Marconi LORAIN RHM800E50 Manual page 36

ing signal is missing or abnormal, the control and alarm
DANGER
This procedure is performed with power
applied to the recti&?r. Hazardous AC volt-
ages capable of pmducing. severe, perhaps
shock an? present at uwiou~
fatal ekdricd
accidental
exposed electrical termination or with test
equipment cabinets while
Place the POWER swftch to the OFF posi-
tion Do not disconnect AC or DC power
sources.
Remove the lower front panel from the recti-
fier to gain access to both heatsink assert-
firing circuit cards, Part No. 4334-616-66. on
each heatsink assembly.
Adjust the vertical sensitivity of an oscilb-
scope for 5
Adjust horizontal tffe base for 2 millisec-
onds per centfmeter (2 m&m).
DANGER
forming this procedun% otherwise, damags to
shock
personnel
of
equipment becomes eneryized to the same volt-
object when the test equipment is amnected to
it Lf opemting.
the recti~r while
d) Open the meter and control panels by loos-
ening the captive fasteners.
Remove the edge connector from one of the
firing circutt cards. Connect the oscilloscope
Connect the oscilloscope comnwn lead to
rectifier is oper-
per centimeter (5Wcm).
the
Start the rectifier by operating the POWER
oscilloscope. The waveform shoufd be simi-
lar to that shown in Figure 7-2. Amplitude
should be approximately 12 volts peak-to-
peek with a variable time duration depen-
dent upon AC input voltage and output voit-
age settling. The waveform illustrated was
taken with the recttter operating at 206 VAC
input and 52 VDC output with 50% load.
h) After noting the firing waveform characteris-
tics, place the POWER switch to the OFF
position. Disconnect the oscilloscope probe
and replace the edge connector on its
Repeat Steps e) through h) for each remain-
ing firing circuit card input. If the waveshape
at any input edge connector is missing or
abnormal. repface Regulator and Abn cir-
cuit card A7.
When all tests are completed and any nec-
essary repairs accomplished, perform the
following steps:
Completely disconnect all test equtp-
ment leads from the rectifier.
hardware originally used.
Section 4387
Page 33