Welcome to the forum   
Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Share
Options
View
Go to last post in this topic Go to first unread post in this topic
Offline johnmarklin  
#1 Posted : 24 February 2018 17:23:34(UTC)
johnmarklin

Ireland   
Joined: 31/03/2011(UTC)
Posts: 171
Location: Ireland
Good afternoon fellow Marklin Gauge 1 enthusiasts. I am in need of assistance with a problem I have with my class 78.

When I try to change the direction of travel for the locomotive the locomotive leaps forward at high speed and continues traveling in the same direction and the relay just buzzes when I try to change direction. I have adjusted the relay spring tension but this makes no difference. The relay works perfectly when wired directly without the circuit board. I have replaced the relay with another relay but the problem is still the same.

What is the function of the circuit board and is it possible to get a replacement/repair board anywhere. I have checked the Marklin shop but this part is no longer available.

Your thoughts, observations or recommendations would be appreciated.

John
Offline Markus Schild  
#2 Posted : 24 February 2018 22:25:49(UTC)
Markus Schild

Germany   
Joined: 14/01/2006(UTC)
Posts: 1,802
Location: Wurttemberg
Hi John,

The circuit board should prevent the loco from jumping while switching and switches the lights.

If it's defective I would replace the circuit and the relay with a Uhlenbrock electronic switch #55700. If you find sometimes the original spares, you can build it back.

Regards

Markus
thanks 1 user liked this useful post by Markus Schild
Offline johnmarklin  
#3 Posted : 26 February 2018 12:05:47(UTC)
johnmarklin

Ireland   
Joined: 31/03/2011(UTC)
Posts: 171
Location: Ireland
Markus,

Thank you for your suggestion.

Before purchasing the Uhlenbrock unit I decided to test the circuit board. The circuit board works, (the mounted relay clicks) and the circuit board delivers a pulse of 25.4 volts when I reverse current at the transformer. I have replaced the relay with another relay which works perfectly without the spring but with the spring attached the relay buzzes. With a lot of adjustment I have managed to improve the situation. I have reduced the tension on the the spring as much as is possible and I also stretched the spring. The result is reasonably satisfactory but not entirely to my liking.

Do the electro magnets of a relay become less powerful over time and if so what is the reason for so?

Best wishes,

John
Offline Markus Schild  
#4 Posted : 26 February 2018 12:12:58(UTC)
Markus Schild

Germany   
Joined: 14/01/2006(UTC)
Posts: 1,802
Location: Wurttemberg
Hi John,

The relays don't get weak. I have some which work perfect for 60 years. As usual at old electronics I would suspect the condenser on the board. These get weak with the years. More if only used rarely. If the specification is readable I would replace it first.

Regards

Markus
thanks 1 user liked this useful post by Markus Schild
Offline johnmarklin  
#5 Posted : 26 February 2018 13:23:30(UTC)
johnmarklin

Ireland   
Joined: 31/03/2011(UTC)
Posts: 171
Location: Ireland
Markus,

Thank you for your message and information. The condenser is the one component that I did suspect. I will work on it later and report on progress.

Best wishes,

John
Users browsing this topic
OceanSpiders 2.0
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

| Powered by YAF.NET | YAF.NET © 2003-2024, Yet Another Forum.NET
This page was generated in 0.432 seconds.