Operating instructions
6.1.9 Reel Tension Servo Adjustments
Before these adjustments can be performed, the swing arm adjustments
and/or voltage measurements should be checked. Refer to § 6.1.5.
6.1.9.1 Upper and Lower Limit Adjustment of Reel Tension
Steps 2 and 3 are necessary only if either or both tension arm assemblies
have been disassembled.
1. Turn the power off. Remove the Transport Deck Plate (§ 6.1.1.2).
2. With the power off, extend the REEL CONTROL PCB Assembly. Turn the
power on and monitor TP3 or TP4 (Take-up and Supply respectively)
with a DC Voltmeter (DVM or VOM) using a Ground test point on the
same PCB Assembly.
3. Mechanically adjust the swing arm potentiometer located under the deck
plate by loosening the screws while securing the arms at the center
position so that the DC Voltmeter indicates 0 V. Refer to § 6.1.5.
4. Turn the power on, if it is not already on. With the Take-up swing arm at
its resting (lower) position, adjust the T.UP LOWER trimmer (VR10)
(sixth from the top on the REEL CONTROL PCB Assembly) until the
yellow indicator above it turns on. Adjust VR10 so that the yellow
LOWER indicator is illuminating until the Take-up swing arm moves up 2
mm from its resting position.
5. Move the Take-up swing arm just to the position at which the yellow
LOWER indicator goes dark and hold it there.
6. Adjust the T.UP UPPER trimmer (fifth from the top of the REEL
CONTROL PCB Assembly) until the green indicator above it turns on.
NOTE: After steps 4 to 6 have been completed, make sure that the upper and
lower LEDs do not illuminate at the same time while moving the swing arm.
7. Repeat Steps 4 through 6 for the Supply swing arm adjusting the SUP
UPPER and SUP LOWER trimmers (next to the bottom and on the
bottom of the PCB Assembly). It is good practice to adjust the settings
of the UPPER trimmers and green LEDs to be as balanced as possible
between Take-up and Supply arms.
T.UP
POS
GAIN
L
M
H
UPPER
LOWER
SUP
POS
GAIN
L
M
H
UPPER
LOWER
REEL
CONTROL
Figure 6-9
REEL CONTROL PCA Front Panel
Section 6 Alignment
6 - 12
October 1990
MTR-90III Operation and Maintenance Manual