HP 606A Operating And Service Manual page 37

Section IV
Table 4-2
Table 4-2. Troubleshooting Chart (Cont'd)
Model 606A
Measure
Normal Indication
Possible Cause of Malfunction
3. R15 at tank term.
4. V8 ( 6AW8) pin 2
pin 6
pin 9
pin 3
pin 8
pin 7
5. V6 ( 12B4) pin 2, 7
pin 9
6. V3 and 4 ( 6CL6's)
pin 6
pin 3, 8
pin 2, 9
pin 1
7. CR2, anode
D. RF AMPLIFIER (CO
+295 vdc ± 10%
0 to 3.5 vdc as R63 is rotated
+4.1 vdc ( nominal)
+76 vdc ( nominal)
+150 vdc ( nominal)
+54 vdc ( nominal)
0 to + 3.4 vdc as R63 is rotated
-10 to - 25 vdc as R63 is rotated
+110 vdc ( nominal)
+295 vdc ( nominal)
+295 vdc ( nominal)
+100 vdc ( nominal). If this volt-
age is incorrect the rf oscil-
lator is not functioning properly
+112 vdc ( nominal)
6 volt rms ( nominal) with 1 VOLT
output level. Varies 0 to 6 volt
rms as ATTENUATOR VER-
NIER is turned
T'D)
R15 open, C1OC, 11 shorted
R31, 53, 57, 60, 61, 62, 64, 65 and 68
C29, R32, 33, 34, 35, V7, 8
R20, 22, 23, 29, 30, V8
R28, 29, R33, 34, 35, V7
Same as pin 3
C23, 24, 25, CR2, 3, R17, 24, 25, 26, 36, V8
C19, R20, 22, 23, 29, 30, V7 or 8
R10, 38, V3, 4, 6
Shorted C12,14,15, open T3 or contacts on turret
Check C10, 11, 14, 15, 16, R10, 15
Rh, 12 triode section of VI
R13, 14, check voltage on pin 9 V6
Check V3 and 4 plate voltage and output
voltage as given in table 4-4
Symptom
Possible Cause
8. Fuse Fl, ( 0.15 amp) burns out
9. Sharp drop ( hole) in power output level, or a
sharp increase ( peak) in oscillator or ampli-
fier current as frequency dial is tuned
10. R15 ( 100 ohms) burns out
Defective C8, 10ABC, 32, 33, 53 and LI, 4
Foreign material across tuning capacitors: C4, 5,
7, 14, 15 and 18
Defective microswitch S7
Feedback system defective
Check shorting fingers in turret. This prevents next
lower band coil from resonating and absorbing power
Shorted tuned capacitor C14, 15 or 18
Open or shorted CR2, 3
Shorted C23, 24, 25 or S3
If this condition affects one band only, check the turret
contact and coil for that one band. Also check switch
S3 ( on rf deck) for shorts
This condition persists on all bands see table 4-3
E. AUDIO OSCILLATOR
Most troubles can be found easily by measuring the voltages in the circuit as follows:
Set MODULATION SELECTOR to INT. 1000 %
MODULATION AMPLITUDE to 100%
V5 ( 12AT7) pin 1
pin 2
pin 3
pin 6
pin 7
pin 8
Ti leads green
yellow
blue
3.7 volts rms
6.6 volts rms
6.2 volts rms
80 volts rms
3.8 volts rms
1.88 volts rms
20 volts rms
3 volts rms
80 volts rms
+180 vdc ( approximate voltages)
O vdc
+2. 6 vdc
+292 vdc
O vdc
+4. 8 vdc
O vdc ( approximate voltages)
O vdc
+292 vdc
4-6
00170-2