[rescue] NVRAM for Blade 100/150

Peter Stokes peter at ashlyn.co.uk
Thu Feb 4 12:33:12 CST 2021

Hi Al

I just placed an order with a UK supplier for 16 of these PCB boards. Not as
cheap as going via China, but they are on hols at present and wanted to get on
with it. If anyone is interested in the bare board or with the
connectors/headers let me know. The bare board is working out at B#6.50 each +
postage, the headers and sockets are easily available via Ebay and are pretty

These will also work in any of the systems which used the old M48T59 NVRAMs as
well as the Blades etc.

All the best


Hi All

I have a solution for the 100/150 (may need these for the V100/120 as well, I
forget what works with them). I tried a few models of NVRAM without success,
but I noticed that Maxim/Dallas produce a larger memory version of the DS1553
called a DS1554. The downside is that it is 32 pins, similar pin out and the
same functionality. I tied the extra address pins high and made up a hack to
prove it works.

I have a few orders for them, so am going to use a prototype through plated
board, 32 pin socket and 28 header pins to satisfy them. I am however
ultimately aiming to have some adapter PCBs made which appear to be pretty
cheap if ordered online, so if anyone is interested in any let me know.


o;?Hi All

Anyone have a suggestion for which NVRAM, that is actually available to buy,
works in the Blade 100?

The original M48T59 has been NLA for a long time now and the DS1553 I have
been using is also now NLA. For the OBP3.X systems you can use an alternative
M48T part, but I have not found one to use in the OBP 4.X systems such as the
Blade 100.

As anyone who has played with these parts, using the wrong NVRAM gives an
error on boot of

"(Can't load tod module) Program terminated"


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