Version: 13. September 2004
21
either by the word log or the letter B (2,2k B or 2k2B). Solder 3 pieces of
wire, each 15 cm long onto the potentiometer. To prevent hum, twist the
three wires.
Test Section 6
1. Visual inspection
(see Section 1)
2. Widerstandstest
(see Section 1)
[ ] put pin 29 to +10 Volt (see Section 5)
[ ] Bridge pin 47 to pin 18
[ ] Bridge pin 20 to ground
[ ] Connect head phones to pin 44 and ground
[ ] Connect potentiometer arm to pin 33, ends to pins 26 and 34
[ ] Put potentiometer in center position
[ ] Apply power as in Section 1 test.
3. Smoke test
(see Section 1)
current should be abt 85 mA
4. Functional test
After switching on, a definite noise should be audible in the phones. If the
pin 20 to ground bridge is removed, the noise should decrease substantially
(instead of this bridge you can later
on install an S meter). Without the
bridge or S meter, the
A244/TCA3440 doesn’t work correctly.
With the bridge in place, touch the
point marked input test (Einspeise-
punkt) in the drawing with a screw
driver. Now you should hear weak BC
signals. If you hear some irregular up
and down in the hiss, dont take care
this is because the input of the high gain IF amplifier is open in this
moment.
If all tests were successful, remove the bridges and proceed to section 7.
Einspeisepunkt