Chuck,
No it is nothing that sophisticated. It is just a standard RAM board with
circuitry and BIOS to emulate a HDD. Here is the only blurb I could find on
it online:
"Solid-state disk emulator
The Blue Flame III solid-state, nonvolatile disk emulator boosts access
speed by up to 20 times. The DOS compatible card is an I/O mapped device
built from 14 SIMMs. It features a
16bit data path and transfers data up to 4 Mbytes/s. Capacities range from 2
to 56 Mbytes. Each card fits in a full length, I6-bit ISA bus slot.
Semi Disk Systems; from $595."
Based on this info it seems to max out at 4MB 30 pin SIMMs. I am guessing
this was initially because of a lack or expense of 16MB SIMMs. I wonder if
the BIOS would support a board full of 16MB SIMMs?
In any case it is a pretty neat card although simple. I think the NiCd
batteries, which are soldered on BTW, are for when you need to move the card
from one system to another as there is facilities built
on the card to
attach an external battery (included) with a charger. I am sure that
battery
is dead as well but that is another story.
The Supercapacitor is an interesting idea. I wonder if cost is what is
keeping people from using it on mother boards to replace coin batteries.
Worse comes to worst I will use the generic Chinese battery. I just worry
about no name batteries in a device where I don't have direct visualization.
-----Original Message-----
From: cctalk-bounces at
classiccmp.org [mailto:cctalk-bounces at
classiccmp.org]
On Behalf Of Chuck Guzis
Sent: Tuesday, September 09, 2014 11:00 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Replacement NiCd Rechargeable Batteries for SemiDisk Card
On 09/09/2014 09:28 AM, Ali wrote:
I have a battery backed ISA RAM card by SemiDisk. It
currently has a
number of Panasonic P-25AA 1.2V 250MAh rechargeable Nickel Cadmium
batteries. Given the card date backs from 1990 I am guessing the
batteries are a bit dead and I'd like to replace them. However, my
Googlefu did
not turn up anything.
Does anyone know if Panasonic still makes these
batteries and if so
where I can purchase some in the USA? I did find some Chinese generic
batteries:
http://www.amazon.com/Size-Rechargeable-Battery-250mAh-NiCd/dp/B005NRS
QS8# but I am not sure as to the quality of said battery. Any help is
appreciated in sourcing some batteries. Thank you.
If it's SRAM and a rechargeable battery, I might be tempted to substitute a
"keeper" supercap. Here's a paper from Cooper-Bussman:
http://www.digikey.com/Web%20Export/Supplier%20Content/CooperBussmann_283/PD
F/CooperBussmann_PowerStor_KSeries.pdf?redirected=1
Some of the pinball folks are using Panasonic supercaps for SRAM backup
supplies and report retention times on the order of 45 days between power
cycles.
If that's enough for you, then you may want to consider using a component
that doesn't have the liability of leaking.
Another alternative is to simply use a primary battery, such as a couple of
AA alkaline cells and a Shottky diode or MOSFET to block the reverse
(charge) current. An AA in this application should last its shelf life.
I've got a couple of old systems set up with AAs that are still going
strong after 10 years. The added advantage is that you can separate the
battery from the device to avoid damage should the battery leak.
I've wondered about the use of a solar cell operating off of normal room
lighting and a supercap for memory/RTC retention. If you stash your
equipment in a dark closet, that's maybe not a good idea, however.
--Chuck