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Author Topic: Viking Valiant - Chernobyl resistor  (Read 5099 times)
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WZ8J
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« on: May 25, 2017, 12:20:20 PM »

I have a Valiant I on the bench. Looks like someone has already replaced the "Chernobyl" resistor in the VFO with a modern 18K metal oxide type - don't know the power rating - guessing it might be a 2 watt??
So, should I leave it alone or will it also not be up to the task? I know the recommendations call for a 10 Watt. I do have a 10 watt 30K ohm but not sure if that's too much resistance. I recall Timtron suggesting 20-30K Ohm.
What say the collective? Undecided
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KB2WIG
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« Reply #1 on: May 25, 2017, 01:08:36 PM »


When in doubt, replace 'it' with something bigger (power wise).


Check this out......    http://www.amwindow.org/tech/htm/valiantbytron.htm

I would follow El Trons advise and put a 10W 30K in the box. Do it for the children.

klc
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What? Me worry?
RolandSWL
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« Reply #2 on: May 25, 2017, 02:23:44 PM »

Does anyone have a picture of this resistor? How tough is it to replace?

THX..........
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W3RSW
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Rick & "Roosevelt"


« Reply #3 on: May 25, 2017, 04:49:28 PM »

Here it is, R3 in the Ranger, very similar VFO.  It feeds the voltage regulator tube.  You may be able to get to it removing right side cover, but not sure of clearances in your rig.
The whole VFO cage may have to be lifted.

From my manual.
R3 in mine has been replaced outside the vfo enclosure, under chassis at point of voltage origin.


* image.jpeg (256.8 KB, 960x720 - viewed 591 times.)
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RICK  *W3RSW*
WZ8J
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« Reply #4 on: May 25, 2017, 05:04:54 PM »


When in doubt, replace 'it' with something bigger (power wise).


Check this out......    http://www.amwindow.org/tech/htm/valiantbytron.htm

I would follow El Trons advise and put a 10W 30K in the box. Do it for the children.

klc
Thanks KB2WIG
I followed your advice and used the 30K 10 watt. Bit of a pain to get the extended leads attached but not too bad.
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WZ8J
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« Reply #5 on: May 25, 2017, 05:06:54 PM »

Does anyone have a picture of this resistor? How tough is it to replace?

THX..........

you might find this useful too:
http://wireless-girl.com/Projects/AMTransmitters/JohnsonVFOresistor.html
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KC3GMQ
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« Reply #6 on: May 25, 2017, 06:14:45 PM »

This pic of the resistor location from Wireless Girl.  Good information there on this issue

73
Dave


* VALIANTvfo1071.jpg (624.33 KB, 1536x2048 - viewed 658 times.)
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RolandSWL
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« Reply #7 on: May 30, 2017, 09:53:46 AM »

Thanks for the info.

RSWL.......
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