hp 54601a nvram substitute

[nixiefreqq]

just acquired an hp54601a.  it was 100% functional and in great shape. 

BUT the dallas 1220 nvram had a date code of 1992.

wanted to replace the dallas chip with an eeprom but it appears a suitable one is unobtainium.

went ahead and substituted the dallas chip with standard static ram, a battery controller chip, and a coin cell.

also installed a 24 pin socket so that i can test an eeprom if any can be found.

calibration went well and the scope is 100% again (and its an easy fix when the coin cell dies).

vertical cal was easily accomplished with the built in dc calibrator (bnc on the rear panel).

delay cal was also easy but requires the use of a 100khz, pulse generator signal with <5ns rise time.

[coromonadalix]

Someone took a chance with an Cypress FM18W08, made an pcb adapter :  https://imgur.com/a/GmKHW4c

and another one talk about an 28c16 taking the place of the Dallas : http://www.repeater-builder.com/motorola/maxtrac/replacing-dallas-nvram.html

[John.S]

Hi,

A full replacement for the EEprom module is the M48Z02-70PC1 from Micro Electronics.
Mouser has 400+ in stock  ( order nr. 511-M48Z0270PC1).

gr. John