petel@tekig.UUCP (Pete Lancashire) (04/20/84)
Many people have asked me for information on the different Diablo
printers so here is a history of the Diablo letter quality printers.
It was written by, and is reproduced with the permission of,
Steve Roberts, president of "The Printer Works".
[a little editing has been done ..pl]
[a plug for The Printer Works is the end]
DIABLO PRINTERS
Diablo printers fall into six basic categories: the chronological order of
their development was HyType I, Hytype II, Model 630, Model 620.
Each of these categories has many variations.
HYTYPE I PRINTER
The HyType I is the "Grand-Daddy" of the daisy wheel printer.
According to industry folklore, the HyType I was not the first daisy wheel
printer. Apparently, the first one was created in the design labs of the
Singer-Friden company. An early Diablo employee recalls that 13 of the
first 15 Diablo employees hat worked at Singer on a hard disk drive
project. The Singer management was considering cancelling the project when
they learned that the design team had a working prototype a month ahead of
schedule. Management then considered selling the the project, but the
interest from other companies was so great management decided to pursue the
project, but not in time to prevent the many-talented design team from
leaving to found Diablo Systems Incorporated in 1969. The first
"Hyper-Typer", as it was almost named, was kept in a vault. XEROX liked
the machine and bought the company in 1972. About 100,000 Hytype I's were
built between 1972 and 1978. Today, OEM's (Original Equipment Manufactures)
scrap them for the gold content or sell them for as little as $4000.00 per
hundred! Enough Trivia.
The HyType I is still considered a reliable work-horse by many
users. The print speed is fairly fast, about 35 characters per second
(cps), but there are several features of the HyType I that detract from its
popularity. The electronics are on three large printed circuit boards, two
of which are mounted underneath the printer mechanism. This makes them
difficult to trouble-shoot. The interface is a custom parallel which is not
compatible with the Centronics type of IEEE-488 parallel interfaces
available on many microcomputers [and bigger to ..pete]. The interface
problem can be solved for $200 to $500 by purchasing a specialized interface
board that converts the Diablo parallel to RS-232 or Centronics parallel. A
potential HyType I buyer should know that an external power supply is
required, the shortest horizontal motion increment is 1/60th on an inch,
which means that good "Boldface" printing is not possible and every
character is struck with the same hammer energy. This last trait tends to
wear out small characters, such as periods, while leaving large characters,
such as "M", not quite as dark as they ought to be. With the exceptions of
the print-wheels enclosures, and paper-feed motors, every part of a HyType
I is different from the corresponding part on the HyType II. There is also
a XEROX version of the HyType I which has a different set of circuit
boards. A HyType II platen can be installed on a HyType I but not visa
versa. Power supplies are compatible between HyType I's and HyType II's,
but an internal supply for a HyType II will not fit inside the HyType I.
HYTYPE II PRINTERS
The HyType II first appeared in 1976. The five to eight circuit
boards are small and mounted in a motherboard for easy removal and
troubleshooting. The entire mechanism was made faster, more durable, and
more accurate than the HyType I. The HyType II can move its carriage
horizontally to an accuracy of 1/120th of an inch, at an effective slew
rate of 500 characters per second! The hammer energy is varied depending on
character size for better print quality and print wheel life. The frame is
a rigid aluminum casting with larger diameter carriage rails. The paper
carrier assembly allows complete adjustment of platen position. An internal
switching power supply can be mounted in a space underneath the platen
between the print carriage and circuit cards.
There are four main modules in the 1300 series. The 1345A is the
most common. It prints with a plastic printwheel only, at about 45 cps. It
was sold with or without a case and power supply. Most OEM's bought it with
the Diablo case, and many bought the internal power supply. OEM's added
their own control panels, and keyboards. The cover sets came in receive
only (RO) and keyboard send receive (KSR) styles. Some of the RO covers had
short slots in the front for small limited control panels. The KSR cover
used by OEM's had a keyboard hole that was cut smaller than those used on
the HyTerms, this is not very convenient for those of us who like to
reconfigure these units into 1640's. Other options available included
ribbon-out sensors, and paper-out switches, split platen, bottom-feed
chute. Two of the eight circuit board slots were left open for customer
use. Many microcomputer owners who bought these parallel interface printers
as used OEM equipment and are using one of the spare printer slots for a
serial to parallel converter card.
The 1355WP is similar to the 1345A but it uses a metal print wheel
for better print quality, hence the initials WP, for word processing. The
carriage uses a printwheel motor with a longer motor block which supplies
the extra torque required to spin the heaver metal wheel. The longer motor
block required more drive current. The printwheel amplifier or "PAM" had to
be altered. The hammer drive circuit, which is on the same board, also puts
out a little more juice. Diablo did not want people putting plastic
printwheels in machines designed for metal ones so they put the characters
in different positions. The character positions are determined form the
ROM's located on the logic II board. All other circuits and motors are
usually the same.
Brief Note: Metal versus Plastic printwheels
In out opinion, the print quality from a new plastic
printwheel and a fresh carbon ribbon is just as good as that from a
metal printwheel. The advantages of using metal printwheels are
bolder type, longer printwheel life and the availability of
proportional type styles. Diablo has unfortunately chosen to make
true proportional wheels in metal only [just came out with them ..pl].
Qume and other companies make true proportional wheels in plastic,
but when they are installed on Diablo printers the platen height
needs to be raised to compensate for the sightly longer petals. For
improved print quality on the meal wheel machines the print speed
is slowed about 5 cps and they are set-up to advance more ribbon.
Metal printwheels cost much more than plastic printwheels. A
typical price for a metal printwheel is 45 to 65 dollars where as a
plastic printwheel is usually only 5 to 9 dollars.
The 1355HS is the hot rod of the Diablo line; the letters HS stand
for high speed. It uses plastic printwheels only, and prints at 55 cps. It
uses a long block printwheel motor for faster positioning. All of the circuit
boards are modified versions of the standard 1345A cards with the exception
of the Logic I and the transducer boards. The carriage amplifier (CAM)
drives a motor fitted with heat sinking fins. The carriage features a
black-anodized, light-weight cast alum frame.
The 1380WB was a limited production, wide-bed printer. Nicknamed
the "Broadway", it features a double-wide print line of 264 10-pitch
characters and 316 12-pitch characters. The 1380WB is based on the 1355WP
metal wheel word processing printer mechanism. A two carriage version was
developed, but never went into production.
HyTerms using the HyType II Mechanisms
Also called the 1600 series, HyType II HyTerms use standard RS-232C
serial interfaces for direct connection to modems, terminals, and
computers. HyTerms come in RO versions to run directly from computers or
from extension ports in CRT terminals. The KSR version is intended for use
as a printing terminal, or, in local mode, as a typewriter. Feedback from
uses indicated that they do not make good typewriters as the ribbon and
printwheel block the user's view of the characters being typed. Scroll and
autoveiw features have been added to roll the paper up when the typeist
pauses, but most people find this feature very distracting.
The first HyTerms were the 1610 and the 1620. The 1610 is an RO
printer and the 1620 is a KSR terminal. All of the circuitry is the same,
the only difference being the addition of a keyboard on the 1620. The
mechanism in both the 1610 and the 1620 is essentially a 1345A; in fact,
many are found with both a 1345A serial number tag and a 1610 or a 1620
serial number tag. Like the 1345A, the print speed is 45 cps and only
plastic wheels can be used. A Xerox version of the 1620 exists under the
name XEROX 1700. The incoming RS-232C data is processed by an 8080
microprocessor on either a HPR01 of HPR02 board. The HPR02 is functionally
the same as the HPR01 but uses a slightly different set of IC's. The Logic
1 of the 1345A is replaced by an expensive multilayer version that runs the
command signals from the HPROx board to the 8080 interface card. The
control paned on the 1610 and 1620 is adequate but was improved for the
later HyTerms.
The next HyTerm designed was the 1641. It is basically a XEROX 1720
terminal with the ability to communicate using IBM 2741 protocol. The
control panel and the keyboard on the 1641 had more features including
individual lights for ribbon-out, paper-out, parity error, and overflow
error instead of just one non-descriptive error light that left the
operator confused as to what was wrong. The 1641 uses the same boards as
the 1610 and the 1620, except that the HPROx board is a HPRO3. Extra
program memory and input buffer memory was added with a XMEM1 board which
filled the last remaining slot in the HyTerm II printer mechanism.
The last HyTerms are the 1640 and 1650, both available in RO and
KSR configurations. The 1640 uses plastic printwheels, and is basically a
1345A mechanism. The 1650 uses metal printwheels and is similar to the
1355WP mechanism. The interface and control electronics are extremely
advanced and are located on a single board called the HPRO4. The HPRO4 uses
three separate microcomputers; two 8041A's, and one 8085 to do the jobs of
the HPRO3, the XMEM1, the 8080 interface, and the Logic 2. The control
panel has more features than the 1641, and there are 3 extra slots to add
XMEM2 boards which can hold many optional PROM programs. THE 1640s AND THE
1650s ARE LIKELY TO BE CONSIDERED THE BEST DAISYWHEEL PRINTERS EVER BUILT.
[I agree, non come even close ..pl]
DIABLO MODEL 630
The 630 comes in five different configurations: an OEM printer, a
basic RO terminal, an expanded RO terminal, a basic KSR terminal and an
expanded KSR terminal. A nice feature of all 630 printers is that they can
use both metal and plastic printwheels. The print speed is a little slower
than HyType IIs, typically 33 to 40 cps.
Model 630 PPI/HPRO6 (Diablo Parallel printer)
---------------------------------------------
This unit is equipped with a parallel interface that is compatible with the
Diablo parallel interface for the Hytype II or Qume Sprint Micro 3 printer.
The model 630 PPI is a low-cost alterative to those who need a parallel
interface and can provide enhancements such as graphics with the host
system software.
Model 630 SPI (Simplified Serial Terminal)
------------------------------------------
This is a low-cost RS-232C serial RO terminal. This unit lacks some of the
enhancements found on the standard 630, but does have proportional spacing
as a standard feature.
Model 630 HPRO5 BASIC (Serial Terminal - Basic)
----------------------------------------------
This unit is equipped with all of the functions of a basic communications
terminal. In addition, it contains extensive internal self-diagnostics
capability. Is is available in either RO or KSR configuration.
Model 630 HPRO5 EXPANDED (Serial Terminal - Expanded)
-----------------------------------------------------
This unit contains all of the features of the 630 HPRO5 - Basic plus word
processing enhancements, vector plotting, expanded print buffer , "here
is...", answer back, nonvolatile parameter memory, and remote diagnostics.
These upgrades are accomplished by adding additional firmware, additional
RAM and EAROM, and a small battery to the HPRO5 circuit board.
Model 630 API (All Purpose Interface)
-------------------------------------
The model 630 API uses special cable assemblies for direct connection to
RS-232C, Centronics parallel, and IEEE-488 type interfaces. It can do true
proportional spacing, and other enhancements found in the HPRO5 - Expanded.
Model 630 ECS (Extended Character Set)
--------------------------------------
The 630 ECS features a special carriage to print characters that are formed
on the middle as well as the outer end of the printwheel spokes. These
special print wheels contain up to 192 characters. [also very expensive
..pl]
DIABLO MODEL 620
The Diablo 620 is a new low-cost machine designed for light duty
applications. [i.e. personal computer etc. don't recommend ..pl] The
mechanism is based on a XEROX typewriter design, and non of its parts are
interchangable with the other Diablo printers. INCLUDING the PRINTWHEELS,
25 cps......., [I would consider a TEC/C.ITOH, uses standard Diablo wheels
and ribbons ..pl]......
PLUG from a very satisfied customer, me:
I'll skip the plug (my net-conscience you know). If you want to know more
about the The Printer Works, I will individually mail to you.
Pete Lancashire
uucp: ...tektronix!tekig!petel
ARPAnet: tekig!petel.tektronix@Rand-relay (I think)
Ussnail: Pete Lancashire, Tektronix Inc., MS 19-680, POB 500
Beaverton, OR 97077
ddd: (503) 627-2566