I’m attempting to resurrect parts of a layout I had built some thirty years ago.
I am trying to make work a transistor throttle I built from plans I think were
published in Model Railroader. Of course, I can’t find the plans.
Anyone remember the article and perchance have a copy of it?
This was published before the CTC-16 articles.
I’ve found some broken wires and I don’t know where they go.
Any help would be appreciated.
Thanks.
Alan
There were many articles published with throttle designs in that era. Without a complete index it would be hard to track the several or more SCR designs, and then bounce them against you to see if they struck a memory chord.
Best bet would be to search the Internet for SCR throttles. Look at several circuits, and see if a couple don’t come close to your throttle, enough to tell where the broken wires go. Or build a new throttle using your existing components and a present-day circuit as a guide.
my thoughts, your choices
Fred W
Many of the DC ‘Super Throttles’ from 20-30 years ago hardly work now. If this is an SCR one, you might have a chance finding replacement parts. The old TAT series with transistors, finding a match for leaky transistors is real tough. I suspect this is going to be one of those projects one does just to see if you can get it to work.
I had a pair of the TAT series throttles I built in the late 60’s from the MR articles. They worked fine. By the time I built a new permanent layout in 1887, they did not have very much power. Leaky diodes/transistors were the problem. I fixed one, but then bought MRC CM20 walk-arounds on sale. I never bothered to repair the other unit. I took them to several model train flea markets, got a lot of interested looks, but no offers. They went in the trash. There are a lot of good DC throttles out there. Good luck with your ‘retro’ project.
Jim
I remember the article and I will look thought my old back issues as I do remember trying out the circuit many years ago.
Rich
I think the SCR throttle might have been by Thorne in the 1970’s as I have some articles by him but not the SCR one.
Hansen did some throttle stuff in the 1980’s, Symposium on electronics but I did not find the SCR by him.
One person did the TAT 5 but not SCR.
While looking, I had a fantasy idea. Maybe Kalmbach could develop an on line search-able model railroad index. This would help the model railroad community immensely.
Do you have a photo or a little more detaill on what you have?
Rich
From a google search: I think the article is in this book.
Model Railroad Electronics: Basic Concepts to Advanced Projectsn by Peter Thorne
ISBN 0890241465
I did find out the article is in the June 1977 MR. Also, it seems as the device was a MOSFET, not a SCR but still looikg.
Rich
There was an SCR throttle in Thorne’s “Practical Electronic Projects for Model Railroaders” but good luck getting a copy of that, it’s long out of print. There’s a bit more complex one here: http://home.cogeco.ca/~rpaisley4/SCRCircuits.html
The principle is the same for all of them, with a little patience it should eb not too difficult to see where the missign wire goes. Or the completely unelectronic method - if a previously sodlered on wire broke off, there will still be a little stub of the wire sodlered to whereever it broke off - use a magnifier to look at all joints and terminals and I;ll bet you can spot where it goes.
–Randy
Rich,
Thanks for looking.
I had back issues of MR from the late 70’s through the late 80’s.
I gave them all to a friend when I left my last house around '89.
I do have Practical Electronic Projects for Model Railroaders by Thorne. And there is a transistor
throttle in it, but, it isn’t the one I built. This one uses a printed circuit board, way too advanced for
me at the time. Mine was built on what I think was called “perf” board. And it definitely used an SCR.
It also was capable of walk-around tethered hand held controllers.
I really don’t have the room to build the layout I had dreamed, so, just looking for a little book shelf kind of thing with some suoer detailed dioramas.
I appreciate any help I can get with this.
Thanks.
Alan
Someone will prbably have the article but below is a link to the magazine. I have bought from him.
http://www.railroadtreasures.com/Railroad%20Books/Railroad%20Books%20the%20entire%20list.htm
Search Amazon.com for Practical Electronic Projects for Model Railroaders
Rich
Hi Alan
I will continue to look. If I can get down to our model railroad club, I am pretty sure the issues is there. Just don’t know when. I do remember the perf board though. I had used perf board but never did get the throttle to work like I wanted it to.
Rich
It’s probably almoist the same circuit as Thorne’s though. My copy is marked p where I planned to build that - no way I would have etched a pc board either, it would have been point to point wired on a perfboard. Thorne just tookt he opportunity since it was a fairly simple circuit to show how you could buy the kit from Radio Shack and make your own board. I did build the more advanced CD power supply from the book, and I had most of the parts but never built the fancier transisotr throttle - the one with the multiple brake rates and pulse adjust stuff. Actually according to my scribblings in the book I altered it to use the more simple pulse injection from one of the other throttles, and also eliminate the diesel horn portion. I think about that time I aquired a Tech II 1500 and didn’t need to roll my own throttle.
–Randy
Randy,
with a little patience it should eb not too difficult to see where the missign wire goes.
Yup! I looked more carefully last night and found where the wire goes.
Yeah! It works!
Still, I’d like to review the original plans.
Thanks.
Alan