Minolta XD-11, Руководство по ремонту

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EXPOSURE AND READOUT
ADJUSTMENTS
For many of the repairs in the XD-11,
you w o n 't have to disassemble the
camera any further than we've described.
The modular construction then makes the
camera fast to service. Let's say you've
replaced the fro n t-p la te /m irro r-c a g e
assembly. You're then ready to make the
adjustments.
Remember that you should avoid dis­
turbing the tw o variable resistors for the
LED readout — Rx5 and Rx6, Fig. 48. Set­
ting up the other adjustments should bring
in the accuracy of the LED display. But, if
the LED readout remains off by more than
1 EV, you can pull out the front-plate/-
mirror-cage assembly far enough to reach
the variable resistors. It's also possible —
though not recommended — to reach the
adjustments through the cutout on the
side of the lens mount. Using a curved tool
to turn the "blind” variable resistors could
do more harm than good.
Start by checking the MD common volt­
age, Fig. 54. We described the test during
troubleshooting. As you'll recall, you
should measure from 1.1 to 2.2V w ithout a
lens installed. There's no adjustment on
the MD common voltage other than shift­
ing the m inim um -aperture resistor.
However, if you aren't getting the MD
common voltage, you w on 't be able to ad­
just the LED readout in the S mode.
CALIBRATING THE MANUAL
SHUTTER SPEEDS
The tw o variable resistors at the front
of the flex circuit. Fig. 69, provide your
adjustments for the manual speeds. Rx7
adjusts the constant-current source. W ith
the proper amount of current to the tim ­
ing circuit, the shutter speeds should be
linear.
Set the mode switch to M. Then con­
nect a digital voltmeter between Rx7 and
fixed resistor R56 as shown in Fig. 69.
Depress the release button part way to
measure the voltage.
You should get a reading of 180mv
(0.180V) ± 2 m v. If not, make the adjust­
ment using Rx7. Turning the wiper of Rx7
in a clockwise direction causes the
voltage to increase.
Now use variable resistor Rx3, Fig. 69,
to adjust the manual 1/30-second shutter
speed. Minolta recommends setting the
exposure time to 31.2ms. The other
manually calibrated shutter speeds should
then time properly.
But you'll sometimes find that the
fastest speed — 1/1000 second — re­
mains too slow. In that case, check first
the blade-travel times. The blades should
cross a 20mm distance in 6ms. If not,
you'll have to remove the shutter and ad­
just the blade tensions.
There's one more adjustment that af­
fects 1/1000 second — the eccentric for
the shutter's trigger switch. Changing the
moment at which the trigger switch
opens has a significant effect on 1/1000
second. But the adjustment has very little
effect on the other shutter speeds.
It’s possible — albeit delicate — to ad­
just the trigger switch w itho u t removing
the shutter. You can reach the eccentric
through the clearance cutout shown in
Fig. 70, However, you're again faced with
a "b lin d " adjustment.
Later, after we remove the shutter,
we'll go through another technique you
can use to adjust the trigger switch —
one that involves adjusting the eccentric
for 1/1000 second before replacing the
shutter. Still, you w o n 't w ant to remove
the shutter for every XD-11 repair. You
may then have to use the clearance
cutout, Fig. 70, to adjust 1/1000 second.
ADJUSTING THE ASA INCLINATION
Variable resistor Rx1, Fig. 71, sets the
A S A inclination — the actual signal
change for a change in the film-speed set­
ting. Properly adjusting the A SA inclina­
tion should eliminate the need to disturb
Figure 69
Figure 70
Figure 71