Aeroflex ATC-1400A-2 - Page 44

MAI NTENANCE MANUAL
ATC-1400A-2
2-2-2
Page 4 4
Subj e c t to E x p o rt Con t r o l, s e e C o ver P a g e fo r d e tail s . F e b 2/ 0 9
STEP PROCEDURE
7. Set Os c i l l osco p e to A l t e r nat e . V e r i f y l e a d ing e d g e of s u ppr e s s or p u l s e i s
app r o x imate l y . 8 µs with l e a ding e d ge o f X PDR P
3
pul s e .
8. S e t PRF/SQ T R ON/ OF F S w i tch t o O F F , TO /TAC/ T D S w i t ch to T D ,
FREQ/FUNCT I ON S E L E C T Thumbwhe e l s to 1 0 9 0 MHz Y an d S E LF-INTE R R/ OF F
Switc h t o SELF-INTER R .
9. Ver i f y lea d i n g ed g e of s u p p res s o r pu l s e occ u r s ap p r o x imate l y 3.5 µs bef o r e P
1
of r a n g e re p l y pu l s e .
10. Ve r i f y ampli t u d e of g e n erat o r pul s e s ar e a p pro x i matel y 0 . 5 V
P - P
int o 5 0 Ω Load .
11. Set T O / T A C / TD Switc h t o TO , P R F / S Q T R ON/OFF Switc h t o O N a nd
FREQ/FUNCT I ON S E L E C T Thumbwhe e l s to 10 9 0 X P DR.
12. Ve r i f y le a d i n g e d g e of P
1
occ u r s ap p r o ximat e l y 20 µs a f t e r b e g i n nin g o f
Oscil l o s co p e t ra c e .
13. Set T O / T A C / TD Switc h t o TD an d v e rif y l eadi n g edg e o f P
3
occ u r s at b e g inn i n g
of Osc i l los c o p e t r a c e.
14. Set PRF / S Q T R O N / O F F S witc h t o OFF and F R E Q / F U N C T I ON SELECT
Thu mbwh e e l s t o 1 090 MHz X .
15. Ver i f y P
1
of r a n ge r e p l y o c c u rs a p p r oxi ma t e l y 3 . 5 µs afte r b egi n n i n g o f
Oscil l o s co p e t ra c e .
16. Set T O / T A C / TD Switc h t o TAC, TA C A N O N / O F F S witch t o O N a n d SEL F -
INTERR / OF F S w i tch to OF F .
NOTE: Osc i l los c o p e s y n cs o n m a i n b u r s t.
17. Ve r i f y p u l s e sp a c i ng b e t w e en l e a d i n g edge o f fir s t p uls e t o le a d i ng e d g e of
sec o n d pu l s e is 1 2 µs and s p aci n g bet w e e n le a d i ng e d g e of s e con d p uls e t o
lead i n g ed g e o f t h i r d pu l s e is 1 8 µs.
18. Con n e c t Fr e q u enc y C o u nte r t o J9 0 4 , pin 2 1 B. F o r e xtra c l a rity , r e fer t o
Motherb o a r d PC B o a r d Ass e m b l y , par t o f Fl o o r Asse mb l y ( 2-2- 5 , F igur e 8 8 ).
19. Set FR E Q/ F U N C T I ON SELEC T T h u m b w h eels t o M H z Y, IN/ OU T S w i t ch to O UT ,
RANGE/VEL/ A C C E L T humbwhee l s to 100 0 K T S and D I S P L A Y SEL E C T C o n t rol
to RANGE.
20. Pres s LOAD V E L P u shb u t t o n Swit c h . Ver i f y 2 7.7 7 7 Hz (±0. 0 1 4 Hz) i s dis p l a yed
on F r e q uen c y C o unt e r .
21. Set POW E R S w i t ch t o O F F .
22. If n e e ded , e x chan g e plac e s with P C B o ard A s s emblie s t o move D ME R a n g e PC
Boar d A ssembl y t o to p s l ot i n C a rd Ca g e Asse mb l y
23. Set POW E R S w i t ch t o O N .
24. Remove F r eque n c y Coun t e r fro m J 9 0 4 , pi n 2 1B a n d c onn e c t to U5 1 5 , Pin 5
(DME Range P C B o a rd A s s e m b l y ) (2 - 2 - 5 , Fi g u r e 78).
25. Pr e s s CLEAR RNG P u s h b utt o n S witch t o clea r a ll p r e v i ous e n t ered r a nge,
vel o c i ty a n d acc e l e rat i o n da t a .