To make sure I understand: Clean all pads and leads with flux.Will a flux pen suffice, or should liquid flux be used?
What specific 74HC and SRAM devices do you use? On Mon, May 7, 2018 at 2:45 AM, Francesco Messineo < [email protected]> wrote: > On Mon, May 7, 2018 at 9:08 AM, Diggy Dude <[email protected]> > wrote: > > Thanks, Fugu! > > > > So the modern solution is a single SRAM and capacitor on a SOIC-to-DIP > > breakout? What's the RAM chip they're using? > > and a logic chip (there're a few different approaches here) to combine > the separate chip selects to a couple of addresses and a single select > signal. My own version of the circuit uses the fewest ports possible > (at least if nobody comes up with a different approach I couldn't > think of). > The RAM chip must be a CMOS static ram, 8kx8 and with low power > standby (not all have this feature). The original 8k modules were > specified for 4 uA max standby current, that allows the standby > battery to keep the RAM content for over a month. Usually the suitable > chips have L or LL in the part number, but you better check the > datasheet for the fine details. Most of the suitable RAM chips have a > measured standby current of 0.1 uA (often less) at 3.3V if the chip > select are driven with the correct voltages. At these current levels, > cleaning the soldering flux is a must. I've measured up to 15 uA of > standby current on badly cleaned modules. YMMV. > Glue logic *must* be 74HC family, it has a suitable current draw at > 3.3V standby and suitable speed. In one case I've used 74AHC and it > worked well too. > > > > > -- Jim > > > > On Sun, May 6, 2018 at 10:29 PM, Fugu ME100 <[email protected]> wrote: > >> > >> You could try > >> https://www.arcadeshopper.com/wp/?page_id=11#!/8k-RAM- > module-for-Model-100/p/104430801/category=28313042 > >> > >> They have the M100 modules if you want to buy. > >> > >> If you want to build your own there are PCBs on OSH Park for surface > mount > >> and DIP versions. > >> > >> No need for any pillaging :) > >> > >> From: M100 <[email protected]> on behalf of Diggy Dude > >> <[email protected]> > >> Reply-To: <[email protected]> > >> Date: Sunday, May 6, 2018 at 8:13 PM > >> To: <[email protected]> > >> Subject: [M100] 8K RAM module > >> > >> Anyone know where I can get an additional 8K for my 24K M100 without > >> pillaging another M100? Let's face it: if I got another M100, I'd be > >> inclined to leave it intact. > > > > >
