Vector 4 - Page 189

VECTOR GRAPHIC, INC.
SYMPTOM
S el aud mant g o Doy gy el ol el e st mad aa el g e aad e o Al o oy e L oy e g o St ann . anal Sl M e o e g aea o
CHECK
NORMAL
St gaeel . aanr' Bike e 23 oot s SRt Sral, e A Sl sl ol md . sl st e S,
ABNORMAL
a) U122-9, U122-25
Baud rate (1)
et s S e ke St Sk, M. Slo S, iy Sulls ke AL vk BrLe S3 Py e Eubs
Check U97 for proper
for T2 Go to 8b. operation. If abnormal,
replace U937,
b) U122-19 TxD Active Check U122-10 and
Sk g At menf g o a mad al al ad aat mf e el el ol o ondr e, . o gt gt gl g . e . et el ma et e e s e g anf . aatf aaat oag
e Gt S, St . gt i, At . et el sl o et sl el el ok ol el e ot el
U122-11. If normal,
replace U122, If
abnormal, check US55,
U84, U122-10 and 11,
and U106 for correct
operation.
St Sl S GEAC. St e e aaf aa g e P L e g ol o o
¢) Check for stuek
inputs preventing
operation of 8251.
e Ss Sl s Snte nalhs Anate Bt Bauile sl ml sl ouul Ll et ek Mo Sl . o oy e et
Sl e Ay s aal . 2nah, Gl ot an g aat. e e o aaad ot Aaal amad . al et st aant
P e C e g g o g e et ang sl el gt anal aauly sl maal aeg S gt maa
9. DCE functioning
correctly:
e . Bl el e el el gl e o e e et gl o e g )
9.12) U121-9, U121-25
for T1
Baud
rate (1)
Go to 9.1b.
S e ol el ol o o al o s ot et ol el g s f e o s e
g s . e g Ly el sl aad el ol it el el . e e s oot ki ol
Check U97 for
proper operation.
abnormal, replace.
9.1b) U121-11 CS
U121-10 WR
el Gl aat s g oy el et o o ang et e o . and anl e aag o oag . ad g
Active low
Active low
(Both must be low
for 8251 to be
selected).
Refer to 9.lc.
e s . ) o ol g o aag aar anel an' mac s et ol ot o sl g g et
o A et . el o . gl b o . . e s aa o A% sl
Isolate to faulty
component — U353,
U106, U84,
Sue Ml S, AR B e el el Ll o e . g e ol e g gy
le) Check inputs and
outputs to ensure that
none are stuck.
ot e G A . . el o ol ) et g gl mul aule Sl Sl Suk. aulls Svs Sl sk ank,
St e et aal g sl st ang ngf angf sngl el ot ol e . s ek gt el auet. ek, ats sk
s e s B Gl s B A S an e e g k. g o ey el o
aml, aul, ol aet’ ad st ang ang sl o o ol el aag sk s, ek, Gl Suk ke SNl sl
9.2 No Rx (asyn-
chronous)
AR . S ol . . e o ol and e ot et st el st audt . el aeaf s
9.2a) U121-11 CS
U121-13 RD
Active low
Active low
(Both must be low
for 8251 to be
selected).
Refer to 9.1c.
Al A et e sl o e e al . sl ang aad . el aaeC. and ) anal el snats and' anel aael
ol . ana . sl amal. s B s At SeuCe dant, St g et aanf sl ant oot ' el sl et an’ ol pa
Isolate to faulty
component — U353,
U84, Ull4.
Sl Bl gaak. . et aaat mal oy e ul . e Sl sutfe ke &%
(1) Baud rate is software—selectable.
V 3-6
7200-0001
09-01-82