[time-nuts] Cheap 5370A on eBay

Orin Eman orin.eman at gmail.com
Sat Dec 20 12:47:50 EST 2014

On Sat, Dec 20, 2014 at 12:12 AM, Poul-Henning Kamp <phk at phk.freebsd.dk>

> --------
> In message <BLU170-W651E405EA49CC0FE9E42D0CE680 at phx.gbl>, Mark Sims
> writes:
> >I believe there are 5370 ROM dumps on KO4BB.COM
> They're also in the BBB-5370 repos.
> >I few years back i posted on this forum how  I restored a 5370A
> >that had a missing ROM board by installing an EEPROM into the empty
> >socket on the CPU board.  I did have to jumper a couple  of address
> >lines to the EEPROM and perhaps tweak the data buffer enable signal...
> >it's been a while.  The 5370A normally uses a separate ROM  board
> >containing the firmware in several ROM chips.  I read out those
> >chips from a good machine and merged the data into a single EPROM.
> One detail to be aware of if you do this, is that the HP5370 uses
> inverters as address line buffers.

I suppose that would affect the order in which you merge the ROMS into a
single (E)EPROM, but that's hardly necessary any more.  The images in the
BBB repos are in the reversed order necessary for programming a new ROM.  I
had to reverse the order to disassemble the code...

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