16 Jan
2013
16 Jan
'13
9:16 a.m.
Hi Chuck,
I just reviewed the datasheets. The pinout appears *mostly* compatible -
appart from the fact that the 4116 pin 8 wants +12V, and the 4517 only
+5V. The other power supply pins have changed to N.C., so it could be
done with a small board change or a small wire by each IC.
I was just considering that because I have a machine with 64 x 4116 (and
maybe some more in two or three other boards, don't want to look
now...), and I would be interested in reducing power dissipation.
It may go to 170 mW per chip, ... but while MOSTEK say their 4116 needs
up to 1 W max, I just see the TMS4116-20 more probably has 462 mW. So it
would save me... 19 W at best. Or less, because the unused power rails
cannot simple be turned off - or more, because the PSU is a rather
large, old, linear type.
Now well - I don't have time; the originals are soldered in, so don't
want to ruin the boards anyway. Nor change their original state more
than needed for actual repairs. I've already replaced one defective IC
of these, so I could at least test compatibility...
Has anybody ever replaced memory ICs to save power?
Btw., I *might* have to stick with 1 bit RAM in this machine because it
might mask individual bits in hardware, IIRC.
Kind regards, Joerg
On 16.01.2013 06:07, cctalk-request at classiccmp.org wrote:
Message: 5
Date: Tue, 15 Jan 2013 14:43:39 -0800
From: Chuck Guzis <cclist at sydex.com>
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Subject: Forgot to post here...16Kx1 DRAM NOS at Goldmine
Message-ID: <50F5DB9B.9050107 at sydex.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I posted this on Erik Klein's forum awhile back, but also meant to post
this here.
Electronics Goldmine has new 2-per-package MCM4517P12 16Kx1 DRAMs for $1
for two ICs. These are the single-supply version of the 4116 3-rail
devices and I believe, entirely pin-compatible.
Might be a good deal for someone looking for replacement DRAM.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G19239
Cheers,
Chuck
--
-------------------------------------------------------------------
Dr. med. J?rg M. Sigle +41-76-276-8694
http://www.ql-recorder.com +41-32-51-22-944
http://www.jsigle.com Have a lovely day... +49-176-964-35413
16 Jan
16 Jan
2:19 p.m.
Now well - I don't have time; the originals are
soldered in, so don't
want to ruin the boards anyway. Nor change their original state more
than needed for actual repairs. I've already replaced one defective IC
of these, so I could at least test compatibility...
For me it is STUPIDITY to solder memories on board. They fail, and when
they fail, they FAIL.
I'd take all of them out with a professional desolder station, replace
it with sockets and using whatever memory you feel like. This is something
I'm quite used to do.
I'm on a slow network to find direct links, but look at
http://tabajara-labs.blogspot.com for the ZX-80 and Gradiente Expert (MSX)
computers
all-chips-removed-board-restored-and-turned-pin-socketted-treatment
2:59 p.m.
On Jan 16, 2013, at 4:16 AM, "Joerg M. Sigle" <joerg.sigle at jsigle.com>
wrote:
Hi Chuck,
I just reviewed the datasheets. The pinout appears *mostly* compatible -
appart from the fact that the 4116 pin 8 wants +12V, and the 4517 only
+5V. The other power supply pins have changed to N.C., so it could be
done with a small board change or a small wire by each IC.
I was just considering that because I have a machine with 64 x 4116 (and
maybe some more in two or three other boards, don't want to look
now...), and I would be interested in reducing power dissipation.
And reliability (which is probably directly correlated with power
dissipation).
Has anybody ever replaced memory ICs to save power?
Btw., I *might* have to stick with 1 bit RAM in this machine because it
might mask individual bits in hardware, IIRC.
For reliability, sure. Lots of people with 4116 boards make the
appropriate mods (or build up dozens of adaptor PCBs) to install
4164s in their place. You're only using 1/4 of the memory, but
the massively increased reliability is worth it for a lot of
people (I got two Defender board sets, and the ONLY bad ICs on
them were one burned out 74LS138 and about eight dead 4116s.
You do save a lot of power, too, but aside from heat issues
(which can, of course, be important), the power draw isn't always
as consequential for people running vintage hardware. It is a
lot nicer to old power supplies, though, and it can get rid of
a pesky -5v rail on the board that's often not used for anything
else.
- Dave
5:53 p.m.
In article <B9BE82A3-3557-4B11-89C9-5202D8ADE2E9 at gmail.com>,
David Riley <fraveydank at gmail.com> writes:
For reliability, sure. Lots of people with 4116
boards make the
appropriate mods (or build up dozens of adaptor PCBs) to install
4164s in their place. [...]
It seems that these little adapter circuit boards would be useful to
have from a standard source. At the very least, it would be nice to
have open source hardware designs for them. Is anyone doing that?
--
"The Direct3D Graphics Pipeline" free book
<http://tinyurl.com/d3d-pipeline>
The Computer Graphics Museum <http://computergraphicsmuseum.org>
The Terminals Wiki <http://terminals.classiccmp.org>
Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>
7:36 p.m.
On Jan 16, 2013, at 12:53 PM, Richard <legalize at xmission.com> wrote:
In article <B9BE82A3-3557-4B11-89C9-5202D8ADE2E9 at gmail.com>,
David Riley <fraveydank at gmail.com> writes:
I swear I saw the PCBs somewhere, but perhaps I dreamed them up;
this little hack is easy enough to do straight on the chip, but
it would be a pain to do the NCs with through-hole parts unless
you offset the board by 100 mil (which would cause spacing
problems in a lot of closely-spaced RAM arrays):
http://www.robotron-2084.co.uk/gifs/4164hack.gif
The other thing that is often done is to convert the board en
masse to 4164s by rewiring the power supplies, but that relies
on the +12v and -5v supplies being unused by the rest of the
system (as is the case with Defender, but quite probably not
with other boards):
http://www.robotron-2084.co.uk/techwilliams4164.html
You could make an adaptor board by stacking two boards with a
header running up through the center (I've seen similar things
with EEPROM burner adaptors), but it's a bit clunky and it can
be difficult to keep the two layers' back-side pins from
touching. Still doable, though, which is better than not.
The other thing to do is alter an IC socket as a "pass-through
adaptor" to do what the above animated GIF specifies. That's
easy enough to do and doesn't run the risk of forcing the holes
of your target socket too wide (as with .025" square-post pins).
Can be quite a bit of work to make sure the NC socket pins
don't contact the target socket pins, but it's doable.
- Dave
For reliability, sure. Lots of people with 4116
boards make the
appropriate mods (or build up dozens of adaptor PCBs) to install
4164s in their place. [...]
It seems that these little adapter circuit boards would be useful to
have from a standard source. At the very least, it would be nice to
have open source hardware designs for them. Is anyone doing that? 
8:31 p.m.
On Wed, Jan 16, 2013 at 2:36 PM, David Riley <fraveydank at gmail.com> wrote:
I swear I saw the PCBs somewhere, but perhaps I
dreamed them up;
this little hack is easy enough to do straight on the chip...
http://www.robotron-2084.co.uk/gifs/4164hack.gif
You can cut the pin off at the shoulder and leave just enough
stub left to tack the jumper wire and run it over the top, even
in a dense RAM array. Just don't try to solder past the bend
and it should fit. The solder and wire bump will be up, not
sticking out the side.
The other thing that is often done is to convert the
board en
masse to 4164s by rewiring the power supplies, but that relies
on the +12v and -5v supplies being unused by the rest of the
system (as is the case with Defender, but quite probably not
with other boards):
I've seen some that could be hacked that way, but yes, not all.
Dynamic PETs, for one, only use -5V for the RAM array. Remove
the 7905 and it should be safe. I'd have to check the schematics
for +12V but IIRC, it's not used anywhere else. IIRC, the tape drive
motor is powered from another part of the PSU.
The other thing to do is alter an IC socket as a
"pass-through
adaptor" to do what the above animated GIF specifies. That's
easy enough to do and doesn't run the risk of forcing the holes
of your target socket too wide (as with .025" square-post pins).
Can be quite a bit of work to make sure the NC socket pins
don't contact the target socket pins, but it's doable.
If you poke the two pins out of a machined-pin socket with a hot
soldering iron, you only have to ensure the 4164 pin doesn't extend
below the plastic socket shell and you won't get -5V or +12V
where you don't want it. You'd still want to carefully solder the
jumper wire to the DRAM to avoid lateral shorts, but you could
try soldering _under_ the chip into the 90-degree bend of the
legs and the wire would be protected from the board by the
adapter socket.
Given how easy 4164s are to get compared to 4116s, I don't mind
clipping pins or soldering wires to them. I do have a small pad
of spare 4116s, but if I really had to replace a bunch, I'd probably
sacrifice a necessary number of 4164s for the older hardware.
It's not like I'm melting them down by the pound.
-ethan
8:55 p.m.
My thought was that if you couldn't simply connect the +12 supply line
to +5 for the entire board, you could at least locate the supply trace
for the DRAM array, cut it, and wire it to +5. It's unlikely to be
hooked to a buried PCB plane.
FWIW, I thought the price wasn't bad for NOS low-power devices.
--Chuck
9 p.m.
On Jan 16, 2013, at 3:55 PM, Chuck Guzis <cclist at sydex.com> wrote:
My thought was that if you couldn't simply connect
the +12 supply line to +5 for the entire board, you could at least locate the supply trace
for the DRAM array, cut it, and wire it to +5. It's unlikely to be hooked to a buried
PCB plane.
FWIW, I thought the price wasn't bad for NOS low-power devices.
No, that price is excellent. It's about half what Jameco charges
for 4116s in single quantity, and they're the most reasonable I
commonly see (but maybe I look in the wrong places).
- Dave
5:43 p.m.
New subject: Retrofitting for power savings (was: Forgot to post here...16Kx1 DRAM NOS at Goldmine)
In article <50F66FD8.3040203 at jsigle.com>,
"Joerg M. Sigle" <joerg.sigle at jsigle.com> writes:
It may go to 170 mW per chip, ... but while MOSTEK say
their 4116 needs
up to 1 W max, I just see the TMS4116-20 more probably has 462 mW. So it
would save me... 19 W at best. Or less, because the unused power rails
cannot simple be turned off - or more, because the PSU is a rather
large, old, linear type.
Won't you get more savings by replacing the linear PSU with a switching PSU?
--
"The Direct3D Graphics Pipeline" free book
<http://tinyurl.com/d3d-pipeline>
The Computer Graphics Museum <http://computergraphicsmuseum.org>
The Terminals Wiki <http://terminals.classiccmp.org>
Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>
7:13 p.m.
New subject: Retrofitting for power savings (was: Forgot to post here...16Kx1 DRAM NOS at Goldmine)
On Jan 16, 2013, at 12:43 PM, Richard <legalize at xmission.com> wrote:
"Joerg M. Sigle" <joerg.sigle at
jsigle.com> writes:
Depends on the relative efficiency of the linear vs. the switcher
at the given output voltage, and how much power is being run
through the power supply. Usually the answer is yes, but it can
also be the case that you're primarily concerned about the power
dissipated by the board itself because it can cause more heat
(and thus reliability) issues; obviously, whichever saves the
most power will also produce the least overall heat, but the
heat generated by the PSU is often vented out of the box a lot
more efficiently (not always).
- Dave
It may go to 170 mW per chip, ... but while
MOSTEK say their 4116 needs
up to 1 W max, I just see the TMS4116-20 more probably has 462 mW. So it
would save me... 19 W at best. Or less, because the unused power rails
cannot simple be turned off - or more, because the PSU is a rather
large, old, linear type.
Won't you get more savings by replacing the linear PSU with a switching PSU? 
5:49 p.m.
Joerg M. Sigle wrote:
Hi Chuck,
I just reviewed the datasheets. The pinout appears *mostly* compatible -
appart from the fact that the 4116 pin 8 wants +12V, and the 4517 only
+5V. The other power supply pins have changed to N.C., so it could be
done with a small board change or a small wire by each IC.
I was just considering that because I have a machine with 64 x 4116 (and
maybe some more in two or three other boards, don't want to look
now...), and I would be interested in reducing power dissipation.
It may go to 170 mW per chip, ... but while MOSTEK say their 4116 needs
up to 1 W max, I just see the TMS4116-20 more probably has 462 mW. So it
would save me... 19 W at best. Or less, because the unused power rails
cannot simple be turned off - or more, because the PSU is a rather
large, old, linear type.
Now well - I don't have time; the originals are soldered in, so don't
want to ruin the boards anyway. Nor change their original state more
than needed for actual repairs. I've already replaced one defective IC
of these, so I could at least test compatibility...
Has anybody ever replaced memory ICs to save power?
Btw., I *might* have to stick with 1 bit RAM in this machine because it
might mask individual bits in hardware, IIRC.
Kind regards, Joerg
People have replaced 4116s with 4164s after cutting the -5 and +12
supply lines to the RAM banks to improve reliability:
http://www.robotron-2084.co.uk/techwilliams4164.html
The above link is for converting a video game motherboard power
connector to eliminate the -5/+12 lines without cutting lines on the
motherboard.
There is also a link there for simply replacing single 4116s with 4164s:
http://www.robotron-2084.co.uk/gifs/4164hack.gif
Note that the 4164 is not using the entire device's memory - only 16k is
actually used. Enabling the other 48k would require more wiring and
these RAM chips are extremely inexpensive so using three banks of them
is much cheaper than rewiring one bank to 48k (time, eh?).
John :-#)#
On 16.01.2013 06:07, cctalk-request at classiccmp.org
wrote:
Message: 5
Date: Tue, 15 Jan 2013 14:43:39 -0800
From: Chuck Guzis <cclist at sydex.com>
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Subject: Forgot to post here...16Kx1 DRAM NOS at Goldmine
Message-ID: <50F5DB9B.9050107 at sydex.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I posted this on Erik Klein's forum awhile back, but also meant to post
this here.
Electronics Goldmine has new 2-per-package MCM4517P12 16Kx1 DRAMs for $1
for two ICs. These are the single-supply version of the 4116 3-rail
devices and I believe, entirely pin-compatible.
Might be a good deal for someone looking for replacement DRAM.
http://www.goldmine-elec-products.com/prodinfo.asp?number=G19239
Cheers,
Chuck
8:10 p.m.
On Jan 16, 2013, at 12:49 PM, John Robertson <pinball at telus.net> wrote:
People have replaced 4116s with 4164s after cutting
the -5 and +12 supply lines to the RAM banks to improve reliability:
http://www.robotron-2084.co.uk/techwilliams4164.html
The above link is for converting a video game motherboard power connector to eliminate
the -5/+12 lines without cutting lines on the motherboard.
As I mentioned in my other email (which might not have made it through
yet), that method works as long as the -5 and +12 aren't used elsewhere
in the system, and as long as the +5 can be safely rerouted to the +12
rail. That is true of Defender (because the regulated +12v and the -5v
are only used on the RAM; the audio board makes use of the unregulated
+12v as do some others), but is less of a safe bet on more complex
systems. Really handy on most early Williams boards, though. :-)
- Dave
4368
days inactive
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days old
12 comments
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