Diggy,
I have wondered about just this question. After all, there are several types of “alcohol”, like methanol, ethanol, rubbing alcohol, mineral spirits, de-natured alcohol, etc. I hope that someone on the list will PLEASE tell me which (specifically) kind of “alcohol” to use to wash off the remaining rosin flux from my hand soldered circuit boards. Thank you! Bob Pigford From: M100 [mailto:[email protected]] On Behalf Of Diggy Dude Sent: Monday, May 07, 2018 12:00 PM To: [email protected] Subject: Re: [M100] 8K RAM module Brian, Gotcha. What would you clean it off with? Acetone? Ethanol? De-Oxit? On Mon, May 7, 2018 at 10:35 AM, Brian White <[email protected]> wrote: He meant that after building, the flux must be washed off. You can't leave the dried flux in there, even if it is "no-clean" flux, because the flux will leak enough current to matter. On Mon, May 7, 2018, 10:42 AM Diggy Dude <[email protected]> wrote: 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. > >
