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Author Topic: viking ii & hg-10b  (Read 2511 times)
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k5kab
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« on: October 10, 2020, 09:45:39 PM »

Picked up a HG-10bB VFO to mate with my Viking ii it came with a 9pin octal plug the Viking is only a 8 pin. the heathkit only uses 4 wires but im not sure about the Viking octal diagram. (((((((Help))))))))
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w8khk
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« 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.
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Rick / W8KHK  ex WB2HKX, WB4GNR
"Both politicians and diapers need to be changed often and for the same reason.”   Ronald Reagan

My smart?phone voicetext screws up homophones, but they are crystal clear from my 75 meter plate-modulated AM transmitter
WD5JKO
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« Reply #2 on: October 11, 2020, 11:34:56 AM »


I will just add that the HG-10 loses 160m coverage, and the RF output excitation is lower than on the Johnson 122 VFO, or the Heath kit VF-1.

That said, the HG-10 is a nice VFO, and will probably work on the VII when on 75 and 40m. There may not be enough drive to get frequency multiplication to achive proper 6146 grid current on 20-15-10m. One could replace the VII oscillator/VFO buffer tube, a 6AU6 with a 6AH6. That will increase the gain.

Jim
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k5kab
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« Reply #3 on: October 11, 2020, 10:17:19 PM »

Rick I really appreciate your response.  I would assume you are a school teacher because what a great teach you drafted outstanding information and very precise. Thanks a million.
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k5kab
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« Reply #4 on: October 11, 2020, 10:18:57 PM »

Jim thanks a million can I substitute that tube without any modification?
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k5kab
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« Reply #5 on: October 11, 2020, 10:21:28 PM »

Rick do I need a keying connection are should the viking ii do it. Should I perform the mod for chatod keying
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k5kab
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« Reply #6 on: October 11, 2020, 10:28:00 PM »

Would this viking use block keying  or cathode keying?
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k5kab
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« Reply #7 on: October 13, 2020, 06:17:09 AM »

Ok octal plug installed according to instructions. Vfo Rf out is connected to Vii. What other connection is needed ? What are the keying procedures for the Vii?
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