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Author Topic: Valiant VFO mod. & Zener?  (Read 4253 times)
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stevef
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« on: October 30, 2005, 10:30:28 AM »
I am doing the VFO modification (K6HLO, WB0TOW, etc.) to my Valiant.  Where in the world can I find a 150v, 5w Zener ?

Tnx, Steve KK7UV
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n2bc
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« Reply #1 on: October 30, 2005, 12:40:57 PM »
Just series a bunch of lower voltage jobs.  I used a string of 1N5357's 20V @ 5W - Seven in series will give you 140V @ 35W, the much higher than needed wattage will keep them stable.

Have fun!  73, Bill  N2BC
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K6JEK
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RF in the shack
« Reply #2 on: October 30, 2005, 01:36:45 PM »
NTE part NTE5161A

Mouser part 526-NTE5161A

NTE parts are common as dirt so I imagine Newark and Allied have them too.  I've also purchased high voltage Zeners from Surplus Sales of Nebraska.

Jon
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Steve W8TOW
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« Reply #3 on: November 01, 2005, 09:19:17 AM »
I typically use NTE subs....
gl...remember, if you use the Hammond P-T 124E as a dirver trany,
and either PP or Parallel 12AU7, you must "back" connect it...
vri 73 steve
8tow
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Always buiilding & fixing stuff. Current station is a "Old Buzzard" KW, running a pair of Taylor T-200's modulated by Taylor 203Z's; Johnson 500 / SX-101A; Globe King 400B / BC-1004; and Finally, BC-610 with SX28  CU 160m morn & 75m wkends.
73  W8TOW
stevef
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« Reply #4 on: November 06, 2005, 06:27:39 AM »
Thanks all, I found a Zener.

Steve, What is wrong with the stock transformer? - or rather, why the need to use the Hammond?

TNX, Steve KK7UV
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W3NP
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« Reply #5 on: November 06, 2005, 02:10:35 PM »
Quote from: Steve w8tow on November 01, 2005, 09:19:17 AM
I typically use NTE subs....
gl...remember, if you use the Hammond P-T 124E as a dirver trany,
and either PP or Parallel 12AU7, you must "back" connect it...
vri 73 steve
8tow


Steve - what exactly do you mean by "back connect" it?  Reverse the primary and secondary connections? I have seen mention somewhere of this and using a resistive divider on the "New" secondary to apply grid bias.
What is the reason for "back" connecting?
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---Dave  W3NP
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