The Marantz Model 2220B is a classic stereo receiver from the 1970s featuring 20 watts per channel RMS power, built-in AM/FM tuner, phono input for turntables, tape monitor circuits, loudness control, and the iconic Marantz blue dial display. This service manual covers technical specifications, circuit diagrams, alignment procedures, troubleshooting, and maintenance guidelines for qualified service technicians.
Complete electrical and performance specifications for the Marantz 2220B stereo receiver.
| Parameter | Specification |
|---|---|
| Power Output | 20 watts per channel RMS (8 ohms, 20Hz-20kHz) |
| Total Harmonic Distortion | 0.3% at rated output |
| Frequency Response | 10Hz-50kHz (+1, -3dB) |
| Input Sensitivity | Phono: 2.5mV; Aux: 250mV |
| Signal-to-Noise Ratio | Phono: 70dB; Aux: 85dB |
| Tuning Range | FM: 88-108MHz; AM: 530-1620kHz |
| Capture Ratio | 2.0dB |
| Selectivity | 60dB |
| Image Rejection | 60dB |
| Power Requirements | 120V AC, 60Hz, 85 watts |
Functional block diagram showing signal flow through the receiver sections.
WARNING! High voltages present in power supply section. Exercise extreme caution when servicing.
Detailed explanation of major circuit sections and their operation.
CAUTION! Always use isolation transformer when testing live circuits.
Complete listing of components with manufacturer part numbers and values.
Transistors: 2SC458 (Q101-Q104), 2SC945 (Q201-Q204), 2SD313 (Q401,Q402)
Diodes: 1S1555 (D001-D010), 1S2473 (D101-D110)
Integrated Circuits: HA1156 (IC001), TA7136P (IC201)
Capacitors: Electrolytic: 2200µF/35V (C701,C702), Film: 0.47µF/50V (C101-C110)
Resistors: Carbon film 1/4W and 1/2W types throughout
Complete schematic diagrams for all circuit boards and sections.
Tip: Refer to component layout diagrams when replacing parts.
Physical layout diagrams showing component placement and trace routing.
WARNING! Observe polarity when replacing electrolytic capacitors.
DC voltage measurements at key test points under normal operating conditions.
| Test Point | Voltage (DC) | Notes |
|---|---|---|
| TP701 (+B) | +35V | Main positive supply |
| TP702 (-B) | -35V | Main negative supply |
| TP703 (+24V) | +24V | Regulated supply |
| TP704 (+15V) | +15V | Tuner supply |
| TP401 (Output L) | 0V ±50mV | Left channel output |
| TP402 (Output R) | 0V ±50mV | Right channel output |
Systematic approach to diagnosing and repairing common problems.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| No power | Fuse blown, power switch | Check F701 (2A), replace if blown; test power switch |
| No audio output | Protection circuit, amplifier | Check relay operation; test output transistors |
| Distorted sound | Bias current, capacitors | Adjust bias; replace leaky coupling capacitors |
| No FM reception | Tuner section, power | Check +15V supply to tuner; test RF/IF stages |
| Hum in audio | Grounding, filter caps | Check ground connections; replace C701,C702 |
Reset: None required - analog circuitry
Important notes and observations from field service experience.
Common failure points: 2SC458 transistors in phono stage, power supply capacitors, selector switches causing crackling, output transistors shorting due to age.
CAUTION! Always discharge large capacitors before working on power supply.
FCC Part 15: Class B digital device; complies with interference limits. Copyright © 1976 Marantz Company, Inc. All rights reserved. For technical support, contact authorized Marantz service centers. Original equipment specifications subject to change without notice.