Shimadzu GCMS-QP2010 Series, Service Manual, Page: 102 / 168

102
Unit Operation Checks
11. RF PS ASSY
Outline
The RF PS ASSY generates the high frequencies applied to the main rod and pre-rod.
As shown in the block diagram, the main rod comprises a pair of opposing poles maintained
at the same potential, to which the following voltages are applied:
A pole = high-frequency (V) + DC voltage (U) + AC voltage (AC) + bias voltage
B pole = high-frequency (-V) + DC voltage (-U) + AC voltage (-AC) + bias voltage
(Where high-frequency = 1.05MHz, AC=52.5kHz.)
Only the high-frequency and bias voltage are applied to the pre-rod.
Operation Check Method
If an abnormality occurs, follow the procedure below to check the operation of the RF PS
ASSY to efficiently diagnose the problem.
Caution
A
±
2500V high-frequency voltage and
±
500VDC are supplied to the RF PS ASSY.
To avoid electric shocks or damage to the assembly, touch only the points instructed.
Caution! Static Electricity
The RF PS ASSY contains parts that are sensitive to electrostatic discharge (ESD).
Static electricity at 4000V or more can easily accumulate on the human body and be
discharged.
D3 to D6 on the RF GENE-A PCB can withstand only 10V static electricity.
Take the appropriate ESD countermeasures when replacing RF GENE-A.
1. Checking the supply voltages
Check the supply voltages. The voltages should be as follows, when the chassis is
grounded.
CP1 +15V (normal range: +14.25 to +15.75VDC)
CP2 -15V (normal range: -14.25 to -15.75VDC)
CP3 +500V (normal range: +510 to +580VDC)
CP5 -500V (normal range: -510 to -580VDC)