Specifications

GOLDCUP CONTROLS SERIES 700
FEEDBACK FOR 700 SERIES
HI-IQ SERVOVALVE CONTROL
S23-02345 Potentiometer feedback
for 7E & 7G controls
S23-03278 D.C. R.V.D.T.feedback for
7F & 7 H controls
DESCRIPTION
DISASSEMBLY
See Figure 7
REWORK OF WEAR PARTS
PREPARATION FOR ASSEMBLY
ASSEMBLY
The feedback controls provide an electrical signal corresponding to the pump displace-
ment. For the potentiometer feedback, this signal is typically +/- 3.1 volts at full stroke,
with a +/- 15 volt input.
The RVDT has internal circuitry to power the RVDT and demodulate the output, con-
verting the rotary input into a proportional D.C. output of +/- 2.3 volts at full stroke with
+/- 15 volt input.
Remove studs (12) by turning nuts (13) and remove cover (11), cover ring (33) if
applicable, and housing (28).
2. Remove connector (22). Unsolder all wires from this connector.
3. Remove screw (27) attaching link (26) to cover.
4. Loosen the nut on the shaft lock (6), closest to the potentiometer or RVDT.
Remove potentiometer or RVDT with mounting plate (7).
5. If complete disassembly is required, apply heat to the shaft lock (6), approx. 350°F.
(176°C), to soften loctite and permit unscrewing from shaft.
6. Remove retaining ring (21) and press the shaft assembly through the valve body.
7. Examine shoes (1) and (4) for contamination in balance pads or excessive scratch-
ing on faces. Note: the two shoes are not identical and must be installed in the proper
position on reassembly.
All parts are to be inspected and be free of material defects, dirt, scratches or any for-
eign material. All parts are to be cleaned with a suitable cleaning solvent and all cores
and passages blown out with clean dry compressed air.
After cleaning and inspection, all parts are to be covered with a light film of oil and
should be protected from dirt and excessive handling until assembled onto the unit.
During assembly, lapped and ground surfaces should be kept lubricated and protected
from nicks or surface damage.
1. Apply pipe sealant and Install plug (19) in body. Torque to 100 lbs-in. (11.3 Nm)
2. Install O-ring (2) in groove of shear seal (4). Install shear seal with O-ring in the
large hole on the servo link, on the servo shaft side. Be certain that the shear seal is
sitting with the flange flush against the servo link surface.
3. Install three thrust washers (17) over servo shaft and seat against the servo link.
4. Install O-ring (5) in the second groove from the end of the shaft, using installation
tool T-1.
5. Install the servo shaft assembly into the cover plate (18).
6. Install retaining ring (21) into the groove of the servo shaft extending through the
cover plate.
7. Place a drop of Loctite #271 on the threads on the end of the servo shaft. Install
shaft lock (6) onto the servo shaft.
8. Using rosin flux solder, attach wires to potentiometer according to the wiring dia-
gram, allowing sufficient length to wrap around once, plus 5” (127 mm) extra length.
9. Assemble brace (26) onto mounting plate (7), on side opposite counterbore, using
screw (31) and locking nut (32). Hand tighten only.
10. Assemble RVDT or pot. into the counterbore on the mounting plate (7). Install
mounting cleats and screws (8).
66
Description Rework
Servo plate face Fine stone to remove raised burrs & dings
Shear seal Fine stone to remove raised burrs & dings. Note:
grooves to supply balance pads must be present
and adequate.
Control cover Stone or lap inside face to remove raised burrs &
dings.
Note: The shear seal will fit in one position only. Otherwise one side will be held up
by the lip of the servo link. Shear seal (4) must be installed to face against the cover
plate (18). This shear seal differs from shear seal (1) in that the face surface is ma-
chined with two .094” (2.4 mm) radius scallops.