[time-nuts] pm - re: Dallas NV-SRAM replacement? (in 3458A)

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Jun 8 14:58:11 EDT 2010


In message <FBCMCL01B01FRaqbC8w0009c8bf at FBCMCL01B01.fbc.local>, Marco IK1ODO wr
ites:

>>I replaced all the NVRAM's in mine last month, no issues.
>>
>>There are plenty of NVRAMs to be had as new.
>
>that's good news. What have you used?

TI's BQ4011YMA-70N and STM's M48Z12-70PC1 

I soldered low profile sockets in to make it easier in 2020 or
whenever... :-)

>>You can read out the memory with the undocumented "MREAD" command,
>>but the CALRAM is protected by various tricks, so you cannot just
>>use the MWRITE command to restore it.
>
>So, have you read the RAM with an eprom-programmer, and then rewrote 
>them, or simply replaced?

I read and wrote them with a eprom-programmer, that was the easiest...

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.




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