HP9830 memory / was Re: Still looking for Infotek MX-30 RAM
hp-fix at xs4all.nl
Fri Dec 5 14:12:10 CST 2014
> -----Oorspronkelijk bericht-----
> Van: cctalk [mailto:cctalk-bounces at classiccmp.org] Namens tony duell
> Verzonden: vrijdag 5 december 2014 19:26
> Aan: General Discussion: On-Topic and Off-Topic Posts
> Onderwerp: RE: HP9830 memory / was Re: Still looking for Infotek MX-30 RAM
> > > I assume you're jsut going to be plugging into the HP9830 I/O slot
> > Yes. I'm considering putting the mass storage ROM on the I/O slot card
> > also (similarly to how the sector buffer works), but since that ROM is
> > hard-addressed, that won't actually free up the ROM slot it would
> > normally occupy.
> I don't really see the point. It's fairly easy to make a ROM cartridge
> EPROMS (IIRC 2 EPROMs, a 74x00 and a couple of transistors (to convert the
> 12V selects back to 5V). Such a board (hand wired) was shown at HPCC a
> of years ago.
> If you do make your own Mass Memory ROM module, figure out a way to have
> a switch to disable it. The Mass Memory ROM intercepts all sorts of BASIC
> commands, to the extent that DISP and PRINT (at least) fail unless there
> working disk drive connected too. Continually plugging and unplugging the
> is hard on the connectors (yes, you can still get them, but desoldering
> one is a pain).
> Incidentally, the ROM module connector on the 9830 (but not on the smaller
> machines) is 0.125" pitch, double sides, 18 pins on each side. Now where
> you seen that before :-). It made finding an extender board very easy when
> fiddling in that area.
For who is interested, I'm busy designing a replacement rom board so failing
boards can be replaced ( I know at least 3 9830 with failing rom's)
I'm ready with the artwork of the connector fingers 2x10 and 2x25
(Ultiboard), if any one wants a copy of those drop me a line offlist.
The board will support 27C64 to 27C256 eproms, at first when the board is
ready I'll order a prototype serie.
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