# HO DC Timer Reverse Board, 2nd thread



## T-Man

Having a little extra time I reviewed The auto reverse circuit and decided it was time to update. Basically I would like to simplify it, by doing a step by step. The circuit diagram is a Rob Paisley design.

First I will build a board and then show how to use a Wall Wart to power it. A voltmeter is required to do that since the output of these devices is not always accurate.

To start you need a board.
A 12v relay, RS 275-0248
a 555 timer IC RS 276-1723
two 470k ohm resistors RS 271-1133
100uf capacitor minimum of 16 volt. I used a 35v. RS 272-1028
8 Pin Socket RS 276-1995
a minimum of two 1N4001 diodes, RS 276-1101 two to a package
More may be needed
For the track, I used two 3 amp diodes RS 276-1141

I used 6 terminal connectors 3 to a module. Not required, if you solder everything in. These are harder to find at a Radio Shack store.
RS 276 -1388 will work, four blocks with two connections, to a package.

Also if there is a problem, I prefer a private post until I am finished. It just makes for easier reading and it should not take long to do. The other thread was very popular but not that readable. Thanks for the cooperation. When I am finished I will open it up for comments.

First, I use a 5 by 7 cm board. I show the socket ,relay and the terminal blocks. Electricians normally wire a box with the load to the left. So what I will do is have the 12 supply to the top with positive at the top. The center will be the transformer feed with positive to the top. and the output to the track will be at the bottom. Since this switches, there really is no positive or negative side.
I will show all this when I make the connections.

The relay has the two pins at the top to operate it with 6 pins down below for the switching.










Link to the third thread on the reverse circuit.


----------



## T-Man

*470k resistors*

Next I installed a pair of 470 k ohm resistors. They start at pins 6 and 8 and tie into pin 7. I stretched them out and ran a wire back to pin 7










The flip side show my short cut. I used a piece of copper wire to connect pins 2 and 6. It goes through the center of the chip area and has a small piece of insulation. Every bit counts. This is a small place so I do not use this technique a lot. It saved me one ugly wire on the other side. The dremel is handy to in keeping the connection clean with no shorts.


----------



## T-Man

*Trigger the relay.*

Next I connected pin 3 the trigger to switch the relay. This is done through the 1N4001 Diode, to the positive side of the coil. I also place a diode across the two terminals for the relay coil. The ground is shown in green( I forgot to add it) It goes from the neg side of the coil to pin 1 the ground.

I stretch the diode from the positive relay post to a jumper that leads to pin 3
Also I connected pin 4 to 8 with a wire jumper. I am just following the diagram.
To install these diodes the silver bar points to the right





















This is my original working model, designated as number 3. Yep two failures before this one.











Currently number 5 is being made here. I made 4 yesterday and am testing it out on the track.


----------



## T-Man

*Relay Connections*











The top doesn't show much. The wire is 18 gage and I had to enlarge the holes with a 1/16th drill.
The blue circles are the feeds from the transformer and the relay switches from up to down. With a cross wiring( the x) The polarity reverses on the track when pin 3 triggers the coil to work.











Almost done, I need a capacitor , the power connections,and the wall wart.


----------



## T-Man

*number 5 is up and running*

Today I installed the 100uf capacitor and made the power connections to the ic 555 timer. Now for some problems. Number 4 didn't work on the first try.I had to do a close inspection and with the voltmeter I found the positive feed to the timer was bad. One soldered joint wasn't connected. This gets me thinking on my first attempt. It may be the same problem. Now, number five had two bad joints. One on the negative feed to the 55 timer and one side of the relay itself. So a bad connection in any of these areas, stops the process.

Pin 1 was connected to negative power supply. Pin 8 was connected to positive power supply.










The blue area was a solder joint problem.


----------



## T-Man

*Power Supply*

I use A Wall Wart or Black box. These recharge phones etc. I look for a 12 or 9 volt output in DC voltage. I prefer 9 to 12v. I cut the plug off and measure the voltage and mark the positive lead.This also ensures that it does work. one time I did buy a dud.

The chip will operate to 13 volts and the relay is rated at 12 volts. The board operates fine with a 9 volt power supply. Somehow I don't know if I can trust the readings of the voltmeter. I get the same reading when it is off.
The chip doesn't burn out and it works. The system is reliable and has been running on my table for months. 

The last thing is the diodes on the track. They must point in the same direction to cut engine power when it passes by.When the current is reversed the engine will go back. If using HO the 1N4001 diode works. With Lionel, I used a larger one.

I am tempted to add diodes to lower the power supply voltage. Each diode will lower it by .7 volts. Three diodes lower it by 2.1 volts. I added three to the number 4 board, but after seeing number 5 run without the extra diodes, I am tempted to remove them since nothing is burning out.

That's it! On with the show! Comments Please?
I will get a short video up.
I am still waiting for parts for the welder board.


----------



## tankist

your wire screw terminals seem to be of proper pitch to use on proto board. i had to glue mine near the edge so not to drill holes. which ones did you use? source/cost?


----------



## T-Man

I got them on ebay, a group of two and three connectors.
Radio Shack has smaller blue ones. These green ones are larger.
I got them from Asia engineer. I am not sure of the exact deal I got but here is one.

Back in May of last year I bought 40 pieces for 10 bucks. It might even of been two years ago. I have had them for a while.


----------



## tankist

5mm, pitch. so its every other hole... hmmm
TY


----------



## T-Man

*The Video Test Results*

http://www.youtube.com/watch?v=oCKUKy-m3tc link

I am trying to embed this SEE help section.

This is the link answer to help.








A short version in focus.


----------



## Boston&Maine




----------



## tjcruiser

T-Man,

What's that light-colored loco running on one of your inner tracks? Couldn't quite make it out in the video. 221?

Cheers,

TJ


----------



## T-Man

It's the HO Sante FE Blue Goose ,AHM Rivarossi, from the 80's. It hasn't seen any use until now.I have it in the 2009 Holiday Video.The outer is the 5690, inner is the 224, between them is the Goose,on top is the 248. The trolley is the 8604.

Anton, the Radio Shack terminal blocks are about half the size, and they are also, every other hole for pin connections.

I added the footage in, for a request to see more video. I thought I would try something dark to see how the lights show up.
As usual, out of focus.


----------



## tjcruiser

Thanks, T ... nice looking loco ... I really like that streamliner look.

Cheers,

TJ


----------



## T-Man

I didn't have any pictures of the engine readily available, so I added some.
Enjoy.


----------



## tjcruiser

Love it!

I enjoyed looking at your layout video, and being reminded that you're running both O and HO together. What fun! It all fits in perfectly with your "toy train" rather than "pure scale modeling" theme.

And that sailboat of your is racking up some nautical miles under her legs with all of those laps, huh?!?

Thanks, T-Man!

TJ


----------

