[time-nuts] 5065 photo/lamp problem

[Magnus Danielson]

Hi,

Yes, I've already figured that part out. They are far from unobtainable.
It then comes down to figuring out a quick enough way to get them, but
I've not had time to sit down and ponder the options. If I order from a
something like Elfa or similar, what else should I get... and well then
I need to think about things.

Cheers,
Magnus

On 2020-01-15 03:38, paul swed wrote:
> Magnus out of curiosity I checked and those transistors are available on
> ebay and other sites at reasonable prices. At least in the US. So thats
> great news for you.
> Regards
> Paul
> WB8TSL
>
> On Tue, Jan 14, 2020 at 9:22 PM Magnus Danielson <magnus at rubidium.se> wrote:
>
>> Hi Paul,
>>
>> Lacking the specific transistor 2N3553 I can for the moment not progress
>> with the rubidium lamp. It's very obvious that the oscillator is not
>> oscillate and hence the lamp is not giving light.
>>
>> A friend might have those in his way to extensive component storage. It
>> has just not materialized so far. Life may interfere with digging around.
>>
>> So, I moved a board over so I could run another 5065 and that way I can
>> do other experiments, with the aim to measure deeper on the maser, which
>> requires to make the 5065s better if possible. Turns out none of the
>> 5065s is having very satisfactory phase-noise, and quick-and-dirty
>> attempt to fix that has improved the state, so it seems that it was for
>> sure the limiting factor for that 5065.
>>
>> But that rubidium lamp shall be fixed and that 5065 become operational too.
>>
>> Cheers,
>> Magnus
>>
>> On 2020-01-15 00:40, paul swed wrote:
>>> magnus
>>> I was following the thread and it went quiet. Have you been able to make
>>> progress on the 5065? Always eager to learn, because one day my 5065 will
>>> fail.
>>> Regards
>>> Paul
>>>
>>> On Mon, Jan 6, 2020 at 5:04 PM <cdelect at juno.com> wrote:
>>>
>>>> Magnus,
>>>>
>>>> If you apply a +20V supply to the lamp connector you should see
>> 125-150ma
>>>> unlit and it drops  bit when it lights.
>>>>
>>>> Also measure from the lamp connector center pin to the outside conductor
>>>> with an Ohmmeter.
>>>>
>>>> You should have around 3.33K. The 1.33K resistor (in series with a 2.0K)
>>>> is a common problem. it can open up or rise in value.
>>>>
>>>> I usually replace this resistor in units I service even if it measures
>>>> good.
>>>>
>>>> I use a 1.3K 2% MOX resistor.
>>>>
>>>> Also check the approx. 12 Ohm resistor on the standoffs to see if it
>>>> opened up.
>>>>
>>>> If  you pull the lamp assy. you can place a spec-A lead and see the RF.
>>>> Should be approx 88Mhz. (not critical)
>>>>
>>>> Once power is applied the lamp  should start (cold) within a minute or
>>>> so, warm it starts fast.
>>>>
>>>> If you place a scope on A7 TP2 and with the lamp assy removed allow some
>>>> florescent lighting to fall into the interior you should see a large 50
>>>> or 60Hz signal from the light falling on the photocell.
>>>>
>>>> That is a quick check of the A7!
>>>>
>>>> Cheers,
>>>>
>>>> Corby
>>>>
>>>> Cheers,
>>>>
>>>> Corby
>>>>
>>>>
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