Pontiac Fiero 1988 Service Manual page 1245

9A-2 RADIO SYSTEMS AND ANTENNAS
1. Turn ignition to the accessory position and turn
radio on.
2. On AM-FM radios, if the radio is dead on FM
but the AM plays normally, the radio should be
removed for repair. (The reverse of this condition
does not necessarily call for radio removal).
3. On combination radio/tape units, if the radio
operates properly but the tape player does not,
the unit should be removed for repair. (The
reverse of this condition does not necessarily call
for radio/tape removal.)
Always determine the exact nature of the radio
problem as an aid to diagnosis. Knowing whether
the condition is intermittent or constant, whether
it occurs with engine offer running, and whether
it occurs with car parked or moving will help to
pinpoint the problem.
Radio diagnostic information is in Section 8A.
FIXED
A N T E N N A
Testing For Good Ground of Antenna Mounting
and Connections
Poor grounding of the power antenna, either at
the antenna mounting or at any other connection in the
antenna/lead-in system, can result in seriously reduced
radio performance. A poor ground can be a reason for
excess ignition noise in AM reception, or erratic audio.
To check for a poor ground of the antenna,
perform the following:
1. Fully lower antenna.
2. Disconnect antenna motor electrical connector.
3. Remove escutcheon from fender.
4. Attach alligator clip to upper end of antenna to
act as antenna. Leave other end of clip
unattached.
5. Tune radio for weak AM station or signal which
is dependent on clip, i.e., clip attached, station is
present; clip removed, no station.
6. Remove clip.
7. Ground upper end of antenna to fender
(preferably with knife blade, very short jumper
wire, etc.).
8. If radio station is not received, then the antenna
grounds are good. If the station is still present or
stronger, a poor ground or no ground connection
is present in the system.
Possible ground loss points are:
• Antenna upper mounting (screws loose,
paint overspray, etc.)
J Coaxial connector at antenna not tight or
corroded. (Remove to inspect inside the
connector for corrosion.)
• Coaxial connector at radio not tight or
corroded.
• Quick connect connector corroded.
Checking Antennas
Unplug antenna lead-in at back of radio and plug
a test antenna into radio. Make sure test antenna base
is grounded to the car chassis and keep hands off of the
antenna. Check radio reception in an area away from
C A S S E T T E T A P E P L A Y E R DIAGNOSIS
TAPE ONLY
TAPE DEAD
TAPE WEAK
CHECK PLAYER FOR
OBSTRUCTION BEHIND
DOOR
1. INSPECT & CLEAN
CAPSTAN AND HEAD
2. TRY A KNOWN GOOD
TAPE CARTRIDGE
I
NO OBSTRUCTION
I
OBSTRUCTION
TRY A KNOWN
GOOD TAPE
CARTRIDGE
NOT OK
REMOVE
OBSTRUCTION
REMOVE RADIO
FOR REPAIR
OK
IT-
ADVISE CUSTOMER
TAPE IS WORN OR
DEFECTIVE
DEAD WORKS
REMOVE RADIO UNIT
FOR REPAIR
ADVISE CUSTOMER
TAPE IS WORN OR
DEFECTIVE
520253-9
Fig. 1 Tape Player Diagnosis