GEM Powerstation SK760, Руководство по обслуживанию

Страница: 27 / 29

27 27
27 27
27
J J J J J
Test Procedure and Adjustment
The procedures that follow must be executed subsequently in
the order specified.
These procedures are not intended to repair a fault but only to
check the correct instrument operations after a repairing execu-
tion.
Test Instruments
þ Dual trace oscilloscope
þ Digital Multimeter
Accessories
þ 8Mbyte DRAM module
þ 2Mbyte DRAM module
þ 2 x 4Mbyte SIMM DRAM modules
þ 1 Hard Disk Kit
þ 1 Vocal Processor Kit
þ 1 3.5inch Diskette
þ 1 SCSI Kit
þ Read/write SCSI device (ZIP, JAZ, Hard disk etc )
þ RS232 loopback (terminal 1-2 and 3-5 shorted)
þ 2 jack-jack cables with a resistor divider inside plugs (10K/
82ohm).
To check completely the keyboard are necessaries all the
optional accessories installed, normally this keyboard have
installed from the manufacturer the 2Mbyte DRAM module only.
Setup
Install all the optional accessories: Hard disk and its 2Mbyte
module (CN9), 8Mbyte module instead the pre-installed 2Mbyte
module on Sample Dram connector CN5, the 2 SIMM modules,
the SCSI and the Vocal processor kits, insert the diskette into
3.5" disk drive.
Set the jumpers on CPU board as follow: J1 at position B and J2
at position 8MB.
Set the JP1 and JP2 jumpers on Supply or Mixer board at position
A.
Connect the R and L outputs to the MIC/LINE inputs using the
appropriate cable.
Connect the external SCSI device to the SCSI socket.
Plug the RS232 loopback into the socket.
Checks and Adjustments
þ
Aftertouch
To adjust the keyboard aftertouch locate the VR1 trimmer on
CPU board, connect the scope CH1 probe tip to its center
terminal, probe clip connected at ground, adjust VR1 to obtain
an excursion from 0 to 5V every time a note key is pressed with
different pressure, or to obtain a better adjustment follow the
instructions on ADJUSTMENT TABLE (page 10 or 12).
þ
MIDI, RS232 and RS422 mode
Press GENERAL and go to page 3 using the page scroll keys,
select MODE(F8) and set PC1 with cursor keys, press ENTER to
confirm; press MIDI, select COMMON/ARRG.(F5) and set Com-
mon Ch. to 1 using the DIAL, press (F7) to set LOCAL OFF, verify
that the keyboard plays thru RS232 by unplugging and re-
inserting the RS232 loopback into the socket.
Press GENERAL and select MODE(F8), select MACINTOSH using
the cursor keys, press ENTER, check the 1MHz clock appear on
pin 1 of COMPUTER socket (use the second probe tip to do that).
Go to page 4 and press SET DATE(F1) button, set the day, month
and year using the DIAL or numeric keypad, press ENTER; also
set the time pressing SET TIME(F2), finally return to the first
page of GENERAL settings.
þ
Panel Key and Led
Press GENERAL, SYSTEM INFO (F2) and (F8) the display show
a warning message: press ENTER to continue, select PANEL
TEST(A) and then press all the panel buttons checking their
operation on display, at the same time every led of pressed
button must light up, except DISK led.
þ
Trackball (Pitch and Modulation)
Rotate the Trackball in vertical way (Modulation) verifying the
excursion displayed, it ranges from 0 to 127.
Rotate the Trackball in horizontal way (Pitch) verifying the
excursion displayed, it ranges from 0 to 127 with 64 on center
position.
A slightly difference may be adjusted by VR11(Pitch) or
VR12(Mod.) on Controls panel board, major differences may be
adjusted repositioning the knob or the potentiometer.
Press ENTER and ESCAPE simultaneously to return to HARD-
WARE test menu.
þ
Memories and Optional Accessories
Press ALL PART (F1), the instrument self-test check subse-
quently the follow devices: SIMM modules (F2 Volatile DRAM),
8Mbyte sample dram (F3 Backed DRAM), Internal Hard Disk (F4
HardDisk), 3.5" disk drive (F5 Floppy Disk), Video interface (F6
Video) and SCSI interface (F7 SCSI Test) and marking with
“Pass” all devices checked successfully, with “Not Present” all
devices not attached, with “Fault” all device defective. Theoreti-
cally all test must be passed, if you have a mistake on a device
re-check its installation.
Press ENTER if necessary.
þ
Inputs, Dsp and Vocal Processor
Put MASTER - INPUT - LEVEL sliders to maximum position and
rotate full clockwise GAIN1 and GAIN2 potentiometer located on
the rear side.
Turn on the 1KHz test tone pressing HARDWARE SET(C), meas-
ure a sinusoidal signal at 4Vpp on OUT 1 and OUT 2 outputs
sockets (the 1KHz tone gets out OUT R and L, re-input thru MIC
1 and 2 by the appropriate cable, pass thru DSPs and finally get
out from OUT 1 and 2).
Turn off the signal by means HARDWARE SET(C).
þ
Noise level
Turn off the instrument, disconnect the signal cable, wait at least
30 seconds, turn on again the keyboard and check the noise level
is acceptable (if not verify the insulation between electrical and
chassis ground is at least 40Kohms).
þ
Data Hold
Press GENERAL, SYSTEM INFO(F2), (F8), ENTER and DATA HOLD
(F8) and then wait until the display show PASS.
Turn off the keyboard and then remove not included optional kits
(the SK base version is equipped with 2Mbyte SAMPLE DRAM
only), restore the jumpers positions: J1 to A, J2 to 2MB, JP1 &
2 to B. Turn on again the instrument and verify, repeating the
test, that only Backed DRAM pass, press ESCAPE.
þ
Final
Verify the keyboard correct operation playing something on it,
finally launch the Demo sequence pressing DEMO and ENTER.
When it is finished you have tested the keyboard.
þ
Reliability Check
Before reassembling the instrument and before deliver it to the
user, it is a goal verify its reliability:
To do that switch it off, or leaving it switched on but operating
with greatest caution, carefully shake the boards and connec-
tions inside it using an insulated tool (for example the handle of
the screwdriver) to find wrong contacts and so on.
Turn on the instrument and verify that it operates correctly
repeating the Final Check.
Disconnect the instrument from the mains, reassemble it and
shake it carefully without causing aesthetics damages, re-
connect it to the mains, turn on and re-check its functionality,
finally leave it switched on for a long time verifing its function-
ality occasionnally.