ORTEC 473 - Factory Repair; Fig. 7.4. Test Setup for Ge(Li) Mode Walk Test

19
0RTEC448
Pulse Ht.
Normalize
Relay
Pulse/Sec.
Risetlme
- (Adjust)
- (Adjust/
- Int Osc
- 100
- BO
Time Const. Decay - 50
Polarity - Pos.
Atteii. - (Adjust)
Oiii|itn
lt!St
KC/li2
ORTEC 276
100
I—vw
—1— RR/f
RG/6
Preamp
2
ORTEC454
CG - 5 to 10
FG - (Adjust)
Int. - 10
Diff.-20
Pos.
Thru Sig.
I
In.
CT3
Trigger
5 V.t.s!30 ns
Pos. Ext. Trigger
(IMeg)
RG/62
425
^4 ns
SCOPE
Pos. Out
Start
ORTEC457
TEK 50 0HM
STEP
ATTENUATOR
ORTEC 473
GelLI)
0.050 V (CCW)
CE
(Neg.)
Out
Stop
Rng.
- 0.1
CG - 2
Multi - 1
FG - (Adjust)
Bias
(Adjust)
Gate
- Ami,
Strobe
- Int,
NOTE: All cables are 50 ohm coax {RG/56) unless otherwise specified.
Fig. 7.4. Test Setup for GelLi) Mode Walk Test.
5. Adjust the 457 Bias and Fine Gain until a change of 4 ns corresponds to a change of 1 V (2 divisions) on the oscilloscope.
This calibrates the system so that one major division on the oscilloscope is equal to 2 ns.
6. Change the attenuator in the following sequence while observing the oscilloscope: X2X5, X5X10, X2X10, X10, X5, XI.
7. Adjust R32 as necessary so that the output amplitude from the 457 changes no more than 4 ns (2 divisions) for the
attenuator changes in step 6.
8. If multipulsing occurs when the attenuator is set at XI in step 6, turn the 473 front panel Disc Level control to about 200
dial divisions, for 200 mV; the multipulsing should disappear.
7.7. FACTORY REPAIR
This instrument can be returned to the ORTEC factory for service and repair at a nominal cost. Our standard procedure for
repair ensures that the same quality control and checkout are used that would be used for a new instrument. Always contact
the Customer Service Department at ORTEC, (61 5) 482-4411, before sending in an instrument for repair to obtain shipping
instructions and so that the required Return Authorization Number can be assigned to the unit. This number should be
written on the address label and on the package to ensure prompt attention when the shipment reaches the factory.