[Boatanchors] OA2 Voltage Regulation Question

[Bill Cotter]

NOTE: C1A is 11PF N1500 and C1B is 4PF N80

The caps are in PF.

73 Bill N4LG

At 10:08 PM 9/8/2023, Walt Cates wrote:
>The max allowable change in voltage for the 0A2, with in the range 
>of 5 to 30ma of anode current is 600 millivolts. 200 to 300 
>millivolts is well within spec. C1A and C1B (on some schematics 
>and parts lists C1 11uf and C32 4uf) are most likely causes of 
>drift. Be sure to note the temperature compensation code of each 
>capacitor. Walt Cates, WD0GOF https://wd0gof.com/Hallicrafters A 
>majority of acceptance is not proof of correctness. 
>https://wd0gof.com/bible-study/commentaries/ 
>________________________________ From: 
>boatanchors-bounces at mailman.qth.net 
><boatanchors-bounces at mailman.qth.net> on behalf of wa9wfa 
><whitebear1122 at comcast.net> Sent: Friday, September 8, 2023 8:16 
>PM To: Boatanchors Mailman. Qth. Net <boatanchors at mailman.qth.net> 
>Subject: [Boatanchors] OA2 Voltage Regulation Question For a 
>properly biased OA2, what would you consider normal for changes in 
>regulated voltage over small changes in load current.  I'm working 
>on a Hallicrafters HA-5 VFO, and when I key the VFO, I'm seeing 
>small changes in the OA2 regulated voltage (148V) on the order of 
>200-300 millivolts, and it's kind of drifting up and down.  Is 
>this normal? Now with that said, I need to yet investigate if the 
>OA2 is supplied with enough current, and what the input voltage 
>looks like while being keyed.  I'm hunting down minor changes in 
>output frequency when it's keyed.  Thanks. 73, Scott WA9WFA 
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