help with directional short on lgb 2036 20th ann trolley

stevedenver

stevedenver

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last time i ran this trolley there were no issues. it was last run, about 3-5 months ago. put into its box. nothing unusual, not dropped. bone dry.

1 problem: runs great one direction, appropriate head and tail light work, in reverse, however, it creates a "short" ie barely any slow movement in other direction, (clearly something is crossed with a trickle of electricity still getting to the motor despite the load of the short) , then trips breaker.

this problem appeared this morning on the track. I tried a few reverses. all still had the above short. But,

2 for a very brief moment, this short went away when i reversed. Trolley traveled maybe an inch. then reappeared. short still there.

3 took off roof, no difference. short still present

4 slid track/catenary switch several times between catenary to track power, no difference.short still present. disassembled chassis frame section that holds block to body.

5 examined printed tracer board (under passenger seating area) which directs track /catenary power and which g-y-w lead connects to motor block as well as being connected to this board and which supplies power to the brass roof contacts. no visibly apparent connections between circuit printing , solder point, and wire feeds. ran a screw driver between printed sections which are close just incase, no change.

6 removed motor from block, motor works great both directions.. reinserted motor into block and then attached power clips to appropriate motor block pins (old three pin style, no problems, no short in both directions.

7 with roof still detached, BUT now with car wiring harness attached to block, I still have uni directional short. so, its in the car lighting circuit i guess. More specifically in the head light, tail light or under passenger feeder board.

8 i removed the body platform ends, in which head lights and led tail lights are housed, red tail light LED boards are housed, they are connected to the small marklin inter car lighting circuit plugs. I examined each board for any connection between soldering and wires etc. nothing i can see. No discoloration of a fried component (but i didnt allow the short to persist long at all). again ran a screw driver between the very close printed tracer sections just to make sure these was no connection.

9 removed headlight 24v screw bulbs to eliminate bulb issue. no change. still have short. Examined bulb bases, all appears fine, no frayed wires, base contact and threads all clean.

10 gently moved/wiggled the LED circuit wires which are soldered to the mini board with the diodes. I tried this just in case there was a stray wire strand, bare portion of insulation etc. still have short.

the trolley is clean, no corrosion, no dirt, basically almost like new. upon disassmebly, very little in the way of dust, grit, etc.

i dont know what to do. i suspect a diode failure, but i am ignorant of this stuff and how to check. it is very likely i am wrong about the diodes, its just a guess.

help please.
 
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LGB 2036
thanks greg
i just assume everyones a red boxer.......LOL
 
Did you try powering the motor block alone from the wheels/skates in both directions? I think you need to jumper the brown and green motor block pins to do this. From what you've already checked its unlikely the problem is in the motor block but just being through.
 
By the time your testing got to point 6,in the first post, you have proved motor and block are OK..

Three-connection block, and '24V bulbs' so we can assume that you are running analogue, and the circuitry will be very simple. - This is not a dig at you, just my thought-processes.

Quite often, on models of this style, there is a small piece of circuit board with two diodes. I am thinking one of these has failed?

Can you run with the lights disconnected? - It may not be possible to do this.
Can you post pictures of the wiring / boards?

PhilP
 
PhilP said:
By the time your testing got to point 6,in the first post, you have proved motor and block are OK..

Three-connection block, and '24V bulbs' so we can assume that you are running analogue, and the circuitry will be very simple. - This is not a dig at you, just my thought-processes.

Quite often, on models of this style, there is a small piece of circuit board with two diodes. I am thinking one of these has failed?

Can you run with the lights disconnected? - It may not be possible to do this.
Can you post pictures of the wiring / boards?

PhilP
Click to expand...
I would focus on the screw-in bulb socket which incorporates close tolerances that are virtually invisible. Check for a short at its base. I note that I experienced two such failures albeit with trolleys from another manufacturer. The p.c. mount complicates repair/replacement.
 
Thanks
ill try disconnecting the diode board as that what i suspect too, a diode problem. These are soldered on , so ill try disconnecting on at a time and test to see if short disappears. Then pull on diode at a time from the board and jumper the connection holes.

this is the only way i can run without lights. ie unsolder both boards. I strongly suspect this would fix the problem.

i have never has a short resulting from an lgb screw in or other light socket. At worst, bulbs come lose and need to be tightened.

Seems unlikely that a “mechanical” issue in a heavy brass socket would suddenly appear in storage as opposed to a diode /component failure.

i have had other electrical components in old lgb boards (flasher on mow , speed control on snow plow) i guess it was either qc, or simple age.
 
Unless you create a problem, like a short-circuit, electronic components tend to fail at (or soon after) turn-on..

I think you will be able to identify the power from the motor-block to the little lighting board..
Lifting either of these input wires, will isolate the lights.

PhilP
 
Yeah
thinking out loud here ree mini board

its a diode linked to a resistor for the led,
the diode controls the directional lighting of the headlights, and is also connected to the led resistor.

and the sudden failure fits..
time was up, i guess.

now to find the culprit..upon more thought, it has to be a diode.
this would explain the short if the the didoe on one end now bleeds current in both polarities.
if it was a resistor, the led would have simply burnt out
 
I think I would be tempted to wire the coco motor direct to the pickup to get it working again, as it is an old beastie with no DCC all you would likely loose are the lights. Is this so important?
 
Actually light are really important to me, a bit of added ‘animation ‘, like smoke and sound.
i have yet to get back to the bench, bit of a late spring storm, garden clean up….

but, i have the option of disconnecting the board(s), replacing the diodoe and or resistor, or
as aboveand replace with leds, possibly color changing, if i can find these in 5mm, if not, separate directional red and white. I can read the bands on the resistor, one gold, three reds.
the diode if this tiny seemingly glass thing.

at this point, since its broken (in one direction) i can feel good about giving it a go.

btw i didnt understand coco.
 
stevedenver said:
Actually light are really important to me, a bit of added ‘animation ‘, like smoke and sound.
i have yet to get back to the bench, bit of a late spring storm, garden clean up….

but, i have the option of disconnecting the board(s), replacing the diodoe and or resistor, or
as aboveand replace with leds, possibly color changing, if i can find these in 5mm, if not, separate directional red and white. I can read the bands on the resistor, one gold, three reds.
the diode if this tiny seemingly glass thing.

at this point, since its broken (in one direction) i can feel good about giving it a go.

btw i didnt understand coco.
Click to expand...
Sorry spelling mistook, meant loco.
 
Im stymied
1
on each lighting board, i pulled out one end of each resistor/diode from the board.
no change in motor problem
2
having then resoldered to original state both of the lighting boards,
i replaced each diode on the board under the passenger seating area, one at a time,. I was careful about using the same exact brand and value of diode (they are identical to the diodes supplied with Lgb 3 way turnouts). Same motor problem, ie fine one direction super slow the other before tripping the breaker.
3 summary, for each resistor and diode, i have taken them out of the circuit, and cannot figure out what causing the short. I am assuming since everything was fine, then the sudden change, some component has failed. In all soldering, i was careful that the joint was solid, and no overage causing an inadvertant connection.
 
If you disconnect the lights, does the motor run in both directions?

PhilP
 
If i disconnect the motor block from the wiring harness to the trolley body, and jumper the w and b pins yes.
its somewhere in the boards.

it is not possible to disconnect the lighting boards without unsoldering. I did unsolder each lighting board, one at a time, and the short remained each time, and, when both lighting boards were entirely unsoldered and removed from the circuit. Short remained.

as such, i concluded that the short must be in a diode in the large board, with the printed tracers for track or catenary function. This board is under the passenger section .On this board the only components are 2 diodes, and a manual pivot switch to change between track and cat.

. I replaced each diode ,one at a time , with a new diode of identical make and value. Each was properly oriented as per the old diodes on the board.
short remained.
 
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stevedenver said:
If i disconnect the motor block from the wiring harness to the trolley body, and jumper the w and y pins yes.
its somewhere in the boards.

it is not possible to disconnect the lighting boards without unsoldering. I did unsolder each lighting board, one at a time, and the short remained each time, and, when both lighting boards were entirely unsoldered and removed from the circuit. Short remained.

as such, i concluded that the short must be in a diode in the large board, with the printed tracers for track or catenary function. This board is under the passenger section .On this board the only components are 2 diodes, and a manual pivot switch to change between track and cat.

. I replaced each diode ,one at a time , with a new diode of identical make and value. Each was properly oriented as per the old diodes on the board.
short remained.
Click to expand...
Hm sounds like there may be a crossover on the circuit board perhaps somehow a piece of solder has melted and connected two of the bits of remaining copper thus creating the short. As the insulating gaps can be quite small it is easy to cause such a short.
 
Yes as to the switch. Its very simple, a swinging arm, easy to see whats going on, but, ill try a hook up in catenary mode, just to see if theres any change
and,
what doesnt make sense, to me, is the fine one day, wonky the next….
has to be(?) a component failure…just cant find it

and as previously mentioned, i traced each circuit print and solder area to be sure there was no inadvertant contact., gap closures
 
Does this car have the same drive as the pignose railcar?

If so, look to the long spring-strips, which centre the drive..

PhilP
 
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