AMOM' W-aw~


 -1:- '
 You say you're tackling a mainte-
nance problem in a radio set?
 Fine ... but don't double your trou-
ble by goofing up your test set, like the
AN/GRM-55( ), by pushing the MX-
4622 test prod into unexplored test
points.
 Like, before making tests in the A-1
module in a RT-505/PRC-25 receiver-
transmitter, make sure J2 and J3 jacks
have correct DC polarities 100
volts for J2 and -35 volts for J3 when
checked on 100-volt range of the
AN/URM-105 multimeter.
 'Cause, if there's a whopping big dif-
ference in these voltages or in the polar-
ity, your GRM-55's probe diodes will


 be damaged. Small voltage variations
 due to input power may exist, but polar-
 ities must be correct.
 So, if this voltage polarity differs or
 if the voltages are much higher re-
 place the A-1 module with a good one.
 And, see to it the function switch is
 in C position before touching the test
 set's probe to the RT's A-i, A-9, A-11,
 A-16 or A-17 module.
 High voltage applied while the
 GRM-55 switch is set on A or B position
 could damage the test probe diodes, and
 knock the whole tester's calibration out
 of kelter.
 If you wind up having to replace the
 prod, return the test set to higher eche-
 lon for repair.
45


TIPS FOR
"EST PROD