w8khk
Member
Online
Posts: 1200
This ham got his ticket the old fashioned way.
|
|
« Reply #1 on: October 11, 2020, 01:39:38 AM » |
|
The Viking II provides an octal (8 pin) accessory receptacle which may be used with the HG-10 Heath VFO, or the Johnson VFO. (I use an HG-10 with my Viking II, configured as described below).
I would suggest that you first perform a couple tests to verify that the 8-pin receptacle on the Viking II is wired according to the manufacturer's schematic diagram.
First, check continuity from chassis ground to pins 1, 2, 4, and 6 on the accessory receptacle. These should measure close to zero ohms (same as when you short your meter leads together to test the ohms function). These pins should all be connected to chassis ground.
Next, test the keying line, which is pin 8 on the receptacle. With the Viking powered down, and the power plug removed from the power receptacle, measure ohms between pin 8 and chassis ground. It should measure open, or a very high resistance. Now turn on the HV switch on the Viking II front panel (with no power applied to the transmitter). You should measure close to zero ohms with the switch on, confirming that the keying circuit is properly connected to the receptacle.
Next, turn off the HV switch, insert the power cord of the Viking II into a receptacle, and turn on the main power switch.
Measure between chassis ground and the following accessory socket pins:
(When looking at the open end of the receptacle, pins are numbered 1 through 8 in a COUNTER-CLOCKWISE direction, starting at the pin after the center indexing indicator).
Pin 3 should measure approximately +300 volts DC, and the value is not critical.
Pin 7 should measure approximately 6.3 volts AC for the filament of the oscillator tube.
If all these tests prove successful, proceed with replacement of the plug on the HG-10B cable. If not, troubleshoot the individual pins to determine what has been modified on the accessory receptacle circuit.
The HG-10B should have a cable with four wires, black, white, red, and green.
Install an octal plug on the end of the cable with the following pin configuration:
(When looking at the PIN end of the male connector, the pins are numbered in a CLOCKWISE DIRECTION, starting with the first pin after the center indexing indicator.).
Black to pin 1 (Ground)
Red to pin 3 (Positive 300 volts)
White to pin 7 (6.3 volts for tube filament)
Green to pin 8 (Keying line to enable VFO when Viking II is in transmit mode.)
If the colors on your cable do not match the above list, you will need to trace the wires within the HG-10B to determine which wire is used for each function.
Hope this helps, and look forward to hearing your Viking II produce some nice AM signals on the HF bands!
73, Rick
PS: If you do not have manuals with schematic diagrams for your Johnson Viking II and Heath HG-10B, you might want to contact ManualMan.com for high quality documentation for vintage equipment. This could lead to more pleasurable and safer operating conditions as you start to use your new acquisitions.
|