[time-nuts] Broken Ovenaire OSC 85-50
WarrenS
warrensjmail-one at yahoo.com
Sat Jul 4 05:05:57 UTC 2009
> Thus one cannot arbitrarily increase Vcc without considering the consequences ...
True, but with the AC voltages as low as they are, I do think it is safe to think that the crystal current should be higher.
I was not suggesting to arbitrarily rise the Vcc, I was asking any chance it is at the wrong voltage???
Even though 2.49 volts is plenty of Vcc to design an osc circuit to run on, It seems like a low, funny voltage to design for, on what I assume is an old product.
ws
*******************
----- Original Message -----
From: "Bruce Griffiths" <bruce.griffiths at xtra.co.nz>
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Sent: Friday, July 03, 2009 8:36 PM
Subject: Re: [time-nuts] Broken Ovenaire OSC 85-50
> WB6BNQ wrote:
>> I agree with Warren. The VCC seems way too low. Interestingly, noone else seems to think so,
>> or did not notice it.
>>
>> Bill....WB6BNQ
>>
>>
>>
> It was noticed, but it is consistent with the resistor values used in
> the circuit.
> The crystal current is determined by the dc emitter current of the
> oscillator transistor.
> Thus one cannot arbitrarily increase Vcc without considering the
> consequences for the crystal current etc.
>
> Bruce
>> WarrenS wrote:
>>
>>
>>> Here is my two cents worth
>>> 20 mv output, sure sounds like something is broken.
>>> It should be fixed before it is modified.
>>> The 2.49 volts on the Red input voltage seem LOW, More Vcc maybe.
>>> The "Grn" labeled wire, FreqCtrl input should be about 1/2 VCC for testing.
>>> If you do 'need' to modify the gain,
>>> It would seem better to bypass the 470 ohm resistor with a cap in series with the 47 ohms.
>>>
>>> ws
>>>
>>
>>
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