1973 OPEL GT-R ECU

9C-108 1973 OPEL SERVICE MANUAL
11. Grasp instrument cluster and pull straight back,
being careful of wires, etc. See Figure 9C-7.
Figure 9C-7 Removing Instrument Cluster
12. Disconnect radio harness plug and antenna lead-
in cable from back of radio. See Figure
9C-8.
Figure 9C-8 Removing Radio Harness Plug
13. Remove radio knobs from radio.
14. While supporting radio, remove radio shaft re-
taining nuts. Remove radio. See Figure
9C-10.
CAUTlOk Fasteners in Installation are important at-
taching parts in that they could affect the perform-
ance of vital components and systems, and/or could
result in major repair expense. They must be re-
placed with one of the same part number or with an equivalent part, if replacement becomes necessary.
Do not use a replacement part of lesser quality or
substitute design. Torque values must be used
as
specified during reassembly to assure proper
reten;
tion of these parts.
Figure SC-10 Removing Radio Shaft Retaining Nuts
1. Install radio into instrument cluster and secure
with retaining nuts. See Figure
9C-10.
2. Plug radio harness and lead-in cable into radio.
See Figure
9C-8.
3. Install radio knobs and carefully push cluster back
into instrument panel housing, making sure electri-
cal wires, etc., are not pinched. See Figure
9C-7.
4. Install six (6) cluster retaining screws. See Figure
9C-6.
5. Support column assembly and install ground wire
and hex head bolts, torquing to
14 lb.ft.
6. Install NEW tear bolts and tighten until head of
bolt is twisted off.
7. Connect ignition and directional signal wire plugs.
8. Connect speedometer cable.
9. Install flasher unit and hex head screw. See Figure
9c-4.10. Install hex head screw through opening on right
side and install trim plug. See Figure
9C-2.
11. Install trim cover on left side. See Figure 9C-3.

RADIO - OPEL 1900 - MANTA9c- 109
RADIO
OPEL 1900
- MANTA
CONTENTS
Subject
DESCRIPTION AND OPERATION: (Not Applicable)
DIAGNOSIS:
RadioTroubleDiagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAINTENANCE AND ADJUSTMENTS:
Antenna Trimmer Adjustment
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MAJOR REPAIR:
Removal&InstallationRadio. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Removal81InstallationAntenna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SPECIFICATIONS:Page No.
9c-109
9c-110
9c-111
9c-111
DIAGNOSIS
RADIO TROUBLE DIAGNOSISBecause radio problems are most often repaired at
United Delco authorized warranty repair stations,
the tendency for many dealer servicemen is to
remove the set when a problem is reported, without
any preliminary diagnosis. This results in a large
number of radios showing up as “NO TROUBLE
FOUND” units when received by the warranty re-
pair stations. This indicates that the trouble can
often time be corrected without removal of the radio.
The inconvenience to an owner of driving without a
radio while his set is being serviced at a warranty
station can frequently be avoided if the following
quick checks are used to eliminate external radio
system Problems before removing the radio for re-
pair.
Always determine from the owner 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 off or running, with
car stationary or moving, will help to pinpoint theproblem: Never turn on radio with speaker discon-
nected.
Radio Is Inoperative
1. Turn on the radio. The dial should light and a
thump should be heard from the speaker.a. If a thump is heard, go to
Step No. 2 for antenna
check.b. If no thump is heard, check the fuse.
(1) If fuse is bad, replace and try radio again. Race
engine and, if fuse blows again, remove the radio and
speaker assembly for repair by a trained radio techni-
cian.
(2) If fuse is good, check to see that the speaker to
receiver interconnecting cable is connected securely.
If there is still no thump when the radio is turned on,
remove the receiver and speak+ for repair.
2. Check the antenna by substituting with one held
out the car window.
a. If radio is still dead with’substitute antenna,
remove the receiver and speaker for repair.
b. If radio operates near normal with substitute an-
tenna, some part of the car antenna or lead-in is at
fault.
Radio Reception Is Weak1. Check to see if antenna
tri$mer is peaked.
a. Position antenna at a height,of 31 inches.
b. Tune radio to weak station at or near 1400 KHz
on the dial, and turn volume control to maximum.

9C-110 197j 6PEi SERVICE MANUAL
c. Adjust trimmei screw for maximum volume,
d. If antenna trir&ner does not have a definite peak,
check for defective ant&ma by substitution.
2. Check that the speaker connection is plugged in
securely.3. If the radio is still weak, remove the receiver and
speaker assembly for repair.
Radio Is Noisy1. Radio is noisy all the time:
a. Check for defective antenna by striking antenna
with hand. If static is heard while tapping, replace
antenna.
b. If antenna is not defective, remove receiver and
speaker for ripair.
2. Radio is noisy only when jarred:
a. Check antenna as in Step No. 1 above.
b. Check speaker connection. If speaker connection
is not at fault, remove receiver and speaker for re-
pair.
3. Radio is noisy when engine is running:
a. Check noise suppressor by substituting on genera-
tor with known good one.
b. Check to see that antenna is mounted securely,
grounding the antenna base to the fender. The an-
tenna lead-in wire is shielded and the shield should
have good ground corinection at the receiver and the
antenna base.
c. Check for other car wiring passing too close to
radio receiver case.
d. If engine noise is still present, remove receiver and
speaker for repair.
4. Radio is noisy when car equipment is operated,
such as directional lights or brake lights:
Check for defective antenna lead-in wire or loose
antenna mounting, as in Step No. 3b above.
5. Radio is noisy only on dry days when car is mov-
ing:
Wheel and tire static will occur only during dry
weather. To check to see if noise is wheel static or tire
static, drive car until noise is noticed. Touch the
brake. If noise disappears, it is wheel static. If noise
persists, it is tire static. Static may be eliminated in
two ways:a. Wheel static may be eliminated by installation of
static collectors in the front wheels. It is important
to make sure the button on the end of the spiral
collector rides evenly in the spindle. Grease and dirt
can cause poor contact between static collector and
the cap, which would result in wheel static, even with
the collectors installed.
b. Tire static is eliminated by injecting graphite tire
static powder in all
five (5) tires. Either a special gun
or a plastic squeeze bottle can be used to insert pow-
der.MAINTENANCE AND ADJUSTMENTS
ANTENNA TRIMMER ADJUSTMENTAn antenna trimmer adjustment screw is provided
for matching of the antenna coil in the receiver to the
car antenna. This adjustment must always be made
after installation of a receiver or an antenna, or after
repair to these units. This adjustment should also be
performed whenever radio reception is unsatisfac-
tory.1. Position antenna to a height of 31 inches.
2. Tune receiver to a weak station at or near 1400
KHz that can barely be heard with volume turned
fully up.
3. Insert a small-bladed screwdriver in antenna trim-
mer screw and rotate screw until maximum volume
is achieved.
Figure 9C-15 Radio Control Knobs