HP 3562A Service Manual page 505

MOD E L 3562A
8-9
AS, A6
Digital Filter and Digital Filter Controller
The information in this section shou ld be u sed to isolate fau lty subb locks i n the AS Digital
Fi l ter and the A6 D igital Fi lter Contro l l er. These two boards, referred to as the D igital
Fi lter Assembly (D FA), work together to fi lter the i n p u t s ig n a l before i t is stored i n G lobal
RAM. All p roced u res assume the Fau lt I solation porcedu res of Section V I I have been us­
ed to determ i n e w h i c h board has f a i l ed and the C i rcu it Descriptions of Section V I are
u nd erstood .
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 a n y circuit board in the HP 3562A with
the line power turned on. Power transients caused by insertion or
removal may damage the circuit boards.
How to Use This Section
Start
Prolcedure
Reference
Afh�r-Repai r
Troubleshooting Hints
1 . J u mpers are provided to cross-con nect the i ncom ing serial bit streams from the ADC
boards. Refer to the AS schematic in Section IX. When AS J2 and AS J3 are p l aced
in the i r test pos ition (T), i n put d ata from ADC1 is routed to the c h a n n e l two d igital
fi lter block and i n put data from ADC2 is routed to the channel one d i g ital fi lter block.
These j u m pers may be used to aid in fau lt isolation.
2 . If a channel i s conti nuously overloadi ng, start troubleshooting the Overload Detect
s u b b l ock on the AS assemb ly.
WA RNING
CA UTION
Beg i n with trou b l eshooti ng h i nt -1 . I f the fai l u re is determ i ned to be
on the D FA, perform the DFA d i agnostic self-tests whi l e keeping track
of the su bblocks that are verified and the s i g n a l s that are fa i l i ng.
Check the c l ocks and s i g n a l s l isted i n the 'Signal Verification'
paragraph. After determ i n ing the possi b l e defective s u bb locks, use
s ignatu re a n a lysis to iso late the fai l u re.
Refer to Section I X for the com ponent locator and sc hematic. Refer
to f i g u re 4-1 in Section IV for the location of cables and boards.
U se tab le A5-8 to determ ine w h i c h adj ustments and tests need to be
done to com plete i nstru ment service.
S E RV I C E
8-55