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Aspiring Boat Bum
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Discussion Starter #1
Have an old W-H autopilot, model P-3A that was given to me a few years ago,

Finally putting it all together and all is good except for one piece that is not shown in any of the manuals I have.

The mystery box is labeled Model VD-1. It appears that this would function to activate the clutch solenoid or a solenoid operate hydraulic valve in the drive system. Since there is no other connection or output from any of the other modules by default this has to be the purpose.

The VD-1 has five terminals:

12V
Ground
SOL
SOL
Turn On.

The first two are obvious, even more so that there are the ends of two severed wires that match two other ends on the main controler where the 12V power is supplied.

SOL and SOL must be outputs to a solenoid. I tested them with power to the unit. No voltage until I applied 12V to the Turn On terminal, then I got 12V across the SOL terminals.

So 99% certain I've figured out the VD-1 box but I don't see where to connect it to the system. The AP has three modes: OFF, Standby, Drive. Need to access a line somewhere that outputs 12V when the AP is in Drive mode and 0V when in Standby or OFF.

Problem is there are no open plugs or terminals on any of the other boxes in the system. There is one mystery cable with 9 wires inside that is unattached and has no plug on the end. This cable is also not mentioned or shown in any of the manuals.

So anyone have any suggestions as to where or how to connect the VD-1 box so it will control the clutch on my drive motor?


Thanks
Skip
 

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After you put 12V on the ON terminal and got 12V on the SOL terminals, did you see what happens to the SOL when the AP is put on STDBY and OFF?

The ON terminal might just be a missing external switch. Otherwise, it seems like it should be connected to whatever relay STDBY is activating.

I'm not sure from your description where OFF/STDBY/DRIVE controls are located - the VD-1 box?

Mark
 

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Aspiring Boat Bum
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Discussion Starter #3
Hi Mark,

Thanks for the reply. I'll post a wiring diagram and a complete description of how it's wired so you can see the whole picture.

Notes:

- Every terminal, wire and cable on any box in the system is drawn and labeled on the diagram.

- There is one mystery cable with nine wires coming out of the PHC. It comes from the inside of the box and the other end is bare so no plugs on either end. This cable is not shown or mentioned in any manual.

- The connections between the boxes are multi-lead cables with unique plugs on each one so they fit only into the correct (and labeled) sockets on the boxes.

- All individual terminals are all labeled.

- There no are unknown or unused wires, plugs, sockets, or terminals in the system except the mystery cable from the PHC and the Turn On terminal on the VD-1 box

PHC

- Pilot House Control. This has the On/Off switch, Drive/Standby, Course set, yaw control, etc. Has inputs from the compass and remote control. Has a cable to the Junction box that is an in/out sending AP control information through the JB to the Motor Control and getting 12V power in from the JB.

Motor Control

- This is the brain AND power out to the drive motor so has large gauge connections to motor and the battery.

Compass Electronics Box

- Converts output from the compass to an electronic signal to feed into the PHC.

Junction Box

- Inputs from the PHC, rudder angle sensor and separate 12V power to the electronics part of the AP. Output to the Motor Control (aka brain). In addition to the cables with plugs connecting to the Motor Control and PHC there is a five place terminal strip. Three terminals connect to the cable going to the rudder angle sensor. The other two are marked 12VDC input +/-.

- On the 12V terminals there are two cut wires on each lug. One pair went to the battery to supply power to the electronics of the AP. The other pair matches two cut wires coming off the the VD-1 box.

VD-1

- Has five terminals. 12v, Ground, SOL, SOL, Turn On.

- 12v and Ground and have cut wires still attached that match the cut off wires on the Junction Box 12v power connections.

- I tested the VD-1 box as follows:
1. Connected power to the 12V and Ground
2. Checked voltage between SOL and SOL got no reading
3. Connected 12v to the Turn On terminal
4. Checked voltage between SOL and SOL and got 12v.

- From this the VD-1 clearly was intended to activate some external solenoid. Since there is no other wire, cable or connection in the system that could operate a clutch on an electric drive motor or a solenoid operated valve in a hydraulic drive system the VD-1 must have been intended for this function.

- The problem is, there is no cable, terminal or missing connection anywhere the VD-1 could be connected. What I need is a connection that goes to 12V when the AP is in Drive mode and no voltage when Off or Standby.

Unless you have a better manual or more info about this system than I then I'll just have to hook it up and start testing wires and connections while I play with the buttons.
 

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That picture clears up the description. Just a WAG, but I think the pilot was never designed to control a drive unit with a clutch, and the VD-1 was an attempt to make it do so in a bit of a crude manner. I think there was an external switch on the "turn on" terminal, where you would flip the switch on when you wanted to use the AP, and off when you were finished.

I think the 9 wire mystery cable may be a data communication or similar function. Possibly a wired remote control that was cut to remove? Particularly if they are small gauge wires. I don't know anything about this AP, so don't know if it was designed to communicate with other equipment. It is possible that they control the VD-1 somehow, but if all of the other cables have dedicated and purposeful connectors, then it is unlikely they just winged it with this particular function.

If my hunch on the VD-1 is correct, it seems like you should be able to open the junction box, determine which connection inside is powered when the AP is in "ON" mode AND unpowered when the AP is in "STDBY" mode, and connect the "turn on" terminal of the VD-1 to that. This way, the AP would power the clutch when ON, and turn it off when in STDBY or OFF.

My only other thought is that maybe you don't have a complete system and are missing a part that ties the 9-wires and VD-1 into the rest of the system you do have.

Mark
 

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Aspiring Boat Bum
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Discussion Starter #5
That picture clears up the description. Just a WAG, but I think the pilot was never designed to control a drive unit with a clutch, and the VD-1 was an attempt to make it do so in a bit of a crude manner. I think there was an external switch on the "turn on" terminal, where you would flip the switch on when you wanted to use the AP, and off when you were finished.
My WAG as well BUT in the manuals I have there is another box shown that I don't have and don't quite understand. It is labeled ON/OFF Valve and it is wired into the + 12V DC wire between the battery and the Junction Box in the diagram. By that I mean the battery + connects to one terminal on the ON/OFF Valve and a wire goes from the other terminal on the Valve to the +12V DC terminal on the Junction Box, like you might wire a power switch into a system. The ON/OFF valve according to the manual actives the hydraulic valve that controls the hydraulic AP drive so probably closes the bypass valve so the pump can drive a hydraulic cylinder.

My thought on this is that a 12V output doesn't know if it's activating a solenoid connected to an electric clutch or a hydraulic valve, it's all the same. What I don't understand is how this would work just on the +12V line unless that line draws current only when the AP is in Drive mode which seems odd since that is the power to all the electronics of the AP.


I think the 9 wire mystery cable may be a data communication or similar function. Possibly a wired remote control that was cut to remove? Particularly if they are small gauge wires. I don't know anything about this AP, so don't know if it was designed to communicate with other equipment. It is possible that they control the VD-1 somehow, but if all of the other cables have dedicated and purposeful connectors, then it is unlikely they just winged it with this particular function.
Agree that the mystery wire is probably some kind of comm cable, maybe an early NMEA0183. The AP I believe was originally made in the late 1990s so the timing would work. Since there is already a wired remote connected to the system doubt this would be a connection for another one.

W-H had a rep as a very solid, commercial grade unit, used by a lot of fishermen in the NW so can't imagine they would cobble something together or require you to use a separate, external switch to control the motor clutch or hydraulic valve.

Since I see no other unused terminals or connections anywhere I'm left with two conclusions. Since the diagram in the manual shows something in the 12V line to the system maybe there is something happening there although I seriously doubt it. That leaves the mystery cable with it's nine wires.

Unless some W-H expert pops up I'll just hook it up and start testing voltages.

Thanks a lot for the ideas and suggestions.

By the way, I ended up keeping the Raymarine linear electric drive right under my bunk in the aft cabin and cannot hear it at all.
 
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