18 May
2005
18 May
'05
1:46 p.m.
Does anyone have any information about this IC? I have two of them. I
found them in the memory section of an Intel 8008 based computer. The other
RAMs are Intel 1101s so I'm guessing that these are equivelent parts but I
want to be sure. The date code on these is 7114 and they're white ceramic
with gold lids and faint grey traces to each leg. Here
<http://www.classiccmp.org/hp/i8008-1/close-up.jpg> is a picture of the
board with the two ICs installed. The ICs in the top row are 1702 EPROMs.
The 1101 RAMs are in the second row. These two parts are the 2nd and 3rd
parts from the RH end. FWIW I have a 1970 and a 1973 Fairchild catalogs but
neigher one lists any uA36xx parts.
Joe
18 May
18 May
5:10 p.m.
I (too) can not find a reference for the uA3656 in the Fairchild Full Line Condensed
Catalog (1975).
However, I believe Fairchild's naming convention is that "uA..." would
indicate analog or interface functionality.
Speculation #1:
If there are some connections from the uA3656 to the 1101s (or 1702s) (but not
pin-for-pin parallelling) it may be a TTL<->MOS
sense-amplifier/driver/level-converter. Early MOS memory chips used external drivers/sense
amplifiers, and specialised ICs were produced for those functions.
For example, I found Motorola refs for DS3645/75 (hex 3S latch driver for MOS mem),
DS3647/77 (quad 3S MOS mem IO reg), MC3461 (dual NMOS Memory Sense Amp) (from Motorola
Linear 1976).
Perhaps it is from the Motorola DS36.. line, but second-sourced from Fairchild.
Speculation #2:
An A/D or D/A converter (perhaps connected to the nearby D connector?).
BTW & FWIW:
On your web page about the AMI S6800 (http://www.classiccmp.org/hp/ami/ami.htm), you
wonder what the FCM7002 IC is.
It is a clock/calendar chip, like those used in the 1970s for constructing digital clocks:
the FCM7001 (aka CT7001) was a clock/calendar chip with multiplexed 6-digit 7-segment
display outputs. If I have it correctly, on the FCM7002 the 7-segment outputs are replaced
with BCD outputs. (... built a clock using the 7001, and saw the 7002 on a real-time-clock
I/O board for the TI-990 in the late 1970s, must have been rather awkward for the board
designers to interface.)
"Joe R." wrote:
Does anyone have any information about this IC? I have two of them. I
found them in the memory section of an Intel 8008 based computer. The other
RAMs are Intel 1101s so I'm guessing that these are equivelent parts but I
want to be sure. The date code on these is 7114 and they're white ceramic
with gold lids and faint grey traces to each leg. Here
<http://www.classiccmp.org/hp/i8008-1/close-up.jpg> is a picture of the
board with the two ICs installed. The ICs in the top row are 1702 EPROMs.
The 1101 RAMs are in the second row. These two parts are the 2nd and 3rd
parts from the RH end. FWIW I have a 1970 and a 1973 Fairchild catalogs but
neigher one lists any uA36xx parts.
Joe
6:39 p.m.
At 05:10 PM 5/18/05 -0700, you wrote:
I (too) can not find a reference for the uA3656 in the
Fairchild Full Line
Condensed Catalog (1975).
However, I believe Fairchild's naming convention is that "uA..." would
indicate analog or interface functionality.
Looking at the catalog that does seem to be the case. However I have no
idea why someone whould put TWO analog ICs in RAM sockets. Also all of the
analog parts in the catalog have three digit part numbers and nothing close
to 3656 so I'm still wondering what I have here. However the date code
makes me think that these aren't 1101s. I don't think they were available
that early and I'd be surprised if any of the second source companies
released their part before Intel did. I need to check on the release date
for the 1101.
Today I got a line on the guy that had these and dumped them. I'm going
to try and locate him and see what he can tell me.
Speculation #1:
If there are some connections from the uA3656 to the 1101s (or 1702s)
(but not
pin-for-pin parallelling) it may be a TTL<->MOS
sense-amplifier/driver/level-converter. Early MOS memory chips used
external drivers/sense amplifiers, and specialised ICs were produced for
those functions.
That's possible however they are definitely in sockets that are supposed
to have 1101s. BELIEVE IT! I have four complete baords and I pulled parts
from about 12 more so I'm CERTAIN that these
sockets are supposed to
contain RAM. I'm not saying that these parts are RAM but
I'd be rather
surprised if someone put an analog part in a RAM socket and I'd be doubely
surprised if they put two of the same parts in adjacent RAM sockets.
For example, I found Motorola refs for DS3645/75 (hex 3S latch driver
for MOS
mem), DS3647/77 (quad 3S MOS mem IO reg), MC3461 (dual NMOS Memory
Sense Amp) (from Motorola Linear 1976).
Perhaps it is from the Motorola DS36.. line, but second-sourced from
Fairchild.
Interesting idea. I'll take a look at the Motorola catalog and see if
they have something with a similar number. If so I'll compare the packages.
Speculation #2:
An A/D or D/A converter (perhaps connected to the nearby D connector?).
You know, I don't know what those two D connectors are for. They're
inside the case when it's assembled and covered up and aren't connected to
anything. I expect that they're some kind of test connector. But I should
trace them out and see where they go.
BTW & FWIW:
On your web page about the AMI S6800
(http://www.classiccmp.org/hp/ami/ami.htm),
you wonder what the FCM7002 IC is.
It is a clock/calendar chip, like those used in the
1970s for constructing
digital clocks: the FCM7001 (aka CT7001) was a clock/calendar
chip with
multiplexed 6-digit 7-segment display outputs. If I have it correctly, on
the FCM7002 the 7-segment outputs are replaced with BCD outputs. (... built
a clock using the 7001, and saw the 7002 on a real-time-clock I/O board for
the TI-990 in the late 1970s, must have been rather awkward for the board
designers to interface.)
Thanks for that information. I'm still trying to find docs for the
S6800. A couple of people said that they had them but no one's turned them
up yet.
Joe
"Joe R." wrote:
Does anyone have any information about this IC? I have two of them. I
found them in the memory section of an Intel 8008 based computer. The other
RAMs are Intel 1101s so I'm guessing that these are equivelent parts but I
want to be sure. The date code on these is 7114 and they're white ceramic
with gold lids and faint grey traces to each leg. Here
<http://www.classiccmp.org/hp/i8008-1/close-up.jpg> is a picture of the
board with the two ICs installed. The ICs in the top row are 1702 EPROMs.
The 1101 RAMs are in the second row. These two parts are the 2nd and 3rd
parts from the RH end. FWIW I have a 1970 and a 1973 Fairchild catalogs but
neigher one lists any uA36xx parts.
Joe
19 May
19 May
1:27 a.m.
That's possible however they are definitely in
sockets that are supposed
to have 1101s. BELIEVE IT! I have four complete baords and I pulled parts
from about 12 more so I'm CERTAIN that these sockets are supposed to
contain RAM. I'm not saying that these parts are RAM but I'd be rather
OK, forget my speculating, I didn't realise you knew that 1101/RAM was supposed to be
in those sockets. As weird as it might be, it sure looks to me like somebody stuck the
wrong ICs in there.
FWIW, there is an article about state-of-the-art memories, and in which the Intel 1101 is
described, in "Electronics World" magazine from October 1970 (by Robert Noyce,
of Fairchild/Intel/planar IC fame).
4:02 a.m.
At 01:27 AM 5/19/05 -0700, Brent wrote:
supposed
to be in those sockets. As weird as it might be, it sure looks to
me like somebody stuck the wrong ICs in there.
I think you're right. But I'd still like to know what these are. I'm
beginning to wonder if they might be "house marked" Fairchild parts given
the odd numbering. If so I'll probably never figure out what they are.
That's
possible however they are definitely in sockets that are supposed
to have 1101s. BELIEVE IT! I have four complete baords and I pulled parts
from about 12 more so I'm CERTAIN that these sockets are supposed to
contain RAM. I'm not saying that these parts are RAM but I'd be rather
OK, forget my speculating, I didn't realise you knew that 1101/RAM was
FWIW, there is an article about state-of-the-art memories, and in which
the Intel
1101 is described, in "Electronics World" magazine from October
1970 (by Robert Noyce, of Fairchild/Intel/planar IC fame).
Interesting. I wonder if my local libraries microfiche goes back that far.
Joe
7158
days inactive
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