LGB 51750 with two switch connections not working

N

nlevasseur

Registered
Country flag
Normally, I can find answers by searching the previous posts but not this time… Newish to this forum, and have been doing more with G scale LGB more recently. So I picked up a 51750 off eBay and when I hooked it up to test it with a signal switch motor, two of the rockers worked great while the other two were non functional.

I searched all previous posts on the forum and found nothing similar as to some faulty rocker switches. I have not metered anything.

The 51750 is hooked up to the ac terminals on a LGB transformer with short leads.

Functional meaning they would actuate the 5094 signal switch motor in both directions.

Non-Functional meaning they would not actuate the 5094 signal switch motor in any direction.

I used the same 5094 for testing each of the 4 rocker switches just moving the leads to the white and orange terminals for each rocker switch.

I took the bottom of the 51750 off, but there is no way to get at the other side of the circuit board and rocker switches.

Any ideas? Does it sound like the diodes on two of the rockers have gone bad? Any way to get at the other side of the circuit boards and rocker switches?

I have other 51750 that work just fine.. Thanks for weighing in.
 
nlevasseur said:
Normally, I can find answers by searching the previous posts but not this time… Newish to this forum, and have been doing more with G scale LGB more recently. So I picked up a 51750 off eBay and when I hooked it up to test it with a signal switch motor, two of the rockers worked great while the other two were non functional.

I searched all previous posts on the forum and found nothing similar as to some faulty rocker switches. I have not metered anything.

The 51750 is hooked up to the ac terminals on a LGB transformer with short leads.

Functional meaning they would actuate the 5094 signal switch motor in both directions.

Non-Functional meaning they would not actuate the 5094 signal switch motor in any direction.

I used the same 5094 for testing each of the 4 rocker switches just moving the leads to the white and orange terminals for each rocker switch.

I took the bottom of the 51750 off, but there is no way to get at the other side of the circuit board and rocker switches.

Any ideas? Does it sound like the diodes on two of the rockers have gone bad? Any way to get at the other side of the circuit boards and rocker switches?

I have other 51750 that work just fine.. Thanks for weighing in.
Click to expand...
viaEstrecha viaEstrecha had a problem with one of his, I have 2 that have 1 faulty switch. General feeling is that they are pretty well impossible to recondition. But Martyn will likely pip in, link you to his posts.
 
The bulk of my railway was obtained second hand but whilst most items can be coaxed back to life, the LGB51750 beat me, as to take it apart, you have to desolder the rocker switches and then somehow get the circuit board out, both of which seem guaranteed to destroy the innards.
IMG_4641 (Medium).JPEG
For me, the only solution was to completely wreck the original, as 3 out of 4 switches (or their diodes) had failed, and I put in a false panel with 4 DPDT momentary toggle switches with a chunky capacitor. I recycled half of the old circuit board to retain the external connections and replaced the green LED and also added a jack socket for the supply.
IMG_4653 (Medium).JPEG
The inelegant bodge does operate 4 EPL drives from the same AC supply, so it functions as before. Disappointing not to be able to repair, but making the best of a bad job.
IMG_4655 (Medium).JPEG
 
From (failing) memory I think I recall a member who had some success with contact cleaner squirted past the rocker switches then blasted out with compressed air.

I've searched but can't find the post in question.EDIT: Found it at:

T

Post in thread 'LGB 5075'

I realize this is an old thread, but I wanted to post a reply as it came up in many repeated searches as I was trying to figure out how to fix a couple of "dead" switches on two "new to me" 5075 switch boxes and I figured that my solve might help someone else. I was trying to take my boxes apart to see if I could figure out what was wrong and came to the same conclusion that without some special tool setup some form of destruction was necessary to open them.

However, I ended up trying something else much simpler that worked in my particular case. A can of aerosol "sensitive electronics...
  • Like

On several occasions I have suspected dirty contacts to be the problem when a longer, firmer press on the switch causes it to function. Sort of no-so-momentary contact.
 
Last edited:
OBBherr said:
From (failing) memory I think I recall a member who had some success with contact cleaner squirted past the rocker switches then blasted out with compressed air.

I've searched but can't find the post in question.EDIT: Found it at:

T

Post in thread 'LGB 5075'

I realize this is an old thread, but I wanted to post a reply as it came up in many repeated searches as I was trying to figure out how to fix a couple of "dead" switches on two "new to me" 5075 switch boxes and I figured that my solve might help someone else. I was trying to take my boxes apart to see if I could figure out what was wrong and came to the same conclusion that without some special tool setup some form of destruction was necessary to open them.

However, I ended up trying something else much simpler that worked in my particular case. A can of aerosol "sensitive electronics...
  • Like

On several occasions I have suspected dirty contacts to be the problem when a longer, firmer press on the switch causes it to function. Sort of no-so-momentary contact.
Click to expand...
Thank you
 
OBBherr said:
From (failing) memory I think I recall a member who had some success with contact cleaner squirted past the rocker switches then blasted out with compressed air.

I've searched but can't find the post in question.EDIT: Found it at:

T

Post in thread 'LGB 5075'

I realize this is an old thread, but I wanted to post a reply as it came up in many repeated searches as I was trying to figure out how to fix a couple of "dead" switches on two "new to me" 5075 switch boxes and I figured that my solve might help someone else. I was trying to take my boxes apart to see if I could figure out what was wrong and came to the same conclusion that without some special tool setup some form of destruction was necessary to open them.

However, I ended up trying something else much simpler that worked in my particular case. A can of aerosol "sensitive electronics...
  • Like

On several occasions I have suspected dirty contacts to be the problem when a longer, firmer press on the switch causes it to function. Sort of no-so-momentary contact.
Click to expand...
Thank you
 
I made my own switch panel and I have 8 switches controlled via a single smaller box. And I only used 2 diodes. I used the single pole double throw momentary switch and just ran a wire from he same side of all switches to one diode and on the other side of the switch to the other reversed diode. Then the middle contact to each individual LGB switch. the second LGB switch wire went directly to the power source as well as the 2 diodes. Ben working great for 15 years.
 
Dan said:
I made my own switch panel and I have 8 switches controlled via a single smaller box. And I only used 2 diodes. I used the single pole double throw momentary switch and just ran a wire from he same side of all switches to one diode and on the other side of the switch to the other reversed diode. Then the middle contact to each individual LGB switch. the second LGB switch wire went directly to the power source as well as the 2 diodes. Ben working great for 15 years.
Click to expand...
Thanks so much for your reply. Can I ask what size diodes did you use? Thanks again.
 
viaEstrecha said:
The bulk of my railway was obtained second hand but whilst most items can be coaxed back to life, the LGB51750 beat me, as to take it apart, you have to desolder the rocker switches and then somehow get the circuit board out, both of which seem guaranteed to destroy the innards.
View attachment 333856
For me, the only solution was to completely wreck the original, as 3 out of 4 switches (or their diodes) had failed, and I put in a false panel with 4 DPDT momentary toggle switches with a chunky capacitor. I recycled half of the old circuit board to retain the external connections and replaced the green LED and also added a jack socket for the supply.
View attachment 333857
The inelegant bodge does operate 4 EPL drives from the same AC supply, so it functions as before. Disappointing not to be able to repair, but making the best of a bad job.
View attachment 333858
Click to expand...
Well I figured out how to disassemble it, but paused after reading another post about contact cleaner. It’s easy to take the bottom off with a small blade screw driver to pry the side away from the black tabe on each end of hate base. Then I unscrewed the female power connections on the left side and did the same with the male pin on the right side. Once those are removed, the back row connections for switches easily flexes and thanks to your post, I realized I’d have to unsolder each switches 6 connections … then I read the post about contact cleaner so I bought a can of CRC QD Contact Cleaner. Using the pin point tiny “straw“ I sprayed around the black rocker of the two switches that didnt work, then used a compressed Air can to blow out the excess. 1 of the two faulty switches works great now and the other works in one direction which means I have to try the cleaner again. Thanks everyone for the assistance! Much appreciated.
 
You must log in or register to reply here.
Back
Top Bottom