[time-nuts] Opening an Isotemp OCXO

[paul swed]

Man O man I am loosing track here.
The s30 makes it a ttl part. So 12 V would have smoked it.
Seems like an easy fix for that piece at least.
Regards
Paul
WB8TSL

On Fri, Oct 28, 2016 at 3:28 PM, Peter Reilley <preilley_454 at comcast.net>
wrote:

> That seems the most reasonable thing to do.
>
> Pete
>
>
> On 10/28/2016 3:20 PM, Tom Miller wrote:
>
>> It looks like that is the only device that could be damaged by 12 volts.
>> Can you find a replacement and try running at 5 volts?
>>
>>
>> ----- Original Message ----- From: "Peter Reilley" <
>> preilley_454 at comcast.net>
>> To: "Discussion of precise time and frequency measurement" <
>> time-nuts at febo.com>
>> Sent: Friday, October 28, 2016 3:10 PM
>> Subject: Re: [time-nuts] Opening an Isotemp OCXO
>>
>>
>> The reason that there was 12 volts on the unit was because I put it
>>> there. I should
>>> have tried 5 volts first but the only datasheet that I could find said
>>> 12 volts.
>>> All the eBay units that look the same say 12 volts.
>>>
>>> Pete.
>>>
>>> On 10/28/2016 12:53 PM, paul swed wrote:
>>>
>>>> I confirmed the pin out matches a 74s30 also. An S30 is TTL. Great pix
>>>> to
>>>> look at.
>>>> So 12 V on a 5 V chip is indeed a smoker. Find out why there was 12 V.
>>>> OK crazy talk I see a 1K resistor next to the VCC chip. Would anyone be
>>>> crazy enough to use a dropping resistor from 12 V to get 5?? Really bad
>>>> engineering and I don't actually believe they would. But if true a open
>>>> 74s30 would indeed show 12 V on pin 14.
>>>> Good luck.
>>>> Paul
>>>> WB8TSL
>>>>
>>>> On Fri, Oct 28, 2016 at 12:48 PM, jimlux <jimlux at earthlink.net> wrote:
>>>>
>>>> On 10/28/16 9:13 AM, Scott Stobbe wrote:
>>>>>
>>>>> The OCXO82-59 datasheet lists 12V supply, 5V clock out, could also be a
>>>>>> blown regulator in your ocxo, if it is indeed a 12v model.
>>>>>>
>>>>>> There you go..the design could use a 74S30 as a driver - it's fast,
>>>>>>
>>>>> fairly good drive, but runs off 5V.  If the regulator is shorted, and
>>>>> you
>>>>> put 12V on it, it will cook.
>>>>>
>>>>>
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