Troubleshooting Chart - Eico HF 12 Instruction Manual

SYMPTOM
Amplifier causes power line fuse
to blow. Power Iine fuse blows a-
gain with V6 out of socket.
Amplifier causes power line fuse
to blow. Power line fuse does not
blow again with V6 out of socket.
Any or all tube filaments not lit.
DC voltage at V6 cathode (pin 9)
is incorrect as specified below.
a) No voltage
b) High voltage.
c) Low voltage.
Excessive hum on mag. phono
or tope head.
Excessive noise on mag.phono
and tape head
Sustained oscillations.
Sustained microphonics on mag.
phono 'and tape head.
Hum on all inputs
TROUBLE-SHOOTING CHART
CAUS E
Line cord, J6, primary or high voltage
secondary windings of T2 shorted internally
or externally (wiring).
V6, C17, V4, V5, or T1 primary shorted
internally or externally.
Open lead from 6.3V winding of T2.
6.3V winding of T2 open.
Defective V6
C17 shorted internally or externally.
Connection from C17 to pin 9 of V6 broken.
Connection
to
center tap of h. v , secondary
winding of T2 open.
Output tubes V4 & V5 over-biased or not
drawing current.
Excessive current drain in amplifier.
Defective V6
Vl defective
Fil. leads dressed too close to grid lead.
Tube shield not making electrical contact
to base or base not making electrical con-
tact to chassis.
Shielding and grounding of wiring to input
jacks not exoctly as instructed and shown
in drawings.
V1 socket and contacts dirty.
poor dress of output transformer T1 leads
Vl defective.
V2 defective, not properly shielded, or
dirty sockets and contacts.
Dress of power transformer 12 leads.
7
REM ED Y
Replace or repair.
Replace or repair.
Repair
Replace
Replace
Replace or repair.
Repair
Repair
See trouble-shooting typical tube
stage.
See trouble-shooting typical tube
stage.
Replace
Replace
Dress fi I. leads away from grid lead.
Check and correct
Correct
Clean throughly with carbon
tetrachloride.
Dress all input leads and T1 leads
away. from each other. Keep T1
leads away from input lacks.
Replace
Replace, correct, or clean.
Correct