Tektronix 434, Instruction Manual

Page: 68 / 222

S E C T I O N 4
M A I N T E N A N C E
4 3 4
Change in fo rm a tio n , i f a n y , a ffe c tin g th is section w it! be fo u n d a t th e rear o f th e m anual.
In tro d u c tio n
T h is se ctio n o f th e m anual co n ta in s m aintenance in fo r ­
m a tio n fo r use in preventive m aintenance, co rre ctive
m aintenance o r tro u b le s h o o tin g o f th e 4 3 4 .
C abinet Removal
Dangerous p o te n tia ls e x is t a t several p o in ts th ro u g h ­
o u t th is in s tru m e n t. When the in s tru m e n t is o p e ra te d
w ith th e covers rem oved, do n o t to u c h exposed
c o n n e c tio n s o r co m p o n e n ts. Some transistors m a y
have elevated cases. D isc o n n e c t p o w e r b e fo re cleaning
the in s tru m e n t o r re p la cin g parts.
T he c a b in e t can be rem oved fro m th e oscilloscope as
fo llo w s :
1. U n w ra p th e p o w e r co rd fro m th e in s tru m e n t fe e t.
2. Loosen th e phillip s-h e a d screw located in each in s tru ­
m e n t fo o t . See Fig. 4-1,
3. Remove th e rear rin g assembly fro m th e rear o f the
in s tru m e n t.
4. S lide th e c a b in e t to th e rear and rem ove th e o s c illo ­
scope.
The R 4 3 2 can be rem oved fro m its c a b in e t in a sim ila r
m anner. T o replace th e in s tru m e n t in its w ra p -a ro u n d
ca b in et, reverse th e rem oval p ro ce d u re . T he p o rta b le w ra p ­
a ro u n d c a b in e t should be installed w ith th e c a rry in g handle
p i v o t p o in ts p o s itio n e d to w a rd th e b o tto m o f the
in s tru m e n t.
P R E V E N T IV E M A IN T E N A N C E
Genera!
P reventive m aintenance consists o f cleaning, visual
in s p e c t i o n , lu b r ic a t io n , etc. Preventive m aintenance
F ig . 4 -1 . R e m o v in g w ra p -a r o u n d c a b in e t.
p e rfo rm e d on a regular basis m a y p re ve n t in s tru m e n t b reak­
d o w n and w ill im p ro ve th e re lia b ility o f th is in s tru m e n t.
The severity o f th e e n v iro n m e n t to w h ic h th e 4 3 4 is
subjected determ ines th e fre q u e n c y o f m aintenance. A
c o n v e n ie n t tim e to p e rfo rm pre ve n tive m aintenance is
preceding re c a lib ra tio n o f th e in s tru m e n t.
Cleaning
General.
The 43 4 should be cleaned as o fte n as opera­
tin g c o n d itio n s req u ire . A c c u m u la tio n o f d ir t in the in s tru ­
m e n t can cause overheating and c o m p o n e n t b re a kd o w n .
D ir t on c o m p o n e n ts acts as an in su la tin g b la n k e t and
prevents e ffic ie n t heat d is s ip a tio n . I t also provides an elec­
tric a l c o n d u c tio n path w h ic h m ay re s u lt in in s tru m e n t
fa ilu re .
The c a b in e t provides p ro te c tio n against d u s t in the
in te rio r o f th e in s tru m e n t. O p e ra tio n w ith o u t th e c a b in e t in
place necessitates m ore fre q u e n t cleaning. T he f r o n t cover
provides d u s t p ro te c tio n f o r the fr o n t panel and th e C R T
face. The f r o n t cover should be in sta lle d fo r storage or
tra n s p o rta tio n .
4-1