Section 5 MAINTENANCE AND TROUBLESHOOTING
GENERAL
Should any difficulties be encountered in the use of your instrument, it is recommended that you contact any author-
ized MKS Sales Office or Home Office for repair instructions.
IF IT IS NECESSARY TO RETURN THE INSTRUMENT TO MKS FOR REPAIR, PLEASE
CONTACT MKS' CUSTOMER SERVICE REPRESENTATIVE AT THE NEAREST MKS SERVICE
CENTER FOR AN ERA NO. (EQUIPMENT RETURN AUTHORIZATION NUMBER) TO EXPEDITE
HANDLING AND ASSURE PROPER SERVICING OF YOUR INSTRUMENT. SEE LIST OF
SERVICE CENTERS INSIDE BACK COVER.
TROUBLESHOOTING
Should difficulties be encountered in the use of any 270 system, information in this section should help to isolate
the source of the problem. Whenever similar equipment is available the method of substitution is recommended.
If the pressure reading is overranged >11V, or otherwise suspect, make the checks listed below:
Check to be sure that all vacuum fittings are tight and that the sensor is properly pumped down. Low range absolute
sensors (100mmHg and below) will be overranged at atmospheric pressure.
Connect another meter, analog or digital, to the output to verify the proper operation of the panel meter in the 270.
Place the RANGE SELECTOR in the SYSTEM CHECK position, DISPLAY UNITS selector in the mmHg position,
and perform the following checks:
Does the system check read
properly? See cal sheet for
system check value.
NO
11P
Problem may be in sensor
electronics, cable or 270.
Do test A. Does it pass?
NO
Problem may be cable or
270. Do test
B.
Does it pass?
NO
*
Problem is in the 270.
Place RANGE SELECTOR
in Full Scale. Does it work
properly?
NO
The problem is internal to
the 270.
Problem is in the
YES s e n s o r mechanics
YES
-
1
0
YES
Problem is in the
sensor mechanics
olProblem is in the
s e n s o r cable
Problem is in the input
YES
-
c i r c u i t s of the 270
5-1
