TissueLink Aquamantys System, Service Manual

Page: 22 / 65

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4-3
The power supply PCB (Supply_TL1) and the mains transformer
comprise the power supply unit, which is mounted on an aluminum
plate. This power supply unit is fastened in the housing with 4
screws. The mains voltage reaches the Supply_TL1 circuit input
(mains socket, J1) via the line filter socket and the power switch. An
inrush current limiting circuit (consisting of a thermal fuse and power
resistor) is switched in or out by a relay controlled by the “voltage
monitor”. The current limiting circuit is engaged if the mains voltage
falls below 70% of the setpoint for longer than approximately 50 ms
and is switched out when the mains voltage exceeds at least 70% of
the normal mains voltage for approximately 0.5 seconds. The same
percentages and timing apply to the POWER_GOOD signal (see
below).
The voltage selector connects the mains voltage either to the first
115 V winding (115 V operation) or to both primary windings
connected in series (230 V operation). Application of the 100 V
winding (Japan operation) requires a special variant of the power
supply PCB. The “Primary Socket” connector connects the mains
transformer primary winding.
The secondary voltages are rectified (bridge rectifier) and filtered
with electrolytic capacitors.
The voltage monitor drives the current limitation resistor bypass relay
and generates the “POWER_GOOD” signal. In case of a relay failure
the resistor will heat up considerably. A thermal fuse will then
interrupt the circuit and protect the resistor from overheating.
Connector J4 supplies the following unregulated voltages and
signals. From fuse FU3:
•
Approximately 160 VDC (RF generator power stage)
• Approxi/- 28 VDC (small signal components,
pump motor)
•
“Power Good” signal (is issued when the mains voltage has
reached at least approximately 70% of the rated value).
Vital circuits are also protected. The respective fuses are to be found
on the power supply PCB
•
Secondary 115 V winding, FU2: T3.15A (on the secondary
connector)
•
RF generator power stage, FU3: M2.5 A (RF generator
connector)
•
21 V secondary voltages, FU4, FU5 (self-resetting)
•
Low-signal voltages (28 V), FU6, FU7 (self-resetting)
LEDs:
Three LEDs indicate the presence of output voltages and the power
status (POWER-GOOD). The following must be lit:
•
LED1: unregulated operating voltage for RF generator power
stage.
• LED2: positive unregulated operating voltage for RF generator low-
signal stage.
• LED3: negative unregulated operating voltage for RF generator
low-signal stage.