Bachmann GRPT140 Service Manual - page 3
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J
J
J
J
J
Operations Description
Display
The following procedures must be executed subsequently in the specified order.
Before turning on the instrument, check the jumpers setting on CPU & SOUND
GENERATOR BOARD to be corresponding to the model accordingly the following table:
MODEL J1 J2 J3 J4
GRPT140 NO YES YES 2-3
RPT115 NO YES YES 2-3
RP-PRO1 NO NO NO 1-2
RP-EXPANDER NO NO YES 1-2
NOTTURNO 126,117,113 YES NO NO 1-2
NOTTURNO 190 YES NO YES 1-2
Remove the secondary fuses F1, F2, F3, F4, located on POWER AMPLIFIER & SUPPLY
BOARD; turn on the instrument and verify the supply AC voltages:
(CN11) between pin1 and pin2 = 27,5±1,5Vac
(CN11) between pin1 and pin3 = 27,5±1,5Vac
(CN11) between pin2 and pin3 = 55±3Vac
(CN2) between pin1 and pin2 = 16±0,8Vac
(CN2) between pin1 and pin3 = 16±0,8Vac
(CN2) between pin2 and pin3 = 32±1,6Vac
Turn off the instrument and put the fuses back on its holders.
Turn on the instrument.
Check the supply DC voltages on CPU & SOUND GENERATOR BOARD:
(CN4) between pin9 and pin6 = +5±0,25Vdc
(CN4) between pin1 and pin4 = +12±0,6Vdc
(CN4) between pin1 and pin5 = -12±0,6Vdc
GRPT140 AUTOTEST PROCEDURE
Operations Description
Display
The instrument starts in AUTOTEST mode turning on the instrument while pressing
down the data "▲" and "▼" buttons.
NOTE: Each time you press the data "▲", button the autotest procedure skips to the
next step.
During the autotest and auto-calibration procedures the instrument does not respond
at any keyboard action.
AUT
The display shows "rot"; rotating the "SOUND" and "EDIT" knobs the first and last
digit show their position in the range from 0 to 5 each.
ROT
5-0
The display shows "pot"; rotating the "VOLUME" knob the three digits show its
position in the range from 0 to 127.
POT
064
The display shows "ped"; pressing the SOFT and SUSTAIN pedals the first and second
digits show F (fully pressed) or 0 (fully released), pressing DAMPER the third digit
changes progressively from 0 (fully released) to F (fully pressed).
PED
00F
The instrument generates a 1KHz sinusoidal signal in both audio channels, verify with
an oscilloscope the signal at the outputs.
Phones output without load = 7.7±0.5Vrms
AUX output = 0.57±0.02Vrms
GRPT140 INITIAL CHECK
The display shows "mid"; connecting MIDI OUT and MIDI IN sockets with a Midi Cable,
the instrument checks the loop showing "LLL" on the display if it is working correctly
or "---" if not.
MID
LLL
The display shows "STP" to confirm the end of Autotest procedure.
Now turn off the instrument if you do not want to calibrate the keyboard.
STP
GRPT140 Keyboard Automatic Calibration
Operations Description
Display
Start with the instrument in AUTOTEST mode as described above and press data "▲"
button until the display shows "ADJ".
ADJ
Press all the natural and sharp keys respecting the following precautions:
1) One or more keys at the same time is not important but each key once at least.
2) Play the keys slowly with PPP (pianissimo) action as uniform as possible for whole
keyboard extension.
3) Release the keys slowly to avoid any oscillation or vibration.
4) Be sure that all keys are pressed at their end stroke, without apply extra pressure.
ADJ
Pressing "▲" and wait since the instrument memorizes the new calibration.
If you do not hear a note your keyboard is successful calibrated. Press again "▲" and
the instrument will restart in standard operation.
If the instrument play some notes the calibration is not done properly, the keys not
calibrated are notified in order from higher to lower tones, you may hear:
1 tone for each key note that has upper threshold value too high,
2 tones for each key note that has lower threshold value too low,
3 tones for each key note that has not enough threshold range.
The most frequent reasons are the following, check these in the order specified below:
1) You have not activated one or more keys during the auto-calibration procedure.
Solution: repeat the auto-calibration procedure from beginning.
2) The optical sensors are dirty.
Solution: check these disassembling the keyboard, clean the optical sensors
with a cotton flock slightly soaked with denaturated alcool, reassemble the
keyboard and finally repeat the auto-calibration procedure.
3) The optical sensor are out of the tolerance range.
Solution: disassemble the keyboard and replace on the contacts board the optical
sensor that does not work properly, reassemble the keyboard and check it
repeating the auto-calibration procedure.
Note: Execute a calibration everytime the boards 810559,810560,810451 and 761148 are repaired or replaced and each
time you consider it may be required, such as: keys replacement, keys re-alignament, climatic temperature very hot or
very cold respect the ambient standard temperature of 25°c.