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

[Kenny Balys]

It may be wise, if you think the time is near, to pull the device and
read off the calibration data.

This may save you so much pain in the future.

The calibration procedure for my trust old Hameg HM-412's is already
hairy enough for me.

Imagine not having to do that because you can simply blow the
new data in.

Also, in the off chance that it does not need to be read/write you
could burn an EPROM with the calibration data.



On 30.04.21 22:32 , Ben Bradley via Synth-diy wrote:
> The vintage computer folks have solved this problem with some models
> of those battery-backed chips by hacking into the battery connection
> and adding a coin cell, I don't know offhand if this can be done with
> the one you have:
> https://www.vcfed.org/forum/forum/genres/pcs-and-clones/62778-new-way-to-replace-ailing-dallas-rtc-chips
>
> On Fri, Apr 30, 2021 at 4:10 PM Jean-Pierre Desrochers
> <jpdesroc at oricom.ca> wrote:
>>
>> 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 ?
>>