Modify Linc-III to Solenoid

With the ever-increasing difficulty in obtaining parts for the old R-57 vacuum idler controls we are suspending the manufacture of our LINC-III vacuum idler control module for Lincoln R-57 vacuum idler systems.

Over the years we have produced a large amount of these LINC-III types of idler controls and many machines with these old vacuum idler systems currently have them in use. As the mechanical portion of the idler fails it will become necessary to completely modify the vacuum system over to an electrical solenoid system. We currently produce a new LINC-IV to electronically control these types of retrofit systems but owners of our LINC-III can easily modify their current circuit boards to drive solenoids directly. By modifying our LINC-III boards no new wiring is necessary. All required wiring is already in place and only the mechanical apparatus has to be installed.

This procedure shows how to modify the LINC-III to drive (release solenoid on power or weld) systems as currently found on all newer models of large Lincoln engine drives.

Tools required:

Xacto knife or fine pointed knife.

Soldering Iron and rosin core solder. (do not use acid core)

Flush cutting wire cutters or any type of wire cutter that can get in small places.

Several pieces of 24ga wire or smaller.

Procedures:

Remove the LINC-III from the machine. Mark all wiring to where it was originally removed or installed.

Place the circuit board on a table in the position shown below.

Using wire cutters, cut the four (4) components off of the board as shown in figure 1. Cut them from the top of the board----not from the bottom.

Using a soldering iron unsolder the diode (component) from the circuit board. Do not cut it off because you will be inserting a jumper into the place the diode was removed from. Use figures 3 and 4.

Insert a piece of sold wire in place of the diode’s position and solder it into the circuit board. Do not use acid core solder---use only rosin core solder. Use Figure 5 as an example. We used a blue wire to clearly show the wiring attachment.

Turn the circuit board over so that it resembles Figure 6.

Identify pin 8 of the integrated circuit. (Figure 7)

See Figure 8. Using an Xacto knive or fine bladed knife cut the foil (land) on the board that goes from pin 8 (location #1) to the gate of the MOSFET (location #2.) Cut the foil 1/16 ^th of inch just at the point that it attaches to pin 8 of the integrated circuit.

See figure 9. Solder a small piece of wire from point A to point B on the circuit board.

These procedures will complete the modification of the Linc-III to drive a new solenoid system.

Recoat the board and reinstall it.