The Randall Museum in San Francisco hosts a large HO-scale model model railroad. Created by the Golden Gate Model Railroad Club starting in 1961, the layout was donated to the Museum in 2015. Since then I have started automatizing trains running on the layout. I am also the model railroad maintainer. This blog describes various updates on the Randall project and I maintain a separate blog for all my electronics not directly related to Randall.
2024-08-07 - What’s in a Tortoise ?
Category RandallThe turnout T324 on the branchline has multiple issues.
One of them is that clearly the contacts on the Circuitron Tortoise Slow-Motion Switch Machine do not work as expected.
So what’s inside a Tortoise?
It turns out that it’s quite easy to open once you figure that the screws are “hidden” under the label. No need to force the plastic as I unfortunately started doing first.
I guess the warranty is void now… What warranty anyway? That switch machine is likely 10 years old or more -- every single Tortoise on the Randall Model Train Railroad was installed by the GGMRC members and thus that had to be before 2015. According to the “recent changes” on the Tortoise page, the tan color of the circuit board indicates a unit built before 2019.
The auxiliary contacts are simply printed on a small motherboard on the side:
Originally I wrote this off entirely, but now that I see that, I’m thinking a bit of CRC-226 on these contacts is probably all it needs to restore it to pristine condition.