Astor P3B Service Manual

Radio C or p or ation P ty. Ltd. p 3b - i

— ^ div is ion o f e l e c t r o n i c indus tries LTD. Fiie; Receivers

L U l v As t o r H ou se, 161-173 Stu rt Street, South Melb ourne,

Battery

Date: 18-10 -62

SERVICE DATA

rage: 1

MODEL P 3 B

POR TABLE

7 TRANS ISTOR SUPERHE T ERODYNE

BROADCAST BAND RECEIVER

NO T E : R e c ei v e r c h a s s is does n o t h a v e to be r e m o v ed fr o m c ab i n et f o r a l ig n m e n t pu rp o s e s .

1. A C C ES S T O C HA S S I S .

Op e n the ca bin e t b y u n s c r ew in g the s in g l e scr e w l o c a t ed on the re a r, n e a r b a s e o f
ca binet .

2. CH A S SIS S E R I A L N U M B E R.

4

L o c a t e d o n m e ta l ch a s sis a b ove sp e a k er. Vis i b le when ca bin e t r e a r fla p is opened .

3. R E M O V A L O F C H A SSI S F R O M C A B I N E T .
Open cab inet , de t a i l e d in p a ra g r a p h 1.
R e m o ve k nob s , pu l l s t ra i g h t o f f s ha f t s .
Re m ove tw o s cr e w s f rom c h ass is , l o c a t e d o n e at ea c h en d d i r e c tly b e lo w the e x t r e m e

o ute r d i a l c o r d p u ll e ys .
R e m o v e t he s c r e w f r o m bas e o f c a b in e t a l so th e e x t e r n al a e ria l and e a rth sc r e w s .
Dis e n g a g e e x t e r n a l a e r i a l an d e ar t h sp eed n u t s f r om m o u n t b ra ck e ts the n l ift ch as s is

out o f ca b i n e t .

Information con tained herein must not he reproduced without prior written permission from

Radio Corporat ion Pty. Ltd.

LONG
WIRE

EARTH AERIAL

2N 4I2

2N4IO

2N 4IO

2 N 4 0 6

2N 4 0 6

OC 74

NUM BER S A SSIGNED TO TERMINALS OF COILS AND TRA NSF ORM ERS
ARE TO FACILITATE CIRCUIT TRACING OR COMPONENT REPLACEMENT
AND MAY NOT BE FOUND ON THE UNIT.

ALL VOLTAGES MEASU RED BETWEEN POINTS INDICATED
AND COMMON P OSITIVE WITH A D.C. VACUUM TUBE

\2s

DRIVER

TRA NS FO R ME R

ISSUE 2 — CIRCUIT NO.21. ADDED.- CIRCUIT NO.49. WAS 220 .- CIRCUIT NO.23. WAS *01.

VOLTMETER. (NO S IGNA L)
CURRENTS INDICA TED ARE MEASURED WITH AVO MULTIMETER

MODEL Θ. (NO SIGNA L)

PR E C A U T IO N S WH EN TE S T IN G TRA N S IS TO R RE C E I V E R S

A. A t r a nsi s t o r is e x t r e m e l y s e n s i t iv e to he a t . If a s o ld e r i n g i ro n is to be u s ed c l o s e

to a t r a n s i s t o r m o v e th e t r a n si s t o r o r p l ac e n o n - c o n d u c ti v e m a t e r i a l b e t w e e n the
ir o n a nd t r a n s i s t o r .

Wh en m a k i n g s o l d e re d c o nn e c ti o ns to the l e ad s of t he t r a n s i s t o r s ho ld the l ea d w hi ch
is be i ng s ol d e r e d b e tw e e n th e h e a t s o u r c e an d t r a n s i s t o r b od y w i th p l i e rs ; e x c e s s
h e a t w il l be d i s s ip a t e d a w ay i nto the p l i e r s .

Us e a so l d e r in g i r o n w h ic h s u p p li e s j u s t the r e qu i r e m e n t of he a t f o r s a t i s f a c t o ry
s o ld e r i n g of c o n n e ct io n s .

B. W h en ch e c ki n g c o m p o n en t s, c u t t he lon g p ig t ai l of th e c o m po n e n t in p r e f e r en c e to

u n so l d e r i n g f ro m t he c i r c u i t b o a r d . C o m p on e n ts c h e c k e d i n thi s w a y m a y be
r e t u r n e d int o the c i r c ui t b y p r e s s i n g the en ds of th e p ig ta i l t o g e th e r th en s o l d er .
F a u l t y co mp o n e n ts s h ou ld be r e m o v e d f r o m th e c i r c u i t b o a r d by c ut ti ng th r ou g h th e
bo dy of the c o m p o n e n t le a vi n g two s ho r t s tu b s of w i r e p r o tr u d i n g ( ap p ro x . 1 /8 1')
ab o ve the c i r c u it b o a r d . The p i gt a il le a d s of the n e w c o m p o n e n t a r e to b e s o l d e r e d
to th es e s t u b s .

C. A c o n ti nu i ty m et er m u s t n o t be a p pl i ed to the r e c e i v e r w i ri n g w i th th e t r a n s i s t o r in

c i rc u i t . A t r a n s i s t o r m u s t n ot b e c h e c ke d f o r co n ti n u it y w it h a n o h m m e t e r as the
ap p l ie d v o lt ag e an d r e s u l t a n t e x ce s s c ur r e n t fl ow m a y r e s u l t in p e r m an e n t d a m a g e
to th e t r a n s i s t o r . A v ol t m e t e r o f a t l ea s t 20, 000 o h m s / vo l t o r a h i gh i m p e d a n c e
va c u u m t ub e t ype v o l t m e t e r i s a s a fe m e a n s of me a su r i n g c i r c u it v o lt a ge .

D. A s c re w d r i v e r o r s i m i l a r in s t ru m e n t m us t n o t b e u se d to s ho r t c o m p o n e nt s t o g e t he r

o r to t he c o m m o n p o si ti v e . Th e u s e of thi s m e th o d of ch e ck i ng fo r th e e x i st a n c e of
vo lt a ge o r s i gn a l c li c k s m a y r e s u lt in p e r m a n e n t d a m a g e to the t r an s i s t o r s an d
c om p o n en t s .

ST O R A G E W H EN O U T O F US E

It is no t a d v is a b l e to l e av e an e x h au s t ed b a t t e r y in the r e c e i v e r . If the r e c e i v e r is s t o r e d
aw a y o r no t r e q u i r e d f or lon g p e ri o d s, e v e n par t l y - u s ed b a t t e r i e s m u s t b e r e m o ve d an d
s to r e d in a d r y c o ol pl ac e . T h is is a p r e c a u t i o n a r y m e a s u r e a g a i n s t t he s w e ll in g a nd
c o rr o d i n g a c t io n of w o r n - o u t b at t e r i e s , w h i ch a p pl ie s to al l b a t t e r y o p e r a t e d d ev i c es , s u ch
as t o rc h e s , e tc .

CL E A N IN G O F C A B I N ET

Do no t p o li s h t he p l a st i c or m e tal s e c ti o n s w i th an a b r a si v e m a t e r i a l, m ot o r c a r p o li sh ,
bo o t po l is h o r s i m i l ar h o u se h o ld c le a ni n g fl ui ds as p e r m a nen t d a m a g e ma y r e s u l t to the
fi n is h of th e c a bi n et . T o r e s t o r e the l u s t r e of the c a b in e t w ip e w ith a s o ft c lo th d am p en e d

w ith w a t e r a nd li g ht ly p o li sh w i th a n e u t r a l w ax .

S U P P O R T S T RAP - RE C E I VER TO CA R S E AT

A s t r a p a nd s tr i p a s s y , is su p pl ie d, to p r e v e n t the r e c ei v e r fr o m t ipp in g w h i l s t in u se on a

c a r se a t . L oo p t he s t r a p to the h a nd le o f r e c e i v e r . Fa s h i o n the r ig i d s t r i p s e c t io n to

for m a h oo k o v e r th e b a c k s u p p o r t s e c t i o n of se a t .