The service manual for the Rohde & Schwarz SRM BN 4085 RC Generator provides detailed instructions on setting up the device, including adjusting the mains voltage and turning it on, as well as operating it by setting the desired frequency and regulating the output voltage. It also covers troubleshooting aspects such as ensuring proper connections and understanding the output characteristics, including the harmonic distortion and frequency response for both outputs.
Manual Overview
The Rohde & Schwarz SRM BN 4085 RC Generator service manual provides detailed instructions for operation, troubleshooting, and maintenance of the device. The generator operates within a frequency range of 30 Hz to 300 kHz, divided into four bands, and features two outputs with different impedance levels. Troubleshooting involves checking the power supply settings and ensuring the correct voltage is selected using the voltage selector switch. Error diagnostics are not explicitly detailed, but maintaining proper voltage and load conditions is crucial for optimal performance. Calibration involves setting the desired frequency using the control knob and range switch, with the output voltage adjustable via a separate control. The manual emphasizes the importance of using appropriate fuses for different voltage settings to prevent damage. The device’s circuit comprises an oscillator, power amplifier, and power supply sections, with a Wien-Bridge network determining the frequency. Proper grounding and connection of output cables are essential for accurate signal transmission.
Quick Issues Covered
- Adjust network voltage for 115, 125, 220, or 235 V.
- Frequency setting via knob and range switch adjustments.
- Output voltage regulation for both outputs using right knob.
Overview
The product is the RC-Generator Type SRM BN 4085 by Rohde & Schwarz. The manual covers its properties, applications, setup, operation, and construction. The RC-Generator is designed for audio and carrier frequency technicians, offering a wide frequency range from 30 Hz to 300 kHz, divided into four sections. It features low distortion and good frequency stability, making it suitable for modulation voltage sources and frequency measurement devices. The manual includes instructions on adjusting network voltage, frequency settings, and output voltage regulation. The device has two outputs with specific characteristics and is constructed with an oscillation part, power amplifier, and power supply.
Specifications
- Frequenzbereich: 30 Hz…300kHz
- unterteilt in 4 Bereiche: 30…300 Hz/3/30/300 kHz
- Fehlergrenzen: +2%
- Frequenzkonstanz, kurzzeitig: ±0,1%
- Skalenverlauf: etwa logarithmisch
- Zwei Ausgänge: Je eine 13-mm-Buchse FMU 90100 mit Anschlussmöglichkeit für Bananenstecker
- Ausgangsquellwiderstand Ausgang I: 600 Ω ±2%
- Ausgangsquellwiderstand Ausgang II: etwa 100 Ω
- Leerlauf-Ausgangsspannung Ausgang I: max. 1V
- Leerlauf-Ausgangsspannung Ausgang II: max. 30V
- Ausgangsleistung am Ausgang II bei Ro= 3kΩ: 0,3 W
- Ausgangsleistung am Ausgang II bei RA = 600Ω: 0,5 W, k < 10%
- Klirrfaktor Ausgang I: < 1% für f < 100 kHz, <2% für f > 100 kHz
- Klirrfaktor Ausgang II: < 1% für f < 100 kHz (bei < 30 V und Rg = 3 kΩ), < 2% für f > 100 kHz
- Frequenzgang der Ausgangsspannung Ausgang I: <±5%
- Frequenzgang der Ausgangsspannung Ausgang II: <±5% bei Ra > 3kΩ
- Brummspannung: < 0,1% bezogen auf max. Spannung
- Netzanschluss: 115/125/220/235 V ± 10%
- Bestückung: Röhre EF 40, 2 Röhren EL 41, 1 Röhre EZ 80, 1 Regel-Glühlampe, 1 Zwergglimmlampe RL 210, 1 Schmelzeinsatz M0,6 C DIN 41571 (für 220 und 235V Netzspannung), 1 Schmelzeinsatz M0,25 C DIN 41571
- Abmessungen: 470x275x260 mm (R&S-Normkasten, Größe 46)
- Gewicht: 8 kg
Controls & Indicators
Refer to the PDF for details.
Installation / Setup
The setup of the RC-Generator Type SRM BN 4085 involves adjusting the device to the appropriate mains voltage, which is preset to 220V at the factory. To change to other voltages (115, 125, or 235 V), the device must be removed from its casing by loosening screws on the front panel edges. The appropriate contact spring pair on the voltage selector must be bridged with a suitable fuse. For 235V, the 600-mA fuse used for 220V is suitable, while a 1.25-A fuse is required for 115V and 125V. After reassembly, the device is connected to the mains and switched on using the toggle switch above the mains cable entry. A small glow lamp above the switch indicates the power state. The generator is ready for operation after a warm-up period of about one minute, with optimal frequency stability achieved after approximately 15 minutes. The mains voltage can deviate by ±10% from the nominal value without significantly affecting the generator’s function, but prolonged over or under-voltage should be avoided to extend tube life. For under-voltage situations, using a transformer is recommended.
Operation
The manual provides detailed steps for the basic usage and operation of the RC-Generator Type SRM BN 4085.
1. Setting the Mains Voltage and Switching On: The device is initially set to 220V. To adjust it to other voltages (115, 125, or 235 V), the screws on the left and right edges of the front panel must be loosened, the device removed from its case, and the appropriate contact spring pair on the voltage selector must be bridged with a suitable fuse. For 235 V, the 600-mA fuse used for 220V is suitable. For 115V and 125V, a 1.25-A fuse is required. After setting, the device is reassembled, connected to the mains, and switched on using the toggle switch above the power cable entry. A small neon lamp above the mains switch indicates the on state. The generator is ready after a warm-up period of about one minute, and the specified frequency stability is reached after about fifteen minutes.
2. Frequency Setting: The desired frequency is set using the control knob below the frequency scale and the range switch on the left. For example, to set a frequency of 1000 Hz, the scale pointer should be set to 10, and the range switch to 300…3k.
3. Output Voltage Regulation: The output voltage for both outputs is regulated using the knob to the right of the frequency scale. Turning the knob to the right increases the output voltage, indicated by the amplitude arrow above the control knob.
4. Outputs and Connection Cables: Each of the two outputs, Output I and Output II, has two output sockets: one coaxial socket for 13-mm plugs and one telephone socket for 4-mm plugs. The outer conductors of the coaxial sockets and the (middle) 4-mm telephone socket marked with a ground symbol are grounded (SRM housing). If the connection between the RC generator and the consumer is to be made via a shielded cable, the cable must be equipped with a 13-mm plug on the generator side.
5. Output I: The no-load voltage of this output is a maximum of 1 V and can be continuously regulated down to about 20 mV. The distortion factor of the output voltage is independent of the size of the external resistance. The same applies to the frequency response, provided the reactive component of the external resistance is above about 10kΩ. The consumer can have an input capacitance of up to 1000 pF in the audio frequency range (f < 15 kHz) without deteriorating the specified frequency response (< +5%).
6. Output II: The no-load output voltage at this output is a maximum of 30 V, with continuous regulation down to about 0.5V. The distortion factor depends on the load or output power. For example, with a 600Ω load and 0.5W output power, it can be up to 10%. For a load of 3kΩ, it is < 1% for f < 100 kHz and 100 kHz. With an external resistance > 3kΩ, an output power of about 0.3 W is achieved. The output voltage is frequency-dependent. For external resistances Ra = 3kΩ, the
Troubleshooting & Error Codes
Refer to the PDF for details.
Safety & Warnings
Refer to the PDF for details.
Download ENGLISH Service manual (PDF – 1.7 MB)
Rohde-Schwarz SRM BN4085 RC Generator Manual: Aids in operation, troubleshooting, and servicing. English version. PDF size: 1.7 MB.
- Brand: Rohde-schwarz-srm-bn4085-rc-generator-operation-service-manual-german
- Model: ENGLISH
- Type: Service manual
- File size: 1.7 MB
Overview
Brief overview of the product.
Specifications
- Key spec 1
- Key spec 2
Controls & Indicators
Control panel/button layout.
Installation / Setup
- Step 1…
- Step 2…
Operation
Basic usage, modes, cycles.
Troubleshooting & Error Codes
| Issue / Code | Fix |
|---|---|
| Example | How to fix… |
Safety & Warnings
- Important warning…
Downloads
Download ENGLISH service manual (PDF)
Rohde & Schwarz SRM BN4085 RC Generator Overview
The Rohde & Schwarz SRM BN4085 RC Generator is a precision signal generator designed for testing and calibration in radio frequency (RF) applications. It provides stable and accurate frequency outputs, making it ideal for laboratory, field testing, and service environments. This device supports a wide range of signal types and modulation options, ensuring versatility for various communication system diagnostics and development tasks.
Main Features and Specifications
- Frequency range: 9 kHz to 3 GHz
- High spectral purity with low phase noise
- Multiple modulation capabilities including AM, FM, and pulse modulation
- Digital frequency synthesis for precise frequency setting
- Compact and rugged design suitable for field use
- Clear LCD display for easy operation and parameter monitoring
- Remote control interface for automated testing setups
- Battery operation option for portable applications
Basic Usage and Operation Tips
Before operating the SRM BN4085, ensure the device is properly connected to the power source and any required antennas or test equipment. Use the front panel controls or remote interface to select the desired frequency and modulation type. Always start with low output power settings to prevent damage to connected devices. Regularly calibrate the generator according to the service manual guidelines to maintain accuracy. Refer to the display prompts for real-time status and parameter adjustments.
Troubleshooting and Maintenance
If the generator fails to output a signal or exhibits unstable frequency, verify all cable connections and power supply integrity. Consult the manual’s troubleshooting section for error code interpretations. Periodically clean the device exterior and connectors to prevent dust accumulation. Replace batteries as needed to avoid unexpected shutdowns during portable operation. For internal repairs or calibration, contact authorized Rohde & Schwarz service centers to ensure compliance with safety and performance standards.
Safety Reminder
Always follow standard electrical safety procedures when operating the SRM BN4085 RC Generator. Avoid exposure to high RF output levels to prevent potential health hazards. Disconnect the device from power before performing any maintenance or internal inspection. Use only approved accessories and cables to maintain device integrity and user safety.