[sdiy] Hardware gurus.. I need your opinion here..

Jay Schwichtenberg jschwich53 at comcast.net
Sat May 1 02:01:52 CEST 2021


I'm not familiar with the TDS product line. I am familiar with the 
DPO/MSO/MDO 2K/3K/4K.

There are 2 levels of calibration, factory cal and user cal. User cal is 
based on the data from the factory cal and should be done regularly to 
keep the scope up to snuff, it only takes about 5 minutes. When you do 
user cal you should let the scope warm up for about 30 minutes so things 
heat up and stabilized.

Factory cal takes about $75K of test equipment and about 20-30 minutes 
of time. It does a lot of low level timing and level tweaking.

On the product lines I mentioned the calibration info is stored in flash 
and doesn't need and battery backup.

I'd contact Tektronix and see what they have to say about the Dallas 
chip and calibration. Don't know if they are still as responsive as 
there were but at one time they were really good at answering questions 
like this.

Jay S.

On 4/30/2021 2:16 PM, Brian Willoughby wrote:
> Go ahead and buy the replacement that you think will work, but I wouldn't install it until the original actually fails. I'm assuming that you can still recalibrate after it fails and you finally install the replacement.
>
> My old Tektronix have no memory!
>
> Brian
>
>
> On Apr 30, 2021, at 13:17, Ullrich Peter wrote:
>> Hi Jean-Pierre!
>>   
>> I would go for option one and use a AA or AAA size lithium cell that will last for the next 25 years for sure…
>>   
>> Why?
>> As the lifetime of lithium cells is given in the datasheet for about 10 years. Even if they are not used – just think of self discharge and electrode passivating effects.
>>   
>> Ciao
>> Peter
>>   
>> Von: Jean-Pierre Desrochers
>> Gesendet: Freitag, 30. April 2021 22:08
>> An: Synth-diy at synth-diy.org
>> Betreff: *EXT* [sdiy] Hardware gurus.. I need your opinion here..
>>   
>> I have a full functional old 90's Tektronix TDS350 that I use a lot.
>> I love this Faithfull scope but its Dallas non-volatile Ram DS1630AB-120 has a datecode 9430 (1994, 30th week !)
>> BUT it still keeps its calibration and data memory settings !!
>> Imagine.. more than 25 years after !
>> Well because I don't want to push my luck too far here
>> I decided to replace this Dallas RAM for something more reliable
>> for the next years to come..
>>   
>> 2 choices:
>>   
>> Replace it with a small 28DIP600 pcb hybrid filled with
>> a non-volatile RAM controller IC + a 32k x 8 SRAM
>> using an external connected 3V lithium battery.
>>   
>> OR
>>   
>> Buy a genuine Tektronix Dalals DS1630AB-120 like these ones for sale at $14.99US each.
>> https://www.qservice.tv/vpasp/shopexd.asp?id=12458&bc=no
>>
>> The seller quotes:
>> ".. the date codes are 9510 or -1995, 10th week"
>> ".. all these are genuine parts bought from the tektronix surplus store in Beaverton,"
>>   
>> Here I was aware of the inner battery life span left from the manufacturer's datecode.
>> But the actual DS1630AB specs page 10  says:
>> 9 - Each DS1630 has a built-in switch that disconnects the lithium source until Vcc is first applied by the user.
>> The expected Tdr is defined as accumulative time in the absence of Vcc starting from the time power
>> is first applied by the user.
>>   
>> Sure these could have been connected at least once then the battery
>> countdown started OR these have never been used..
>>   
>> What do you think ?
>
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