2 Jan
2004
2 Jan
'04
6:39 a.m.
3 Jan
3 Jan
3:46 a.m.
THANKS. Several relevant chips are there. 9094, for example, is
DTL. They are intermixed. I don't think I buy the statement made earlier
by one party implying that these are emitter source
At 09:39 AM 1/2/2004 -0800, Al Kossow wrote:
I
don't have a reference for exactly "DT uL909759"
--
I'm in the process of scanning the 1969 f data book and have finished the
logic part. The scan will be up at www.bitsavers.org/pdf/fairchild/_dataBooks
later today.
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
4 Jan
4 Jan
6:01 a.m.
Your in much better shape with a DTL part than if it were CTL!
I'm glad to be wrong on this one. FYI, 2114's use CTL for the vast
majority of their logic, just like the 2116's.
The '759' segment of the P/N sure looked like a common CTL part (common
to old HP's anyway).
Jay Jaeger wrote:
THANKS. Several relevant chips are there. 9094, for
example, is
DTL. They are intermixed. I don't think I buy the statement made
earlier by one party implying that these are emitter source
At 09:39 AM 1/2/2004 -0800, Al Kossow wrote:
I
don't have a reference for exactly "DT uL909759"
--
I'm in the process of scanning the 1969 f data book and have finished
the
logic part. The scan will be up at
www.bitsavers.org/pdf/fairchild/_dataBooks
later today.
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
4:42 p.m.
Actually, this stuff I am working on (controller and interface) wasn't
actually made by HP, it was made by IOMEC (except for the two interface
cards in the CPU box itself).
Also, hate to contradict folks, but the HP 2114B itself is pretty much all
TTL. A quick look thru the card drawings of the CPU / memory etc.
revealed only 3 CTL chips and 1 DTL chip -- the rest is either 7400 series
TTL or discrete transistors. I may have missed a couple, but it is almost
all TTL (and I had to make some repairs in memory addressing when I first
got it).
Perhaps the HP2114A was different?
The DTL already tripped me up once. I had a J/K flip flop with both Q and
-Q low. Turns out -Q was wired with the output of another gate as an
apparent ECO (wasn't on the schematic). Sigh. At least with TTL you have
the clue of the part being open-collector to help you realize someone did
that. 8^)
Jay
At 12:01 PM 1/4/2004 -0500, Bob Shannon wrote:
Your in much better shape with a DTL part than if it
were CTL!
I'm glad to be wrong on this one. FYI, 2114's use CTL for the vast
majority of their logic, just like the 2116's.
The '759' segment of the P/N sure looked like a common CTL part (common to
old HP's anyway).
Jay Jaeger wrote:
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
THANKS. Several relevant chips are there. 9094,
for example, is
DTL. They are intermixed. I don't think I buy the statement made
earlier by one party implying that these are emitter source
At 09:39 AM 1/2/2004 -0800, Al Kossow wrote:
I
don't have a reference for exactly "DT uL909759"
--
I'm in the process of scanning the 1969 f data book and have finished the
logic part. The scan will be up at
www.bitsavers.org/pdf/fairchild/_dataBooks
later today.
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
5:45 p.m.
The DTL already tripped me up once. I had a J/K flip
flop with both Q and
-Q low. Turns out -Q was wired with the output of another gate as an
apparent ECO (wasn't on the schematic). Sigh. At least with TTL you have
the clue of the part being open-collector to help you realize someone did
that. 8^)
Years ago I was working on a thing called a 'Solatron DTU', which was
basically a data logger add-on for a DVM (it had a 20 channel input
multiplexer, a real time clock, and output boards for a Facit 4070 punch
and an ASR33 IIRC). Anyway, it wa all DTL inside.
I found a (genuinely) dead JK flip-flop. Found the pinouts from the
schematics (which fortunately I have), and thought I'd found a
pin-compatible TTL replacement. Popped it in, and the darn thing still
didn't work. No, it wasn't a wire-AND connection... It turns out that the
DTL and TTL chips have the same pinout _except_ that Q and Q/ are swapped
round, and that was easy to miss when looking at the databooks.....
-tony
8:10 p.m.
Tony are you talking about the old schul logic?
ed sharpe
----- Original Message -----
From: "Tony Duell" <ard(a)p850ug1.demon.co.uk>
To: <cctalk(a)classiccmp.org>
Sent: Sunday, January 04, 2004 9:45 PM
Subject: Re: Iomec disc drive?
> The DTL already tripped me up once. I had a J/K
flip flop with both Q
and
> -Q low. Turns out -Q was wired with the output
of another gate as an
> apparent ECO (wasn't on the schematic). Sigh. At least with TTL you
have
> the clue of the part being open-collector to help
you realize someone
did
that. 8^)
Years ago I was working on a thing called a 'Solatron DTU', which was
basically a data logger add-on for a DVM (it had a 20 channel input
multiplexer, a real time clock, and output boards for a Facit 4070 punch
and an ASR33 IIRC). Anyway, it wa all DTL inside.
I found a (genuinely) dead JK flip-flop. Found the pinouts from the
schematics (which fortunately I have), and thought I'd found a
pin-compatible TTL replacement. Popped it in, and the darn thing still
didn't work. No, it wasn't a wire-AND connection... It turns out that the
DTL and TTL chips have the same pinout _except_ that Q and Q/ are swapped
round, and that was easy to miss when looking at the databooks.....
-tony
10 Jan
10 Jan
3:23 a.m.
Jay Jaeger wrote:
Actually, this stuff I am working on (controller and
interface) wasn't
actually made by HP, it was made by IOMEC (except for the two
interface cards in the CPU box itself).
Also, hate to contradict folks, but the HP 2114B itself is pretty much
all TTL. A quick look thru the card drawings of the CPU / memory
etc. revealed only 3 CTL chips and 1 DTL chip -- the rest is either
7400 series TTL or discrete transistors. I may have missed a couple,
but it is almost all TTL (and I had to make some repairs in memory
addressing when I first got it).
Perhaps the HP2114A was different?
Yes, bigtime!
The 2114A is nearly all CTL, very much like the 2116, only a bit slower
and much smaller.
I also have a 2114B, but not the schematics for it. I was not aware it
was mainly TTL based, thats good news to me!
The DTL already tripped me up once. I had a J/K flip flop with both Q
and -Q low. Turns out -Q was wired with the output of another gate as
an apparent ECO (wasn't on the schematic). Sigh. At least with TTL
you have the clue of the part being open-collector to help you realize
someone did that. 8^)
Jay
At 12:01 PM 1/4/2004 -0500, Bob Shannon wrote:
Your in much better shape with a DTL part than if
it were CTL!
I'm glad to be wrong on this one. FYI, 2114's use CTL for the vast
majority of their logic, just like the 2116's.
The '759' segment of the P/N sure looked like a common CTL part
(common to old HP's anyway).
Jay Jaeger wrote:
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
THANKS. Several relevant chips are there. 9094,
for example, is
DTL. They are intermixed. I don't think I buy the statement made
earlier by one party implying that these are emitter source
At 09:39 AM 1/2/2004 -0800, Al Kossow wrote:
>
I don't have a reference for exactly "DT uL909759"
--
I'm in the process of scanning the 1969 f data book and have
finished the
logic part. The scan will be up at
www.bitsavers.org/pdf/fairchild/_dataBooks
later today.
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
17 Jan
17 Jan
2 p.m.
New subject: Iomec disc drive / HP 2871 Controller
In working on my disc drive on my HP 2114B (Its a 2870) I have run into a
little problem -- my drawings for the card are apparently out of date.
The drawings I have are in HP manual 02870-9002. The card in question is a
9048. The drawings I have are dated 3/70, and the ECO level on the drawing
is 1384. The card itself is datestamped Jul 9 70, and is stamped with a
number (which I take to the be ECO) of 1566.
The difference is right in the area (Phase 2) where things don't look right.
The card is in Gate B, Slot B7.
If anyone has newer drawings for the 2781 (aka Iomec 1802) I'd really
appreciate a scan of that module (about 5 pages) and a scan of the pinout
chart for that card location (the pinout chart is about half-way thru my
copy of the manual, and the card drawings are nearer the end).
(Hopefully my backplane and card *do* match..... X).
Jay Jaeger
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
21 Jan
21 Jan
2:33 p.m.
New subject: Iomec disc drive / HP 2871 Controller
For those who might want to follow my adventure with the IOMEC disk drive
and controller (aka HP 2870 drive)
At last report, the controller was hung in a state for which the schematics
didn't match the board.
Part of that issue turned out to be an ECO wire I removed which wire-anded
(I haven't quite figured out why it is called a wired-or sometimes, because
in the cases I have seen, if either input is 0 it drags the result down to
zero -- it is a wired-or only in a negative logic sense) the outputs of two
flip-flops together. Putting that wire back got it to advance one more
phase in the state machine.
The next problem is that one of two error flags (also wire "anded") is
inhibiting a flag which would permit advance into the actual write
operation. Temporarily cutting the trace on the circuit board which
brought that trace into the gates indeed allowed the controller to proceed
and write the first sector on a track of a format operation (at least it
transferred the words necessary via DMA to do so -- I have no idea if it
actually wrote anything at this point).
The good news is that the error flag stuff matches the schematic -- so far,
so I have high hopes of tracking that down....
WooHoo.... (and God bless logic analyzers....)
Jay
---
Jay R. Jaeger The Computer Collection
cube1(a)charter.net
7489
days inactive
7508
days old
8 comments
5 participants
participants (5)
-
aek＠spies.com -
ard＠p850ug1.demon.co.uk -
bshannon＠tiac.net -
cube1＠charter.net -
esharpe＠uswest.net