>Rex:
>"Question:
>Has anyone measured or calculated the tuning sensitivity of the pin-5
>EFC voltage? (Hz/V number)."
I'm not sure what HEX number was loaded into my 5680A
but the frequency
was just slightly off from 10Mhz. Pin 5 on my 27M4BI quad opamp 'floats" at
2.599V
I have not but it is sensitive and suspect I actually may have the answer
in my notes.
I was pretty much attempting to range it in to match my operating RB and it
did that quite well. But as I say I suspect I could back out the
sensitivity, maybe.
Regards
Paul
On Sun, Jan 15, 2012 at 8:58 PM, Rex
I have read about the EFC mod for the 5680A by Bill Riches and adapted
for external by Arthur Dent. Nice work.
Maybe I missed a detail in all the recent messages --
Question:
Has anyone measured or calculated the tuning sensitivity of the pin-5
EFC voltage? (Hz/V number)
__
Arthur,
Nice pixs well lit with good detail. If only I had spent some time digging
around that would have been much easier to solder to. May change it the
next time I am in the unit.
I do agree that the reg was running pretty hard but you attached it to at
least a 115 degree heat sink. (At least in
>paul swed:
>"Hardest part is attaching the 100K resistor to the ic. Boy thats small."
I didn't solder the resistor directly to pin 5 of the IC. I found that pin 5
was connected to a nearby SMD capacitor that was a little easier to
solder to. Attached is a photo of the correct location if you want
Just did the pot addition to my FE5086 and it works very well
The systems still warming up and its actually apart with external heat
sinks for cooling so I can get to places.
Hitting 8.6 ^ -12 after first eyeball adjustment on the scope drifting 5 ns
in 9:36 minutes. Time to flip from scope mode to
>Look forward doing other tests like voltage sensitivity and bringing
>out the C field for external adjustment.
>EWKehren at aol.com
++
>But how do you adjust the RgO output frequency? That's why I asked if
>A DDS would be used.
>Nevermind. I just found it. The RgO cell can be fre
>Don't forget the cap on the output.
>Bob
+
You can see the tantalum with short leads soldered directly to
the output lead on the 7805 in the photograph.
http://farm8.staticflickr.com/7013/6668466093_90782cf7e9_b.jpg
-Arthur
___
time-n
s won't give you much margin.
>
> Don't forget the cap on the output.
>
> Bob
>
>
>
> - Original Message - From: "Arthur Dent"
> To:
> Sent: Tuesday, January 10, 2012 10:50 PM
> Subject: [time-nuts] Adding adjustment pot to 5680
>
&g
Subject: [time-nuts] Adding adjustment pot to 5680
You are driving the 7805 near its limit. As a rule of thumb,
a TO-220 case can disipate about 1W of power, if it's
free-standing. You have max 100mA with a voltage difference of
10V, resulting in 1W max. Ie the 7805 will be running at a
cons
>You are driving the 7805 near its limit. As a rule of thumb,
>a TO-220 case can disipate about 1W of power, if it's
>free-standing. You have max 100mA with a voltage difference of
>10V, resulting in 1W max. Ie the 7805 will be running at a
>considerable high temperature. As you have there a good h
On Mon, 9 Jan 2012 13:06:12 -0800 (PST)
Arthur Dent wrote:
> On the inside of the case where the DB-9
> pins go through the circuit board, I mounted a 7805 fixed regulator. I
> cut a piece out of pin 4 and connected the output of the 7805 to the
> board side of the pin with a tantalum cap for
I resisted the suggestion to use Twinkies for insulation (and ate them!),
plus tossed out all the other 'good' suggestion for modifications like
using a robotic arm to move a magnet to trim the frequency, and used
a very simple modification that I just completed a few minutes ago; and
it seems
As has been mentioned by Pete and others the majority of the inexpensive
5680 units can only be adjusted for frequency by inputting rs232 info. I am
experimenting with a simple mod to add a fx adjust pot to my unit. I
removed the unconnected "dummy" pot and glued a miniature 100 k pot upside
down
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