Troublesome Point
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Nigel
©Nigel C. Phillips
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From a discussion in Model Railway Hobbyist (Tortoise switch machine connectors - the MRH Forum March 2020):
"Be careful which connectors you purchase. Due to supplier issues last year Circuitron did a minor redesign of Tortoises, so you also need to be aware of what version(s) of Tortoises you have on hand. The older Circuitron Tortoise reference specified 0.156†(3.96 mm) center to center contact spacing, where the Changes Coming note on the Tortoise page (see quote below) indicates a contact spacing of 3.81 mm (0.150"). This is not a lot, but it is enough to allow for misalignment of the contacts (which has always been an issue). Circuitron also changed the width of the PCB edge connector which will now allow the use of Molex or Molex compatible eight pin edge connectors and which avoids the misalignment problem." Ken K. 2020
"Because of the width of the connector section of the OLD Tortoise PCBs, Circuitron recomended using 10 pin connectors to cover the 8 pins and making no connections to the outer pins. The housing of standard 8 pin Molex connectors are too narrow to fit over this section of the OLD Tortoises, and the connector spacing is different. You could always do what some did and cut or file down the edges of the PCBs.: Ken K again.
From the Circuitron web site:
The new circuit boards will be made of FR-4 epoxy laminate and will be GREEN on both sides. This will provide easy identification of the newer boards, but other than appearance and quality, the new boards are very similar to the ones we have been using for 34 years. Except for a couple things. The new boards have a wider, industry standard connection flange whereas the older tan boards were undersized. This may create problems if you are trying to fit a new TORTOISEâ„¢ into an older undersized edge connector. But they will fit fine in any industry standard 8 position edge connector. In addition, we took the opportunity to change the hole spacing and added a new row of holes as well. This will allow the use of Molex style connectors as well as the 3.81mm spaced terminal blocks that CIRCUITRON already sells and uses on our SMAILâ„¢.
Many modelers just simply hard wire them and avoid all of this.
Nigel
©Nigel C. Phillips
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Hi Peter
Delighted you got it sorted :thumbs
"Edge Connectors" that was a bit of a last minute revelation…….worthy of Agatha
Best Wishes
John
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I knew the edge connectors could cause problems although I've never experienced it myself and yes John, I only mentioned the edge connectors to keep you all guessing right up to the punch-line !! I'm sure, under the same circumstances, Agatha would have done the same ……………………..
Maybe I had used a pre-change connector with a post-change motor - no idea.
It does highlight the advantages, or otherwise, of stay-alives. It was only when I ran non-fitted short wheelbase locos over that point that the problem came to light. The "fitted" ones didn't bat an eyelid. I initially assumed it was dirty track or wheels causing the problem - I'm not too hot on permanant way maintenance, particularly in this "testing" stage !!
As this area will eventually be hidden under the top deck I decided now was the time to make sure everything worked perfectly before doing any further construction.
I'm gradually working my way around the layout ironing out any snags which, given the Covid induced shortage of some necessary replacements, is taking much longer than it ought.
Maybe I should learn a bit more about the trickery Martin mentioned although to my little brain, "relay" still means passing a rolled up newspaper tube on to the next runner …………………………….
I thank you all for your thoughts and suggestions - every one of them has taught me a little more.
'Petermac
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