box. Returned to Bachmann, and it came back a bit better but still not great. Since then I've cleaned all the contacts and the power car is OK but the trailer still flickers. I suspect the roof contact - press gently on the centre of the roof and the lights are steady. Maybe a touch of copper grease next, to try and improve the contact?

 

The roof contacts are sprung copper strips which press onto contacts attached to an upright pillar. This allows the body to be removed without having to disconnect any wires. Making the lights work by pressing down on the roof may indicate an issue with these contacts and it might be worth taking the body off and checking. However, pressing down on the coach may also be causing the wheels and their pickups to be making better contact and that's where the problem might lie. 

[dhjgreen]

33 minutes ago, RFS said:

 

The roof contacts are sprung copper strips which press onto contacts attached to an upright pillar. This allows the body to be removed without having to disconnect any wires. Making the lights work by pressing down on the roof may indicate an issue with these contacts and it might be worth taking the body off and checking. However, pressing down on the coach may also be causing the wheels and their pickups to be making better contact and that's where the problem might lie. 

I didn't make myself very clear earlier, the roof you see is a false one and can be removed, the top of the carriage is a moulding with the sides and ends.  With the shape of the inner roof I think it unlikely you can easily deflect it by pressing the false roof with your fingers.

Edited January 4, 2020 by dhjgreen

[Philip D]

Thanks for the thoughts. I'll have another go at the wheel contacts first and see if that helps

[RFS]

4 hours ago, dhjgreen said:

The roof is a separate part so you might not be affecting the long contact for the lights.  Did you clean the wheel point contacts?

 

2 hours ago, dhjgreen said:

I didn't make myself very clear earlier, the roof you see is a false one and can be removed, the top of the carriage is a moulding with the sides and ends.  With the shape of the inner roof I think it unlikely you can easily deflect it by pressing the false roof with your fingers.

 

The roof is not a separate part. The roof, sides and ends form a single moulding with the PCB containing the LEDs being fixed to the underside of the roof. I have 5 of these 2-EPBs myself and have taken the body off them several times, not least to fit DCC decoders to the power cars. The electrical connection to the PCB in both coaches is via two copper strips which press onto vertical contacts on the carriage floor. If these are not making good contact you may have to bend them slightly to improve it. Pressing on the roof may be just enough to do that, but it's more likely the problem lies in the pick-up area, or with the conductive coupling. 

[dhjgreen]

16 hours ago, RFS said:

 

 

The roof is not a separate part.....

 

[RFS]

OK - I stand corrected! You've obviously gone a lot further than I have in disassembling this unit and I've always thought the body was a single moulding as with some other Bachmann coaches. I've disassembled the motor coach chassis to sort out problems with the motor, but not the body. 

 

So pressing down on the roof may not have any effect if the problem with the lights is poor electrical contact between the copper strips in the PCB and the contacts on the chassis body. It's still worth checking though as I had a motor coach where the lights were flickering but not the head-code lights. I have at present a unit where the trailer lights are more often off then on: pushing the trailer closer to the motor coach fixes it, so I suspect it's the connections between the conductive coupling and either the trailer or motor coach. 

 

Just hope the forthcoming 2-HAP, whenever it arrives, has the same solution as the 4-TC whereby there's a 4-pin connection between the coaches. On the 4-TC it means all 16 axles act as full pickups for both decoder power and lighting, and flicker is totally absent.