Service manual

- alsa apparecchi medicali s.r.l. -
Pag. 3
concerning the part that could be damaged and that needs adjusting in order to restore the complete
efficiency of the unit.
ALARM CODE PROBLEM
blinking displays Device continuously activated for more than 30 seconds
ErrNP
Neutral plate connection problem
ErrACt
Activation error (two activation switches pressed at the same time or wrong activation
compared to the functions selected on the control panel)
ErrPED
Pedal switch pressed when the device was turned on
ErrHND
Hand switch pressed when the device was turned on
Err21
Push button on control panel pressed when the device was turned on
Err1
General system error
ErrIIC
Communication problems between the peripheral units
ErrHt1
Over heating in the RF section
ErrHt2
Over heating in the power supply section
ErrUP2
“Slave” microcontroller trouble
ErrAL5
Fault of the +5V power supply of both microcontroller
ErrNPC
Fault of neutral plate alarm circuit (inside the unit)
ErrAD2
Conversion problems in the digital converter of the “slave” microcontroller
Err9
Fault of power supply control in the monopolar RF section
ErrIO
Fault of power supply control in the bipolar RF section
ErrII
Fault of RF modulation signal control
ErrI2
Fault of reading signal of the monopolar power control
ErrI3
Fault of reading signal of the monopolar power in the “spray” mode control
ErrI4
Fault of reading signal of the bipolar power control
ErrI5
Problems about internal RAM of both microcontrollers
ErrI6
Fault of EPROM CRC control
ErrI7
Fault of EEPROM data integrity control
Err2O
Fault of master watchdog timer
Err23
(available)
Err25
System variables complementation error
Err27
Problems in reading the effective output current
Err28
Output peak voltage reading problems
Err30
Problems in the voltage reference of the neutral plate alarm circuit
The H.F. power section consists of an oscillating circuit composed by four MOS-FETS (type IRFPE50)
connected in parallel (in order to obtain the maximum output power), each of which is driven separately by a
MOS-FET driver (type MAX 4420). By means of this oscillating circuit the variable continuous voltage coming
from the power unit section is “transformed” into a sinusoidal wave form with frequency of 475 kHz and the
power is then transferred (from the L7 inductor) to the output transformers (monopolar and bipolar) on the
Mother board. An additional MOS-FET on the same board cuts off the pulses when the unit is activated with
open circuit. The driving signals for this section come from the R.F. driver board, on which a UC 3825 PWM
driver circuit can pick-up (depending on the function settings on the front panel) one of the three ramp
signals used to provide a different pulse width according to the wave form selected (type of performance for
example cut, coag. …). This ramp signal, supplied by the square wave of the local oscillator at 950 kHz , is
sent to the Microcontroller board circuits U5-U6 (74HCT4040 and 16V8 PLD respectively), and it is set using
the R13, R14 and R15 pots in order to obtain the pulse width desired. On the microcontroller board there is
also the acoustic alarm section.