Re: New Timekeeper/RAM clock stops on power loss?

Hello,

On Sat, 29 Mar 2025 09:25:50 -0500 (CDT)
"John D. Baker" <[email protected]> wrote:

> Tired of re-initializing the timekeeper/RAM in one of my SS5s every time
> the power blinks, I finally unstacked it and replaced the timekeeper/RAM
> with a new one (albeit purchased long, long ago now).
> 
> Rather than the stock MK48T08, I used the MK48T59--the same as used in
> the Ultra-5 and others.  Other than having a couple of extra capabilities,
> they appeared to be otherwise identical.  I have done the same replacement
> in other SS5s without issue.
> 
> On this particular machine (or maybe just this particular part), when the
> power is lost (either by utility failure or normal power-down) the clock
> stops ticking.  When powered up again, the OBP reports "Starting real-time
> clock", as if the timekeeper/RAM had been put to sleep using "power-off"
> from OBP (sets "ST" bit in one of the clock control registers).
> 
> The NVRAM contents are retained so I believe the battery has good life
> yet.
> 
> Has anyone seen anything similar, on any flavor/generation of sparc(64)?
> 
> If possible, I can catch it during boot and boot single-user and set the
> date/time.  If I immediately reboot and stop in OBP, the date shows what
> I set it to.  If I then let it boot, NetBSD thinks the clock has started
> from zero.

Sounds like a near dead battery to me. In my experience it first stops
ticking, then forgets its time, then loses nvram. Usually within a week
or two.
I've had varying success with replacements, I had some that died within
less than a year, my latest batch is a handful M48T08 I bought a few
years ago, supposedly made in '99, yet they're still going with no sign
of trouble, one in a U2, the other in an SS20.

have fun
Michael