Quick progress update: I was able to read the CALRAM via GPIB using a Prologix adapter and Mark's software (via KE5FX). Success! I did not expect the files to be dropped in C:\Users\<login>\AppData\Local\KE5FX\... but I found them.
I also got a TL866II+ universal programmer in the mail today. Nice piece of kit. I had a Dallas DS1225Y with a date code of 8716 that was on an old board (yes, I tend to be a packrat) and surprisingly, the part still had all its data. 32 years later that's pretty good. A 27C256 EPROM on the same board with a similar date code did not turn out OK, the TL866 could not read it, yet I know that board was working when it was put "in storage". How embarrassing the NVRAM outlived the EPROM! Now the hard part, bite the bullet, open up the 3458 and pull the old parts off the CPU board. Maybe I'll wait for a long week end, I like to take my time but I do not like to start something and not finish and have the equipment in pieces. Somehow these projects rarely turn out good. In a related subject, I have a couple of Tek TDS754D that could use new TIMEKEEPER devices, so if the 3458 goes OK, I may do those next. Didier On Sat, Oct 26, 2019 at 3:38 PM Frank Stellmach <frank.stellm...@freenet.de> wrote: > Didier, > > if you have the old board with DALLAS RAMs: > > - make a dump of the CALRAM into a file, as Poul-Henning explained > - buy the 2kB and 2x 32kB DALLAS RAMs, available from several distributors > - DS1220AD-120+ for about 11$/€ and DS1230Y-150+ for about 22$/€ will > do the job > - unsolder the old RAMs, and solder precision DIL sockets instead > - use a programmer like the TL866 to first make an additional download > from the RAM directly > - program the content of the old CAL RAM to the new 2kB one, and insert > all three new RAMs, maybe add these four 32kB RAMs for additional data > buffer > > Alternatively, you can replace the nvSRAMs by FRAMs, description > somewhere in eevblog, or at TiN > > if you have the new board with the SnapHat batteries, you can't upload > the RAM content again, but: > > - buy 2 SnapHat battery replacements > - switch on the instrument > - remove the old batteries > - insert the new batteries, I would support the PCB with something like > isolated plastics, due to heavy bending forces > > video and description at M. J. Lorton (not competent at all, but > instructive) > > Frank > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- volt-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com and follow the instructions there.
