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

Ullrich Peter Peter.Ullrich at kapsch.net
Fri Apr 30 22:17:45 CEST 2021

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...

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.


Von: Synth-diy <synth-diy-bounces at synth-diy.org> Im Auftrag 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.


Buy a genuine Tektronix Dalals DS1630AB-120 like these ones for sale at $14.99US each.


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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