[time-nuts] FRSc RB lamp experiment

[shalimr9 at gmail.com]

The LM 158 and LM358 are the same part, just different screening levels and packaging. 
For commercial applications at normal temperatures, the LM358 is fine.

Didier KO4BB


Sent from my Verizon Wireless BlackBerry

-----Original Message-----
From: paul swed <paulswedb at gmail.com>
Sender: time-nuts-bounces at febo.com
Date: Sun, 13 Feb 2011 17:50:18 
To: Discussion of precise time and frequency measurement<time-nuts at febo.com>
Reply-To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] FRSc RB lamp experiment

Thanks Bruce turned out to be C7 leaky. I actually used a LM358 dip with
wires kind of a ugly bug. Then realzed that really was not the issue. It was
c7.
I do not have any lm158s can or dip. Pretty sure they would be hard to come
by these days also.
Something to look for at hamfests this year.
Regards
Paul.

On Sun, Feb 13, 2011 at 2:01 PM, Bruce Griffiths <bruce.griffiths at xtra.co.nz
> wrote:

> paul swed wrote:
>
>> Startup circuit looks like a bad op amp used as a comparator. U1 section
>> a.
>> This is a LM 158. I have a LM 148 on hand suspect they are different in
>> temperature quality. So will look it up and see. This is a common op amp
>> so
>> if the 148 does not work for some reason any numbers of more modern ones
>> will. Accept one issue its a T08 can. What pin was 8? ;-)
>> Regards
>>
>>
>>
> The LM148 (quad 741) and LM158 (dual opamp) have different input common
> mode ranges, that of the LM158 extends to the negative supply it is also
> rated for a large input differential voltage.
> LM158 pin 8 is the positive supply pin.
>
> Bruce
>
>  On Sun, Feb 13, 2011 at 1:24 PM, Magnus Danielson<
>> magnus at rubidium.dyndns.org>  wrote:
>>
>>
>>
>>> Dear Paul,
>>>
>>>
>>> On 13/02/11 18:50, paul swed wrote:
>>>
>>>
>>>
>>>> Magnus it indeed does look very good.
>>>>
>>>> I have re-assembled the various boards and the system locked up as
>>>> normal
>>>> after the warm up period. I do indeed have a failure in the lamp control
>>>> startup crkt.
>>>>
>>>>
>>>>
>>> My R&S does not have a startup circuit, so I can't help on that
>>> particular
>>> detail. I'm sure you will debug it yourself.
>>>
>>>
>>>  The reference after warm up and adjusting the c field is down in the
>>>
>>>
>>>> 1x10-11
>>>> area. Anyhow I adjusted the c field and the systems not fully assembled
>>>> nor
>>>> has it really been stabilized long enough. Was simply curious so I do
>>>> not
>>>> think this is really a very accurate assessment. Especially since this
>>>> is
>>>> time-nuts territory.
>>>>
>>>>
>>>>
>>> At least it proves that you are up and running at least, modulus quirks.
>>>
>>>
>>>  So next steps is to let the unit cook in or maybe I will further
>>> assemble
>>>
>>>
>>>> it
>>>> and troubleshoot the startup crkt. Add the unlock counter. (A pedometer
>>>> and
>>>> opto coupler) and let the system run for a long while perhaps a week or
>>>> so
>>>> to see what really happens.
>>>>
>>>>
>>>>
>>> Sounds like a plan.
>>>
>>>
>>>  Thanks for your guidance and help Magnus. Who would have thought there
>>> was
>>>
>>>
>>>> a
>>>> recovery technique for FRS-c RB references.
>>>>
>>>>
>>>>
>>> Happy to help. Happy to learn of your progress! Happy to hear I
>>> contribute.
>>>
>>>
>>> Cheers,
>>> Magnus
>>>
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>
>
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