[Boatanchors] Globe (WRL) V-10 VFO - Problem with voltage regulation

[Charles Ring]

My schematic, which I thought was from BAMA, shows R4 as 4.7K though the 
decimal point almost bleeds into the 7 and is easily missed. I see that  
the V-10 manual now on BAMA is from you and indeed its schematic shows 
47K. My  V-10 had 4.7K and showed a drop in 0A2 plate voltage when keyed 
of several volts. I paralleled another resistor to bring the total 
resistance down to 1600 ohms and there is almost no visible voltage drop 
on my analog meter. This might be the answer to my chirp problem.

73 de W3NU




On 11/18/2013 2210, Garey Barrell wrote:
> Charles -
>
> As long as it doesn't completely go out, it's ok.  It's a shunt 
> regulator, which means that when the key is up and the oscillator 
> isn't drawing any current, the 0A2 has to draw enough current through 
> R4 to keep it's plate at 150 VDC.  Then when the key is down and the 
> oscillator draws ~10 mA the 0A2 draws less current, keeping the 
> voltage at 150 VDC.  The 0A2 should regulate anywhere from 5 to 30 
> mA.  The resistor should be such that the 0A2 draws about 20 mA key 
> up, for a total of ~30 mA.
>
> If the filter capacitors are leaky, the B+ becomes low, and when the 
> key is down there isn't enough unregulated voltage to keep the 0A2 
> 'lit'.  Another possibility is that R4 has gone up in value, again 
> limiting the available current flow.
>
> A voltmeter on the Plate of the 0A2 should read close to 150 VDC with 
> very little (volt or so) difference between key up and key down.
>
> By the way, the schematic is wrong, R4 is 4.7k NOT 47k.
>
> 73, Garey - K4OAH
> Glen Allen, VA
>
> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
> and TR-4/C Service Supplement CDs
> <www.k4oah.com>
>
> Charles Ring wrote:
>> My V-10 has a chirp which at 20 meters is really awful. Really fit 
>> only for use during the Classic Exchange.
>>
>> A new question: when the VFO is keyed, should the brightness of the 
>> 0A2 stay the same? Mine almost goes out.
>>
>>
>
>


**