MOBILETT Plus HP
SPR8-220.061.03
Page 2 of 12
Siemens AG
Rev. 03
09.03
CS PS 24
Medical Solutions
6 - 2
HT and single tank error diagnosis
Malfunction in the inverter or single tank
6
The following procedure will help you to determine whether the problem is caused by the
inverter or the single tank.
The current flow between the inverter and the single tank must be approx. symmet-
rical. If this is not the case, the inverter is defective.
Measure the resistance between K63/POS and K64/1 or K64/2 or K63/NEG and K64/1 or
K64/2. The value must be larger than 0.5 Mohm. If the value is less than 100 ohms, the
inverter is defective (transistors in the modules are defective).
The inverter current is always measured using a separate current
transformer between the inverter and single tank.
Measuring the falling edge of the high voltage (in the measurement point HT on D1 board)
Long falling edge (approx. 2 ms)
Measuring the inverter current
(separate current transformer between
Short falling edge (approx. 50
µ
s
)
(tube arcing)
)
inverter and single tank)
))
Asymmetrical inverter current, e.g.
one-sided or one half-wave significantly
lower (diff. >50%), or no current can be
measured
Symmetrical current and current
>300A (see Figs. 3 and 4).
Inverter or cable
K64 defective
Single tank or
cable K64
defective
Single tank or
cable K64
defective
NOTE