ULTRATHERM 908i
25
gbo Medizintechnik AG 2004
Version 1.2
5. Service instructions
5.1. Function check of the power generator A200
In case of troubles these instructions can be used for troubleshooting and for the determination of
whether the power generator correctly operates or not. It shall be possible to localise the trouble up
to the corresponding faulty subassembly.
ATTENTION:
The setting components on the PCB (except R202 and R255) shall not be
readjusted because special measuring instruments are required for the
different setting values!
Measurement conditions:
If not given elsewhere, all voltages given are to be measured against
earth.
5.1.1. Check of the supply voltages
Check:
•
+15 V (X206) and -15 V (X209) against earth.
•
The secondary voltages of the mains transformer under no-load conditions, i. e. without any RF
power output:
about 45 V
RMS
between X002.1 and X002.1
about 26 V
RMS
between X002.3 and X002.4.
5.1.2. Readiness for operation of the A200 subassembly
Separate the plug connection X207 and apply earth potential to the control-voltage input U
in
(X207), i. e. RF power is not delivered.
Then measure the following voltages:
•
Power supply
A voltage of about +13 V appears at X205. This voltage is superimposed by a serrated voltage of
about 3 V and irregular period in the second range. At its pin 15 the integrated circuit N203
delivers an internally generated reference voltage of about -8.2 V measured against X205.
•
Voltage of the level control
A voltage of about 0 V appears at the basis of V210, thus, the level control is blocked.
•
Analogous computer
