HP 3562A Service Manual page 523

MOD E L 3S62A
8-1 0 A7 FLOATING POINT PROCESSOR
The i nformation in this section shou ld be used to isolate fau lty subblocks in the A7 Floating
Point Processor (FPP). A l l proced u res assume the fau lt iso l ation proced u res of Section
V I I have been used to determ i n e w h i c h board has fai l ed, and the c i rc u it descriptions of
Section V I are u nderstood.
Service procedures described in this section are performed with
the protective co vers removed and power applied. Hazardous
voltage and energy available at many points can, if contacted, result
in personal injury.
Do not insert or remove any circuit board in the HP 3562A with
the line po wer turned on. Power transients caused by insertion or
removal may damage the circuit boards.
How to Use This Section
Start
Verify
After-Repai r
TrClubleshooting Hints
1 . After the power-u p tests or reset (A2 51 ), the FPP status LE Ds shou Id be changing rapidly.
I f the L E Ds are off or the FPP does not respond to any self-tests, the prob lem is most
l i kely the sequen cer, the m i crocode memory, the A L U s control logic, or the contro l
PALs. U se signatu re analys i s test #4 to isolate the fai l u re (after perform ing part A).
WARNING
CA UTION
Start tro u b l eshooti ng b y perfo rm ing part A , " I n itial Cond itions Test".
The pri mary troub leshooting method for the FPP is to u se the self-tests
to dete r m i ne w h i c h s u b b l ocks are operating correctly. S ignatu re
analysis is then used to trou b l eshoot i n d ividual s u b b l ocks s u spected
of fail ing.
·
nent locator and sc hematic refer to Section I X . For the
For the compo
l ocation of cables and boards refer to figure 4-1 in Section IV.
U se the osc i l loscope waveforms i n tab l e A7-8 to verify co rrect
ope ration at various test poi nts in the assem bly.
Use tab le A7-9 to determ ine w h i c h adj ustments and tests need to be
done to complete i n strum ent service.
S E RV I C E
8-73