HP 85108, System Manual

Page: 108 / 136

Procedure 1: Service Adapter T est
If one or more user c hannels app ear faulty , the problem could b e with the source, test set, or
the HP 85102 IF/Detector. The service adapter is a source/test set em ulator. It pro vides the
same 20 MHz signal to the HP 85102 as the test set and source. Th us, it indicates whether or
not the problem is in the HP 85102 IF/Detector.
Equipment
Service adapter (HP part n um b er 85102-60210)
BNC cable
Service Adapter Procedure
1. Connect the HP 85102 service adapter to the HP 85102 rear panel 20 MHz OUT connector
and the J2 IF-DISPLA Y INTER CONNECT connector.
2. Press 4 RECALL 5
NNNNNNNNNNNNNN
MORE
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
FACTORY PRESET 4 MARKER 5 STIMULUS 4 MENU 5
NNNNNNNNNNNNNN
STEP .
3.
Press P ARAMETER 4 MENU 5 and lo ok at the unratio ed p o w er of eac h user c hannel (User1
through User4). The traces should b e at lines, and all four c hannels should lo ok similar.
Conclusions
If all of the c hannels lo ok go o d (with the service adapter), and all lo ok ed bad in the unratio ed
p o w er test, the HP 85101 and 85102 are w orking. The problem is likely source related. Refer
to y our source troublesho oting man ual for further information.
If all four User c hannels lo ok bad (with the service adapter), susp ect the 20 MHz signal
from the A6 clo c k b oard assem bly in the HP 85102.
Single c hannel problems suggest the IF Mixer b oard corresp onding to the User function
(c hannel a1, b1, a2, or b2) is faulty . Refer to Figure 6-5 .
Multiple c hannel problems indicate the problem is most likely in the HP 85102 circuitry
after the IF Mixer b oards.
Procedure 2: A2 Pulse IF Mux T est IF P ath Check
Prerequisite for using this c hec k: Only the b1 or the b2 pulsed-RF IF signal path lo oks bad.
In the t w o pro cedures b elow, alw a ys return an y mov ed cables to their original connections
b efore pro ceeding to the next step.
If the connections/setup correct the problem, carry out the instructions in the conclusion
column. If the problem isn't corrected, go on to the next step.
6-16 System Service and Troubleshooting