[time-nuts] 10811 Repair (was warmup / bad batch)

Dr Bruce Griffiths bruce.griffiths at xtra.co.nz
Mon Jan 22 21:53:59 EST 2007


Jack Hudler wrote:
> A Crystal is not a apply DC power get oscillations out.
> I think of it like a crystal glass that get thumped with your finger and the LC
> resonator(s) keep it going and keep it pure.
>
> Start reading 8-88 and pay attention to 8-95 if you don't have any output.
>
> Jack
>
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf
> Of Jason Rabel
> Sent: Monday, January 22, 2007 7:50 PM
> To: richard at karlquist.com; 'Discussion of precise time and frequency
> measurement'
> Subject: Re: [time-nuts] 10811 Repair (was warmup / bad batch)
>
> What voltage goes to the crystal? I may have had my scope scale too high and
> just didn't notice, but at first glance I don't think it was getting power.
>
> Jason
>  
>
> -----Original Message-----
>
> Yes, the black wires are the thermistor.
>
> The crystal has three wires.  Two are actually connected
> to the crystal electrodes.  The third is the case.  The
> case is fastened to the casting with a screw.  The only
> way the casting gets an electrical ground is by way of the
> crystal ground screw and ground wire to the board.
> The wires are welded to the crystal, so if you want to
> disconnect one of them, you have to unsolder it from the
> PC board.
>
> Rick Karlquist N6RK
>
>
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>   
Jack
Paragraph 8-96 states:
OUTPUT AMPLITUDE HIGH OR LOW. Many times this can be cured by the 
adjustment of R6 as
described in paragraph 5-14. If the correct amplitude cannot be obtained 
with this adjustment,
monitor the signal at Q6(C) with an oscilloscope and set R6 to obtain an 
amplitude of 2.8V p-p.
Then check Q5 and Q9 stages. If the R6 adjustment isn't effective, you 
should suspect the AGC
circuitry (Q3, CR4, CR5, C5, C6, R5, R6, R7, or Q1).

The only problem is that according to the schematic Q6 is part of the 
oven controller circuit.
Surely they mean Q2(C)??

Bruce



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