You're not going to find a supercap that'll
a) Keep RAM alive as long as a healthy NiCd will, and
2) Fit inside the case. Or inside your trunk, probably...
But what you can do is
1) Use Eneloop "Low Self-Discharge" AAs, which if your RAM
is healthy (not drawing much stand-by current) will keep memory
alive for many years, fully charged.
b) Use a 3 or 5F supercap, which will keep healthy RAM alive for
weeks; plenty of time to recharge or replace your Eneloops.
Why? Eneloops don't leak. Supercaps don't leak. NiCds do.
On 5/13/18, Jeffrey Birt <bir...@soigeneris.com> wrote:
> Update…
>
>
>
> It was the RAM module. After thinking about it after Fugu’s email the other
> day it occurred to me I had done a capture of the standard RAM bank select
> lines (and I happened to dave it) and after looking at it again it looked
> fine. This evening I pulled the standard RAM module out, split apart a 30
> pin DIP socket to make two 15 pin SIPs and plugged in of the option RAMs.
> AND…nothing. Sigh…
>
>
>
> Then I noticed I had not plugged the ROM back in after cleaning the flux
> from the board. So, the ROM was installed, and STRL-BRK done on power up
> and…It’s ALIVE! Bwa-ha-ha-ha! It’s ALIVE!
>
>
>
> I tried reflowing the original standard RAM module and it still did not
> work. I could ohm out each line to each individual RAM chip and maybe get
> lucky and find one open trace, but I would guess that a bad RAM chip is more
> likely. I’ll look into making some more RAM module or buying a few, for now
> I have 16K.
>
>
>
> As luck would have it the second M100 I bought from across the state arrived
> yesterday, I still have not opened it yet. It is supposed to work, got it
> from the original owner who seemed like a nice guy. A grand total of $61
> including shipping. Now I’ll put together an order for enough caps to finish
> recapping the first M100 and re-cap the 2nd one while I’m at it. I also need
> to try and calculate a super-cap size that will at least match the original
> NiCad battery.
>
>
>
> Thanks again everyone (especially Fugu) for your help.
>
>
>
> Jeff
>
>
>
>
>
> From: M100 <m100-boun...@lists.bitchin100.com> On Behalf Of Fugu ME100
> Sent: Thursday, May 10, 2018 10:06 AM
> To: m...@bitchin100.com
> Subject: Re: [M100] SPAM-LOW: Re: New member - question on 'half' alive
> Model 100
>
>
>
> The address could be stuck internally on the RAM so the address line would
> appear OK externally. The fact the ROM runs correctly with the shared
> Address line would indicate the address lines are generally OK. It could be
> floating on the module as you suggest, look to see if there is any
> corrosion on the module and the pins to the module are in good condition.
> Perhaps try reflowing each of the module pins to make sure there are no dry
> joints?
>
>
>
> I am currently looking into producing some sort of test harness for the
> model T however the lack of socket for the 8085 makes it hard to add in a
> test fixture. Even trying to tri-state the 8085 appears difficult as it
> does not tri-state the ALE, all the other lines are OK. Another option
> would be to try and monitor what it does with something that plugs into the
> RAM socket. That way at least there would be a trace showing the bus
> activity. Being able to single step the 8085 might be another option with
> a known ROM in the socket.
>
>
>
>
