B R D E L & KJ>ER

Naerum - Denmark

Service Instructions

1/2“ Preamplifier

2 6 1 9

Co ns is tin g o f:

E le c tro n ic S e c tio n 26 19 .1

Po sition o f Co m p onents 2 6 1 9 .2

Parts List 2 6 1 9 .3

C irc u it Diagram 2 6 1 9 .4

How to op en th e P re a m plifie r Typ e 2 6 1 9 , see e xp lo d e d v i e w . (2 6 1 9 . 2 )

Trou b le Sho oting

If th e re ason for a fa u lt is no t an o b viou s on e such as a fa u lty tra n s is to r, bro k en do w n re sis to r e tc . , the n firs t te st the D C -v o lta g e s

and com p a re th e m w ith the v o lta g e s show n in th e ta b les sh ee t 1 in ord er to lo c a liz e th e d e fe c t . Shou ld th is m e th od o f f i n d in g the

fa u l t p rove un su c ce ss ful, th en ch e c k th e in stru m e n t b y a d ip tin g th e m eth od de sc rib e d in the ad jus tm e nt p ro c e d u re . Whe n th e tro u b le

has been fo un d an re m ed ie d , th e v olta g e s and ad ju stm en ts w h ic h are i n flu e n c e d by th e re m e d y must be r e c h e c k e d .

The tole ra n c es sta ted in th e in s tru c tio n s can o n ly be used as a gu id e fo r a d ju s tm e n t an d c o n tro l, b u t a n y de v i a tio n s must not be co i -

re c t e d w ith o u t b e in g sure th a t th e to le ra nc e s o f th e in strum en ts used fo r m ak ing th e a d ju s tm ent a re so sm all as to ha ve no in flu e n c e

on the m easu re m e nts.

The in s tru c tio n s in th is m anu al are giv e n p u re ly as a g u id e to the s e rvic e o f e q u ip m en t w ith m in o r fa u lt s . Some fa u lts , as f. i n s t .

small d e v ia tio n s in to le ra n ce s re q u ire for t h e ir c o rr e c tio n spe c ia l c o n tr o l e qu ip m en t a nd ex te n s iv e e x p e r ie n c e , and in these cases it