# How do I disassemble a 50175 Speed Controller



## Grant_1966 (Dec 14, 2018)

Hello Everyone, I have an LGB 50175 Speed Controller. There’s 19VAC from the Transformer but only 8 DC to the trackside contacts. I’d like to open it up to clean the contacts and inspect it but I’m not sure how to do that without damaging the tabs in the four slots on the base.

The unit is a little red box with four recesses in the bottom. It appears there are tabs within the recesses but no matter how I manipulate the tabs, I can't get them to release.


Looking to the vast experience of the group to help this noobie! Grant


----------



## fredlub (Feb 7, 2010)

From experience: The LGB controllers are not made to be opened.
Regards
Fred


----------



## Treeman (Jan 6, 2008)

They must have thought that they would never need repair.


----------



## LGB333$$$$ (Oct 11, 2017)

Grant_1966 said:


> Hello Everyone, I have an LGB 50175 Speed Controller. There’s 19VAC from the Transformer but only 8 DC to the trackside contacts. I’d like to open it up to clean the contacts and inspect it but I’m not sure how to do that without damaging the tabs in the four slots on the base.
> 
> The unit is a little red box with four recesses in the bottom. It appears there are tabs within the recesses but no matter how I manipulate the tabs, I can't get them to release.
> 
> ...


It appears your LGB 50175 controller (very basic model) is defective so you should consider buying a replacement LGB controller. But you indicated you're getting 19 VAC from the transformer........you need DC volts to the controller, not AC. What power supply are you using........the LGB 50175 needs DC input. If you are getting proper DC current to the controller, then it's defective. There are various LGB used (or new) controllers available for a reasonable price. For example, I recently bought a used LGB 5007 (DC input only) from PizzaTrains.com for $30. OnlyTrains.com also has used items for sale, and of course, there's always eBay.com and eBay.de (Germany). To reiterate, most LGB controllers must only be connected to a DC output power supply such as LGB 5006 2 amp DC power supply. The newer LGB controllers, LGB 51070 or 51079, can be used with either DC or AC output power supplies.......they can convert AC input to DC output to your track.


----------



## Dan Pierce (Jan 2, 2008)

For a great DC source, I use laptop power supplies. Dell has 19+ volts at over 4 amps and these are often discarded when the laptop fails. LGB 2 amp controllers work real well with these.
Remember that the 4 foot diameter curves do not need the full 24 volts as engines will 'fly' off the track at full speed. Also these are great on a test bench.


----------



## LGB333$$$$ (Oct 11, 2017)

Dan Pierce said:


> For a great DC source, I use laptop power supplies. Dell has 19+ volts at over 4 amps and these are often discarded when the laptop fails. LGB 2 amp controllers work real well with these.
> Remember that the 4 foot diameter curves do not need the full 24 volts as engines will 'fly' off the track at full speed. Also these are great on a test bench.


Dan - Wow........never thought of using a laptop power supply for the large scale model trains hobby. Thanks for the idea!


----------



## du-bousquetaire (Feb 14, 2011)

I had the same problem on my large Fleishman transformer which I use for testing in the workshop. Both I understand are the same design made by Buhler and only the colour of the plastic case changes. I also had developped some bad contact problems and wanted to open it I finally asked a friend who does repairs in a big Paris hoby shop , He explained to me that you have to push in those plastic 4 tabs Which does seem a brutish type of way to do it but it works. It turns out all I needed to do was to gently push up the circular copper contact shets for the cursor, this reestablished the intermitent contact and it is like new again. It went back together again after the operation.


----------



## Totalwrecker (Feb 26, 2009)

LGB333$$$$ said:


> Dan - Wow........never thought of using a laptop power supply for the large scale model trains hobby. Thanks for the idea!







A source for similar devices; http://www.mpja.com/Switching-Linear-Power-Supplies/departments/547/


----------



## Jerry S (Dec 31, 2021)

LGB333$$$$ said:


> It appears your LGB 50175 controller (very basic model) is defective so you should consider buying a replacement LGB controller. But you indicated you're getting 19 VAC from the transformer........you need DC volts to the controller, not AC. What power supply are you using........the LGB 50175 needs DC input. If you are getting proper DC current to the controller, then it's defective. There are various LGB used (or new) controllers available for a reasonable price. For example, I recently bought a used LGB 5007 (DC input only) from PizzaTrains.com for $30. OnlyTrains.com also has used items for sale, and of course, there's always eBay.com and eBay.de (Germany). To reiterate, most LGB controllers must only be connected to a DC output power supply such as LGB 5006 2 amp DC power supply. The newer LGB controllers, LGB 51070 or 51079, can be used with either DC or AC output power supplies.......they can convert AC input to DC output to your track.


----------



## Jerry S (Dec 31, 2021)

The output from the power supply is AC DC. The controller 50175 converts the AC to DC which is connected to the track. So if you are getting 19VAC then the controller is defective. It is a combination rectifier snd speed controller.


----------



## Jerry S (Dec 31, 2021)

Jerry S said:


> The output from the power supply is AC not DC. The controller 50175 converts the AC to DC which is connected to the track. So if you are getting 19VAC then the controller is defective. It is a combination rectifier and speed controller.


----------



## Greg Elmassian (Jan 3, 2008)

Jerry, you are responding to a 3 year old thread, doubtful if the issue still exists.

Also, you seem to be just doing a reply with no content, or you quoted your own post.

Slow down, and maybe introduce yourself in the new member forum and tell us a bit about yourself first, and what plans you have.


Greg


----------



## Dan Pierce (Jan 2, 2008)

All of the LGB EPL switch boxes (5075, 50175, 51175) need AC input. If DC is used then you cannot switch the EPL drive in both directions. Also using the 5275 booster is very helpful.


----------



## Greg Elmassian (Jan 3, 2008)

Dan, he was not asking a question, but replying to an old thread.


----------

