/me hears mention of dead NVRAMs and materializes

Pulled out my UltraBook IIe today, it's fine with a dead NVRAM, just gives you 
the usual "IDPROM contents are invalid" message you see on Suns.

If I'd have to guess, based on past experience, you likely have a counterfeit 
DS1553W or you ordered the DS1553 without the W suffix. The W means 3.3V part. 
On a 3.3V system, the DS1553 5V part will never release write lock-out; 
furthermore, the DS1553 has a power-on reset comparator and will never 
de-assert reset either! I don't know if the UltraBooks use this reset output, 
but if I were designing a system and using the DS1553/W, I certainly would.

A missing DS1742W in a SGI Tezro stops it dead, as does a DS1742 5V part (W 
suffix is, again, 3.3V). Part of what took so long on my designing a 
replacement for the DS1742W was the sacrificial modules that were sent to me 
were...wait for it...Chinese counterfeits! The part numbers from the dissected 
modules were all 5V parts! 

Now the good news is, I can probably make replacements for the DS1553W. I 
already have a prototype replacement for the DS1643, some customer must've 
needed it for a one-off as I've never run more, but that should already be a 
solved problem. I have one or two GW-1643-1 prototypes on hand for testing.

Thanks,
Jonathan

Reply via email to