Crown PSA-2 - Electrical Checkout and Adjustment

crown
7.9 PSA-2/SA2 Electrical Checkout,
Troubleshooting and Adjustment
The following instructions outline an orderly checkout
and troubleshooting procedure. The purpose and
arrangement of this procedure is to determine the cause
of the trouble as quickly as possible; leading to a
detection of which component part(s) must be replaced
or repaired.
Warning!
Most adjustments are made with protective covers
removed. This means prior to any non-ac-powered
testing, discharge all power capacitors; C101, C201,
C102, C202, (See Discharge Instructions; Section 7.5).
Also, use extreme caution while making any internal
adjustments when the unit is powered.
Checkout and Adjustment
Input Signal
Type of Test/ Adjustment Characteristics
1, Turn-on (no AC applied) None
2. Power Supply Voltage None
3. Turn-on Delay None
4. Fan Speed None
Comments
1. Make sure that there is continuity from the rear panel
ground terminal strip to:
a) Test point P on LV Supply Board
b) Test point S on LV Supply Board
c) Barrels of unbalanced input jacks
d) Black binding post of output banana jacks.
With the power switch in the “off” position, connect the
necessary input line power and check accuracy with a
digital voltmeter. Set delay and low frequency protection
slide switches to off.
2. AC power applied; check low and high voltage supplies
with an accurate (+1%) voltmeter. The following voltages
should be observed (See Fig. 6.3 for test points).
a) On the Low Voltage Supply Board:
PinQ — -I5SV
PinR — +15V (+.05V)
PinS — +24V
Pin W -24V (greater than 19V)
b) Between the PNP and NPN Output Board Modules,
150-160V should be measured from pin D of the NPN to
pin E of the NPN. Check both channels.
3. With the delay switch on, turn unit off and then on again
while listening for the “click” of the relays becoming activated.
This process should take approximately four seconds. Also
note the illumination of “Standby” lights at initial turn-on
(they should remain on during the four second delay).
4. Engage high speed by placing a 180K ohm resistor
across pins G & H of each of the four output modules. (If
the 1OC lights are activated at anytime during this test,
it may indicate that a problem exists).