I have looked the diagram at your current link for modifying the reverse board to always start in the forward direction. The board in my older Pennsy F Unit does not look anything like the one in your link. Do you have diagrams for other versions of the board ?
Tks
Rick
Hi Rick,
Yes there is a way. I will look through my older documentation and email it to you if I can find it. Look for a revision number (i.e. REV 1, REV 2 etc) on the board and let me know what board you have.
Regards,
3rail
I did not notice any markings while I had it appart. It may be a couple weeks until I can get back to it. I did take a (not too clear) picture of it with my phone that I can send. Haven't had much luck yet, and it keeps clearing my text. I will try it again with an empty message. If I cant the picture through. and you think it will help, let me know I can send it.
Tks again
Rick
I took the shell off the unit again. There were no markings top of the circuit card. I did not pry the card off the mounting sponge because I do not have any double sided tape handy, but I did find a date etched into the card on 1 edge. The date was 2/84. Is this the rev you are looking for, or do I have to do additional disassembly ?
Tks
Rick
Rick,
I have been trying to locate the older diagrams, but have not found them yet. Is there anyway that you could take a photo of the board and post it?
Regards,
3rail
I tried this with an earlier post, and got the same message as tonight. I am trying to sent the picture as an attachment and get the following:
"The upload folder is full. Please try a smaller file and/or contact an administrator. " The file is smaller than the indicated size. Is there some other way I should be sending it ?
Tks
Rick
Hi Rick,
Our photo gallery is not set up for uploads at this time. Most people use an outside service like photobucket etc. Cut and paste the URL of your picture from your service to your post, highlight the text of the URL in your post then you click on the Insert image icon (bottom row second from the left looks like a picture frame) to post the code. Hit the preview button to make sure that it works OK
Best Regards,
3rail
OK. Sorry for the delay. I took the shell back off and took a couple good pictures of the card. I posted them temporary on my blog, since I havent used the other services. Hope this works, since the preview button is not showing them. Here are the links:
http://4.bp.blogspot.com/_f_8YATKP-a0/Sic08aiRgVI/AAAAAAAAAYQ/joOO8SyhPbI/s1600-h/DSC08295.JPG
http://4.bp.blogspot.com/_f_8YATKP-a0/Sic08aiRgVI/AAAAAAAAAYQ/joOO8SyhPbI/s1600-h/DSC08296.JPG
http://4.bp.blogspot.com/_f_8YATKP-a0/Sic08aiRgVI/AAAAAAAAAYQ/joOO8SyhPbI/s1600-h/DSC08297.JPG
Hi Rick,
That is the first generation reverse board circa 1980's. I don't think it has that feature, but I will dig in my achieve info to see if it is possible.
Regards,
3rail
Dear All,
Here is a brute force method bypassing the board. Flip the switch back for normal operation.
Buy a 6 amp DPDT switch.
1.) Cut the 4 wires between the board and the DC motors. (Front motor plus(+) and minus(-), rear motor plus(+) and minus(-).)
1 2 3
4 5 6 <-- Back of DPDT switch
2.) Wire the DPDT terminals as follows.
1. Board "motor +" output (2 wires)
2. Front and back motor + (2 wires)
3. Board rectifier bridge + output (solder wire to foil side of board)
4. Board "motor -" output (2 wires)
5. Front and back motor - (2 wires)
6. Board rectifier bridge - output (solder wire to foil side of board)
3.) Re-check your wiring/soldering, being careful that no terminals are shorted (bridged) on the back of the DPDT switch, and that no foils are shorted (bridged) on the back of the board.
4.) If constant direction is backwards instead of forward, swap wires on DPDT terminals 3 and 6.
5.) Use electricians tape or large diameter shrink tubing to insulate the 6 switch terminals.
Hope this helps,
Sincerely,
Joe Satnik
Hi Joe,
Good suggestion, but this assumes that there is power supplied to the bridge rectifier in all modes. I am not sure that this is the case with this older board. The board is still powered and will still cycle when power is interupted, you are just redirecting the output to the motors. If the is the bridge is not powered in neutral, your method will not work.
You could add a separate bridge wired directly to the AC input and then use the output to terminals 3 & 6 like you suggest That would definitely work.
Best Regards,
3rail
Dear 3rail,
Yes, an additional rectifier bridge would work. You would have to find and tap into the rail power pickup wires (center rail, outside rails) and send the center rail pickup to one of the ~ (AC) bridge inputs, and the outside rails pickup to the other ~ (AC) bridge input.
Most electronics run on DC, and your recent Williams motors are DC. I'm assuming your old motors are too.
I am guessing that the first and only component Williams has (fed by the track AC) on the printed circuit board is a bridge to rectify the track AC, therefore making an additional rectifier bridge redundant.
I could be wrong, though.
Your method (additional rectifier) would be more straight forward, and you wouldn't have to solder to the PC board.
The more "elegant" solution (non-brute force method) would be to modify the 4-step sequencer logic (i.e, modify the PC board) to only allow the "forward" step to happen, or put a switch in that forces the logic to choose either "4-step" (normal) or "forward only" running.
If you don't have a schematic, though, you would have to reverse engineer the board. That would be difficult without the board in your hands, or a good, traceable foil side photo of the board and a part number for the sequencer IC.
3rail,
Has the sequencer IC stayed the same throughout the years?
Hope this helps.
Sincerely,
Joe Satnik
Edit: Added italics.
Bump.
I have modified my last post so much that it may as well be a new post.
For board mods, I suppose you really don't need to know what the sequencing chip is.
You could just hijack the inputs to the power Darlingtons. (X marks the spot.)
Track --> bridge ---> sequencer --X--> Darlingtons ---> motors
l--------------->----------------^
Hi Joe,
Thanks for the input. You brute force method is worth a try for those who have an older board because I have no idea what components were used. It will most probably work. The newer boards have 2 bridges, but I have the diagram for those.
Best Regards,
3rail
Joe / 3rail,
Thanks for you time and suggestions. Believe I'll just run it in regular mode for now, and use another engine for what I was trying to do.
Rick
What I have done to lock a Williams engine in forward is to remove the circuit board completely(in other words, gut the engine and put in only the bridge rectifier)and put in a 6 amp 50 volt or higher bridge rectifier and wire it straight from the center rail to one unmarked terminal on the rectifier and wire the ground or frame to the other unmarked terminal on the rectifier and wire the motors from the bridge rectifier negative and positive posts to the motors, be sure to keep the same colored wires together coming off the rectifier. Be sure you know which way the motors are going before you solder the connections if you do solder.
For lights you can wire them straight from the track pickup and use a 14 volt bulb from Radio Shack. Standard light bulbs don't care if it is A.C. or D.C. but not so if you are using newer low watt bulbs.
Lee F.
I have successfully used your published instructions to lock one engine with a Rev 4 board in forward only and it works great.
I also need to do this to a slightly older GP-38. The board looks similar to the Rev 4 board but it does not have the connectors on the board. The wires from the motors are directly wired to the board nad not in connectors. Also the resistor layout looks slightly different. Is there a way to rework this board to lock it in forward, aside from the brute force method you mentioned earlier?
Dear West Texan,
The mod on that board IS NOT the same. I am pretty sure it will result in a direct short. I will check to see if we have the documentation on that board and post it if we do.
Regards,
3Rail