Service manual

7. All Equalization Controls in 0 (flat) setting.
8. All Volume Controls set to maximum (12).
9. Tone oscillator circuit measurements on Main
Board (Bd.
3) made with TONE OSC Switch on
(out).
10.
LIMITER Switch in IN position.
DC VOLTAGE MEASUREMENTS
The numbers within elliptical symbols a on the
circuit diagram denote the dc voltages at that point under
the following conditions:
1. Voltages measured with respect to chassis unless
otherwise indicated.
2.
Line voltage:
120V, 50/60 Hz (SR109)
120V or 240V, 50/60 Hz (SR109-2E)
3. No input signal applied.
4.. Dc voltage measurements may vary &20% from
values shown.
5. Measurements made with VTVM of 11 megohms or
greater input impedance.
6. Tone oscillator circuit measurements on Main Board
(Bd.
3) made with TONE OSC Switch on.
RESISTANCE MEASUREMENTS
With the ac line cord disconnected from the ac source
and the POWER OFF Switch in the OFF position, the
following ohmmeter measurements may be made:
1. Transformers may be checked for continuity of each
winding.
2. To test transistors and diodes, see Page 17.
3. To check LEDs, see Page 17.
4. To check opto-isolator, see Page 17.
81227-11-1
FIGURE 24. SR109-2E POWER SUPPLY CIRCUIT DIAGRAM