Overview
The Motorola 6-6487 is a fixed carbon composition resistor rated at 39,000 ohms (39K) with a power dissipation rating of 1/2 watt (0.5W). This NOS (new-old-stock) component features a ±10% tolerance, making it suitable for general-purpose electronic applications where moderate tolerance is acceptable. Carbon composition resistors like the 6-6487 are prized by restoration specialists and vintage audio enthusiasts for their characteristic frequency response and natural-sounding performance in tube radio and amplifier circuits.
Key Features
- Resistance Value: 39,000 ohms (39K)
- Power Rating: 0.5 watts (1/2W)
- Tolerance: ±10%
- Construction: Carbon composition film on ceramic base
- New-Old-Stock (NOS): Unopened, factory condition
- Low-inductance design suitable for RF and audio frequencies
Technical Specifications
Carbon composition resistors offer unique electrical and thermal characteristics different from modern thin-film or metal-film resistors. The 6-6487 exhibits typical frequency-dependent behavior and can tolerate brief high-current pulses, making it particularly valuable in audio circuits where these characteristics are desired.
Typical Applications
- Vintage tube radio and amplifier restoration
- Audio frequency (AF) signal coupling and biasing networks
- Power supply filtering circuits
- Guitar amplifier and high-end audio equipment
- Test equipment and measurement instruments from the 1960s–1980s
- Hobby electronics and DIY vintage repairs
Compatibility & Replacements
Compatible With
- Tube-based audio amplifiers and preamplifiers
- Vintage radio receivers and tuners
- 1960s–1980s test equipment and instrumentation
- Any circuit requiring a 39K ohm resistor with moderate tolerance
Replaces / Drop-In Replacement For
The Motorola 6-6487 is a direct replacement for any 39K ohm, 1/2W, ±10% tolerance carbon composition resistor position. Compatible with other manufacturers’ equivalent ratings, such as RCA, Philco, or generic carbon composition 39K 1/2W specifications. Verify compatibility with your specific circuit design before installation.
Works With
- Manual circuit design and prototyping
- Vintage tube equipment schematic standards (EIA, RMA color-code marking)
- Any soldering technique compatible with axial lead components
