[time-nuts] Timebase Replacement - Seiko Epson RTC-72421

[paul swed]

Corey welcome to the group.
As i recall those clocks absolutely drifted like that.
Regards
Paul.

On Thu, Oct 3, 2019 at 1:02 AM Corey Sukalich <zappy at xzapx.com> wrote:

> Hi all,
>
> New to the list, but have known of its existence for a while as I know
> others that have been subscribers.
>
> My question pertains to a timebase used in a Schulmerich carillon bell
> tower system from the 1990’s.
>
> The Seiko Epson RTC-72421 Real Time Clock Module (4-bit) is used, but the
> clock ends up walking to a noticeable degree (minutes) over a period of
> months.  Is this expected for the device in question, or could it possibly
> have a defect?
>
> Datasheet available here:
> https://support.epson.biz/td/api/doc_check.php?dl=brief_RTC-72421&lang=en
> <https://support.epson.biz/td/api/doc_check.php?dl=brief_RTC-72421&lang=en>
>
>
> From what I can tell it uses an internal oscillator, so it sounds like I
> would need to find a drop-in replacement or build a module that will
> replace it with a significantly better time standard.  Any advice is
> appreciated as to whether could be accomplished without too much trouble.
> I’ve repaired a few of these systems over time and there are enough of them
> still in the wild that it might be worth me fabricating a module for them.
>
> Also, on the off chance someone is versed in EPROM data recovery or knows
> of a resource for it, I would appreciate that information as well.
>
> Regards,
> Corey
> N9WIV
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