The manual for the Sencore CR70 Field Test provides detailed instructions on setting up the CR70 with a universal adapter and a digital voltmeter, including specific control positions and connections for various tests such as removing G1 short, rejuvenation, and auto/manual restore. It also covers troubleshooting steps by measuring bias voltages, cutoff, and filament volts to ensure proper operation and voltage readings.

• Brand: Sencore-cr70-field-test
• Model: SCHEET
• Type: manual
• File size: 49.3 KB

Manual Overview

The Sencore CR70 Field Test manual provides detailed instructions for setting up and troubleshooting the CR70 using a universal adapter and a digital voltmeter (DVM). To begin, connect the universal adapter to the CR70 and configure the controls to specific positions. For removing the G1 short, set the function switch to REMOVE G1 SHORT and press the REJUV button, ensuring the external DVM reads over 350 Vdc. In the REJUV mode, the DVM should also read above 350 Vdc. For AUTO RESTORE, the CR70 should cycle three times with the current meter showing 80-120 mA DC. MANUAL RESTORE involves setting the switch to MANUAL 1 and MANUAL 2 RESTORE, with current readings of 80-120 mA DC and above 150 mA DC, respectively. The BIAS VOLTAGES are checked by setting the function switch to CUTOFF and observing the DVM readings as you switch through different voltages. Adjusting the CUTOFF control should result in a voltage swing of 20 to 400 Vdc. Lastly, to measure filament voltage, adjust the DVM leads accordingly, noting that older CR70 models will display AC voltage.

Quick Issues Covered

• Diagnose G1 short with external DVM reading over 350 Vdc.
• Verify auto restore cycles with current meter reading 80-120 mA DC.
• Check bias voltages using DVM for specific voltage levels.

Overview

Refer to the PDF for details.

Specifications

Refer to the PDF for details.

Controls & Indicators

Refer to the PDF for details.

Installation / Setup

To set up the CR70 for the field test, connect the UNIVERSAL ADAPTER to the CR70 and set the controls to specific positions: F1 to 1, F2 to 2, K to 3, G1 to 4, G2 to 5, gun select to R/B&W, and CRT to Video. Connect a DC voltmeter to the UNIVERSAL ADAPTER with the positive lead to the G1 lead and the ground lead to the K lead. For removing the G1 short, set the FUNCTION SWITCH to REMOVE G1 SHORT and press the REJUV button; the external DVM should read greater than 350 Vdc. For the REJUV function, set the FUNCTION SWITCH to REJUV and press the REJUV button; the DVM should again read greater than 350Vdc. In AUTO RESTORE mode, set the FUNCTION SWITCH to AUTO RESTORE and the external DVM to DC CURRENT, then press the REJUV button; the CR70 should cycle on and off three times, with the current meter reading between 80 and 120 mA DC when on. For MANUAL RESTORE, set the FUNCTION SWITCH to MANUAL 1 RESTORE and press the REJUV button; the current meter should read between 80 and 120 mA DC with no cycling. Then, set the FUNCTION SWITCH to MANUAL 2 RESTORE and press the REJUV button; the current meter should read greater than 150 mA DC. For bias voltages, set the FUNCTION SWITCH to CUTOFF and the external DVM to DC VOLTS; as you switch through different bias voltages, they should be read on the DVM (-68, -52, -36, and -20). For the cutoff, move the positive lead of the DVM to the G2 lead and adjust the CUTOFF control, looking for a swing of 20 to 400 Vdc. For filament volts, move the ground lead of the DVM to the F1 lead and the positive lead to the F2 lead to read the filament voltage on the DVM, which depends on the filament volts set on the CR70. If the CR70 is a run 16 or lower, the filament voltage will be AC.

Operation

To set up the CR70 for a field test, connect the UNIVERSAL ADAPTER to the CR70 and set the controls to specific positions: F1 to 1, F2 to 2, K to 3, G1 to 4, G2 to 5, gun select to R/B&W, and CRT to Video. Connect a DC voltmeter to the UNIVERSAL ADAPTER, with the positive lead to the G1 lead and the ground lead to the K lead.

For the “Remove G1 Short” operation, set the FUNCTION SWITCH to REMOVE G1 SHORT and press the REJUV button. The external DVM should read greater than 350 Vdc.

For the “Rejuv” operation, set the FUNCTION SWITCH to REJUV and press the REJUV button. The external DVM should again read greater than 350 Vdc.

For the “Auto Restore” operation, set the FUNCTION SWITCH to AUTO RESTORE and the external DVM to DC CURRENT. Press the REJUV button, and the CR70 should cycle on and off three times. When on, the external current meter should read between 80 and 120 mA DC.

For “Manual Restore,” set the FUNCTION SWITCH to MANUAL 1 RESTORE and press the REJUV button. The external current meter should read between 80 and 120 mAdc with no cycling. Then, set the FUNCTION SWITCH to MANUAL 2 RESTORE and press the REJUV button. The external current meter should read greater than 150 mA DC.

For “Bias Voltages,” set the FUNCTION SWITCH to CUTOFF and the external DVM to DC VOLTS. As you switch through different bias voltages, they should be read on the DVM (-68, -52, -36, and -20).

For “Cutoff,” move the positive lead of the DVM to the G2 lead. When the CUTOFF control is adjusted, look for a voltage swing of 20 to 400 Vdc.

For “Filament Volts,” move the ground lead of the DVM to the F1 lead and the positive lead to the F2 lead. The filament voltage should be readable on the DVM, depending on the filament volts set on the CR70. If the CR70 is a run 16 or lower, the filament voltage will be an AC voltage.

Troubleshooting & Error Codes

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download SCHEET Manual (PDF – 49.3 KB)

Sencore CR70 Field Test SCHEET manual: Guide for technicians to troubleshoot and calibrate the SCHEET model. PDF size: 49.3 KB.

• Brand: Sencore-cr70-field-test
• Model: SCHEET
• Type: Manual
• File size: 49.3 KB

Overview

Brief overview of the product.

Specifications

• Key spec 1
• Key spec 2

Controls & Indicators

Control panel/button layout.

Installation / Setup

1. Step 1…
2. Step 2…

Operation

Basic usage, modes, cycles.

Troubleshooting & Error Codes

Safety & Warnings

• Important warning…

Downloads

Download SCHEET manual (PDF)

The manual for the Drake SCHEET covers the setup and operation of a 10-meter adaptation for the Drake L7, including replacing the low-pass filter with RD-58 coaxial cable and adjusting the input coils as necessary. It also provides troubleshooting steps such as removing the band switch stop and adding capacitors to the input coil assembly.

• Brand: Drake
• Model: SCHEET
• Type: manual
• File size: 55.7 KB

Manual Overview

The Drake SCHEET manual provides detailed instructions for adapting the Drake L7 linear amplifier for 10-meter operation. The process involves replacing the low-pass filter with a short piece of RD-58 coaxial cable. For later models, technicians should switch the input and output coaxial-cable center conductors to the empty terminal lugs on the low-pass filter board, ensuring not to short the input to the output, which would not remove the filter from the circuit. Retuning the 15-meter input coils might be necessary, and technicians should follow the input-coil adjustment procedure in the owner’s manual. There is no tuning required for 10 meters. The manual also details the removal of the band switch stop, which varies between early and later models. Early models have a removable stop on the band switch index, while later models have a bracket mounted on the bottom plate. Additionally, two 68-pF DM19 or DM20 mica capacitors need to be added to the input coil assembly.

Quick Issues Covered

• Diagnose power-up failures with input coil adjustments.
• Resolve error codes by retuning 15-meter input coils.
• Use schematics for circuit tracing during low-pass filter replacement.

Overview

Refer to the PDF for details.

Specifications

Refer to the PDF for details.

Controls & Indicators

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Installation / Setup

Owners of Drake L7 amplifiers can adapt their devices for 10-meter operation by following specific steps. The process involves wiring adjustments, such as connecting one wire to the jumper across the input wafer and the other to the input side of the 15-meter input coil. The amplifier should be placed upside down for clarity, identifying the 15-meter coil as the one farthest back and on the left, with the input side at the bottom end. The low-pass filter should be replaced with a short piece of RD-58 coaxial cable, and on later models, the input and output coaxial-cable center conductors should be switched to empty terminal lugs on the low-pass filter board. Care should be taken not to short the input to the output at the low-pass filter. The band switch’s stop must be removed; on early models, it is a removable stop on the back side of the band switch index, while on later models, it is a bracket behind the input matching filters. Finally, two 68-pF DM19 or DM20 mica capacitors should be added to the input coil assembly. Retuning of the 15-meter input coils may be necessary, following the input-coil adjustment procedure in the manual. There is no tuning required for 10 meters.

Operation

Refer to the PDF for details.

Troubleshooting & Error Codes

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download SCHEET Manual (PDF – 55.7 KB)

Drake-l-7-information SCHEET manual: troubleshoot and calibrate SCHEET systems efficiently. File size: 55.7 KB.

• Brand: Drake-l-7-information
• Model: SCHEET
• Type: Manual
• File size: 55.7 KB

Overview

Brief overview of the product.

Specifications

• Key spec 1
• Key spec 2

Controls & Indicators

Control panel/button layout.

Installation / Setup

1. Step 1…
2. Step 2…

Operation

Basic usage, modes, cycles.

Troubleshooting & Error Codes

Safety & Warnings

• Important warning…

Downloads

Download SCHEET manual (PDF)