Viking 500

[K9AAL]

I have a VIking 500 that I need to replace the audio gain pot on, so need to remove the front panel.  I need some advice on getting the power switch off. It is the original keyed switch (yep, I have the key!), but the retaining nut is conical in shape and I don't want to damage the panel getting it off.  Any advice would be appreciated!! 

This transmitter has been out of service for a while--so any other other thoughts on bringing it on line would be helpful!

Thanks, George, K9AAL

[WQ9E]

George,

I have never had to take the front panel off mine but a couple of thoughts:

Is the switch not a D shaped style where it fits through the panel with the nut on the back?  Other switches like this I have installed are like this and the front conical piece is fixed to the switch body and the switch is held by the cutout shape and the nut is on the backside of the panel.  For switches of that style there is no need to turn or even hold the front conical piece.

If the conical piece actually is the nut on this, you need to provide some panel protection.

Since I am the cautious sort, I would first put a little bit of the car wax of your choice around the switch and then put some of the blue type painters tape on the panel around the switch.  The blue stuff usually is generally not as bad about lifting paint as regular tape but the wax will offer additional protection just in case.  The tape will help protect the panel from any slips

Then I would unsolder the leads from the back of the switch and assuming this is a round body switch held by a front nut I would use a bit of rubber in a pair of curved jaw pliers to grab the nut and hold it steady and then turn the switch body instead of the nut.  This would reduce the chance of damaging the panel from slipping pliers.

Another option I have used before; not sure if this applies to the 500 since it has been awhile since I have been inside the RF deck.  I assume the reason for removing the front panel is that there is a nut on the front of the chassis and another on the front panel so you need to remove the front panel to remove the nut on the chassis front.  There may be room to slip a straight blade screwdriver or similar tool to hold the chassis front nut in place while you turn the pot itself to remove it.  Then reverse the process with the new pot.  I have done this on several receivers to avoid having to take everything apart potentially causing other damage.

Final note:  The Viking 500 power supply uses a "mechanical delay" relay for providing proper sequencing when going from transmit to receive.  When this is working properly the plate supply is dropped before the antenna relay is released; when the mechanical delay goes away the two events occur simultaneously causing extremely high voltage transients and when this occurs either one or both spark gaps will fire (if they are properly adjusted) or the voltage will find another place to arc to ground which is going to be at the much maligned connectors between the mod/PS deck and the RF deck.  If your mechanical delay has been lost then you can add a small capacitor across the relay coil (around 10-12uf is about right) with an isolating diode to prevent capacitor discharge through other parts of the circuit.  My 500 has the original connectors with no arcing problems whatsoever.  Those connectors are easily capable of handling the normal voltages and if excess voltages are generated they are going to arc to ground somewhere; with better connectors the arc is likely to be somewhere more expensive.

Good luck with your repair.

Rodger WQ9E

 

[WV Hoopie]

I have a VIking 500 that I need to replace the audio gain pot on, so need to remove the front panel.  I need some advice on getting the power switch off. It is the original keyed switch (yep, I have the key!), but the retaining nut is conical in shape and I don't want to damage the panel getting it off.  Any advice would be appreciated!! 

This transmitter has been out of service for a while--so any other other thoughts on bringing it on line would be helpful!

Thanks, George, K9AAL

George,

If memory isn't failing me, there is a nut on the back side of the panel that can be loosen first. Then the bevel nut on the front of the panel is a piece of cake. I've never had the front panel off of my junkston, but I doubt it is much different than a Ranger or the others that used the same VFO. Replace the Chernobyl resistor inside the VFO!

Since it has ben out of service for a while, check all of the resistor values, replace old caps, standard stuff before plugging the beast into the wall socket.

Mine runs better on 240VAC.

[K9AAL]

Thanks!!  Just got interrupted, so will not get to this for a week or so!!  George

[WV Hoopie]

Another bit if info: Memory tells me I had to go to the tool box and find an "old" wrench to grind thinner & shape a bit to fit the nut inside the panel.

Gud luck and keep us posted.

73's
wd8kdg
Craig