NA7RH
-
Seneca Notes
Back to NA7RH AM Page
|
|
|
|
 This
PDF file contains some Heathkit VHF-1 (Seneca) problem solutions and
modifications encountered in getting my Heathkit VHF-1 Seneca on the
air. (click here)I had the good fortune to acquire a Seneca that was originally well built and remained relatively unmolested. The arrangement of items below is in their approximate order of encounter in proceeding through the Testing, Adjustment and Calibration Instructions section of the Heathkit Assembly Manual. With these changes, I have added no new holes, nor done anything else that is irreversible. Bob, NA7RH 3-18-2009 VFO Hum, Frequency Shift and Drift when Driver is Keyed Tube Substitutions and Tube Condition 6AQ5 Clamp Tube Oscillation 2-meter Neutralization and Screen Lead Inductance Noise and Hum modulation due to Mike input susceptibility to RF Power Supply 120 Hz Hum in Speech Amplifier Electric Field Induced 120 Hz Hum in Speech Amp Input Arcing Relay Contacts at HV Transformer Center Tap Band Switch Mechanism Loose Dial Glass Link Coupling Assembly Error Unresolved Issues with the Seneca |
||
|
|
|
|
|
|
Schematic
diagram of the VHF-1 Seneca for reference in support of the above modification notes (in GIF format). |
|
|
|
|
|
 |
Front view of the Heathkit VHF-1 Seneca transmitter. |
|
|
|
||
