5140 PCC Starter Disk w/APP Selector
30 pin socket
KB, Audio, system clock, I/O controller
Printer, system timer
LCD Controller RAM
DOS 3.2 or higher is required. (to support the
It's a 3.5" 720K Toshiba 4452A0P11 with
a 34 pin edgecard connector. Both floppy drives are jumpered DS1
From Don Hills
There were 2 models of floppy drive: Toshiba and Alps.
The Toshiba used a metal band to drive the heads up and down, the Alps
used a leadscrew. The leadscrew model could not step the heads at the full
stepping rate of most PCs, so the stepping rate was set slightly slower
in the BIOS. Trouble was, the metal band type drive was designed for full
speed, and was very noisy when seeking at the slower speed. I wrote a small
driver that loaded (and unloaded again) during boot to reset the step speed
on machines with the faster drives. The drives looked identical externally,
you had to look in the slot or remove them from the case to see the difference.
PN 2684331 9.6v, 1.8AH
There were some guys on the VM 5140
Forum who talked about how to cut the battery pack apart with a Dremel
and replace the cells with industry >C cells. There is also a fuse in there.
From Don Hills
I was one of those guys. If you
couldn't get the "sub C" cells, the trick was to use standard C size cells
and duct tape them into a pack the same shape as the original. This "naked"
pack fitted in the same space as the original pack-plus-case. The battery
compartment was all plastic so the new pack was well protected.
As for the power supply, as I said in an earlier post there
was a US-only 110V "wall wart" that was only powerful enough to charge
the battery when the system wasn't running. There was also a universal
(100 to 240 volts) power "brick" much like those used on modern laptops,
that provided enough power (15 volts DC, 2.7 amps) to run the system and
all accessories while charging the battery.
The plug is the type that has a metal outer barrel as one contact and
a metal-lined hole down the middle (Center positive) that is the
other contact. Size: now pay attention here. 5.5 mm external diameter,
2.5 mm internal diameter. They also come in 2.1 mm internal diameter, so
the wrong one.
BATTERY CHARGER (#4060):
A 110-volt input feature designed to be used to charge the internal
batteries of the system. It does not provide sufficient power output
to allow system operation while the batteries are being charged
AUTOMOBILE POWER ADAPTER (#4065):
Designed to charge the system battery while allowing simultaneous use
of the system unit. The adapter attaches to the system unit and plugs
into the cigarette lighter outlet in a vehicle with a 12 volt negative-ground
Opening the 5140
From Don Hills (hanging
on to the undeside of the world and typing with the other....)
Open the battery compartment door and remove the battery. This is important,
as many parts of the machine such as the memory chips are permanently powered
so long as the battery is charged. The battery catch is on the bottom of
the plug (like a modular phone plug).
Open the display by pressing the two small grey buttons under the carrying
handle at the front right and left corners of the case. If you don't use
the catches, you might snap off one of the small retaining catches on the
LCD screen bezel. Pivot the display backwards until it is just past vertical.
Press on the front bottom (notice the neat-o vertical serrations?) of the
plastic plate covering the front of the display's "neck" until the plate
pivots away from the neck, then lift the display up (wiggle it slightly
side-to-side). This feature is why it's called the "Convertible".
Undo the 4 screws on the rear of the case. Lift and remove the rear
(non pivoting) part of the top cover.
Pull the grey carrying handle forward, exposing 2 small slots in the
case. Use a small screwdriver or coin to press inside the slots while lifting
up on the front of the keyboard. Be careful not to damage the foil cable.
Don't try unplugging it yet, just move it forwards and lay it on the extended
Note that the keyboard pivots on two small hinges at the front of the
Undo the 4 screws holding the diskette drives in and pull the drives
out. Thumb in the diskette slot, fingers underneath is the best grip. Note
that the floppy drive bezels have catches that fasten them to the drives.
They are not loose!
Reach in through the diskette drive bays with one hand and through the
opening at the rear with the other, and unclip the diskette drive plugs
from the clips on the underside of the (pivoting) top cover.
Lift the rear of the pivoting top cover and slide it forwards until
the pivot pin at the front disengages from the slot it slides in and lift
the cover up and away, unplugging the foil cable to the LCD socket as you
You can now unplug the keyboard cable.
Reassembly is the reverse of the above, just 3 tricks:
When screwing the diskette drives back in place, BE EXTREMELY GENTLE.
The screws must not be tightened too much- you will crack the drive front
plates and/or break the plastic pillars that the screws go into. THEY
ARE VERY FRAGILE. (Ed. They were cracked on mine)
I found that getting the LCD unit back on was interesting. Note that
the LCD swings on a "trapeeze" that has a metal pin going through it. Note
the two ptllars that come up on each side of the floppy and LCD headers.
Notice the arc made by the top of those pillars. See the groove? Notice
that the open end is toward the front.
What I did- lower the LCD neck to about halfway forward.
This lowers the cross-pin. Looking from the back, directly over the battery
well, you can see the shaft AND the grooves. Now you can actually SEE how
to position the top so the shaft will slide into the grooves.
When replacing the keyboard in its well, make sure the edge nearest
the diskette drives sits on (not under) the small ledges moulded in the
front plates of the diskette drives. These ledges lift the keyboard to
typing position when the case is opened. If you get it wrong you may break
when you try to close the case. The front corners of the keyboard
have little pivots that mate with the front of the bottom case. I had ot
push down lightly to make them "snap" in place.
As for piggyback accessories, there were several. They were known as
"slices", because they were the same profile as the back of the machine
and when clipped on looked like an extension of the machine.
A few additions to your page:
There was no way of powering the system off completely without removing
the battery. Some parts of the system, including the memory and much of
the planar, were continuously powered. Being static CMOS logic, they consumed
negligible power when not being clocked. The battery would hold the memory
(and run the clock, there was no separate clock battery) for a couple of
weeks. There was no suitable CMOS diskette controller chip so it used
a standard NEC 765. This was power hungry so was actually powered off when
not in use- the BIOS saved and loaded the controller's state between drive
accesses. I've got a lot more somewhere, including info gleaned from conversations
with the actual developers, and the full IBM Tech Ref and
Hardware Maintenance Manuals.
5140 System Unit Standard Features:
o Complementary Metal Oxide Semiconductor (CMOS) 80C88
o Two 32Kb CMOS ROMs containing:
- Power-on self-test of system components
- Basic Input Output System (BIOS) support
- BASIC language interpreter
o 256Kb CMOS RAM (expandable to 512Kb)
o Two 3.5-inch 720Kb (formatted) diskette drives
o 80-column x 25-line detachable LCD panel (graphics modes:
640 x 200 and 320 x 200)
o LCD controller
o 16Kb RAM display buffer
o 8Kb LCD font RAM
5140 System Unit Options:
o 128Kb Memory Card (#4005)
o Printer (#4010)
o Serial/Parallel Adapter (#4015)
o CRT Display Adapter (#4020)
o Internal Modem (#4025)
o Printer Cable (#4055)
o Battery Charger (#4060)
o Automobile Power Adapter (#4065)
o IBM 5144 PC Convertible Monochrome Display Model 1
o IBM 5145 PC Convertible Color Display Model 1
The 5140 is available in two models.
The model 2 is equipped with a CMOS 80C88 microprocessor, 64Kb ROM, 256Kb
RAM, an 80-column by 25-line detachable liquid crystal display, two 3.5-inch
diskette drives, a 78-key keyboard, an AC adapter, and a battery pack.
Also included are an Application Selector, SystemApps, Tools, Exploring
the IBM PC Convertible, and Diagnostics.
The model 22 is the same as the
model 2 with Diagnostics only. Both systems can be expanded to a maximum
of 512Kb RAM via 128Kb RAM memory card features, and may include an asynchronous
modem in the system unit.
The IBM PC Convertible Model 003
with a Backlit LCD has internal illumination, which means it can be used
in low-light conditions. Battery life is dependent on the setting
brightness control. The Backlit LCD works on all PC Convertible
models by plugging it into the LCD assembly, in place of the current screen,
and installing the new power supply. A new power supply is packaged
with the Backlit LCD Option Kit.
At the back of each system unit
is an extendable bus interface. This 72-pin connector allows any
or all of the following options to attach to the base unit: Printer, Serial/Parallel
Adapter, and CRT Display Adapter. Each of these features is powered from
the system unit. The CRT Display Adapter operates only when the system
is powered from a standard AC Adapter. A separate CRT display or television
set attached via the CRT Display Adapter requires a separate AC power source.
Each system unit is furnished
with a detachable liquid crystal display (LCD). When latched in its closed
position, it forms the cover for the keyboard and diskette drives. The
LCD is attached via a "quick disconnect" connector, which affords easy
removal so that the 5140 System Unit may be placed below an optional IBM
5144 PC Convertible Monochrome Display or an optional IBM 5145 PC Convertible
128KB MEMORY CARD (#4005):
Expands the base memory of the system unit. Maximum: Two, for
a system unit total of 512Kb.
Oh? I have a 5140 that had four memory cards in it. Go figure. The
case has catches molded in for four of the memory cards.
From Don Hills
System memory was 640 KB maximum, not 512 KB. There were
256 KB as well as 128 KB memory cards. Any combination could be used up
to 640 KB. 256 KB cards were rare, what several people did was build a
short ribbon cable to extend the last card's end connector to another 128KB
card which they laid on top of the others under the keyboard. Space was
too tight for my liking, so in my machine I actually ran the ribbon cable
through to the modem slot and put the 5th card there. One of my later machines
had 256 KB cards. They were easily recognisble as they had fewer (but higher
capacity) chips than the 128 KB cards.
Attaches to the back of the system unit, or to an optional printer
attachment cable for adjacent printer operation. It is an intelligent microprocessor-based,
40 cps (burst rate) serial, non-impact dot matrix design capable of low
power operation. It draws its power and control from the system unit.
Standard ASCII 96-character, upper-case and lower-case character sets are
using a high-resolution, 24-element print head. An all-points-addressable
(APA) print mode for graphics is also provided. Near-letter-quality printing
can be accomplished using either a thermal transfer ribbon on smooth (60
Sheffield units, maximum) paper, or no ribbon on heat-sensitive thermal
paper. Draft-quality printing may be achieved using the thermal transfer
ribbon on IBM Multi-System Paper (P/N 7034548) or equivalent.
SERIAL/PARALLEL ADAPTER (#4015):
Attaches to the back of the system unit, Printer (#4010), or another
feature module that might be
attached to the back of the system unit. The adapter provides an RS-232C
asynchronous communications interface and a parallel printer interface
that are compatible with the IBM Personal Computer Asynchronous Communications
Adapter and the IBM Personal Computer
Parallel Printer Adapter. Looks like this
CRT DISPLAY ADAPTER (#4020):
Attaches to the back of the system unit, Printer (#4010), or other
feature module attached to the back of the system unit. It allows the user
the option of connecting a separate CRT display to the system. The optional
5144 PC Convertible Monochrome Display or 5145 PC Convertible Color Display
may be attached via this adapter. Through the use of optional connectors
or cables, the CRT Display Adapter (#4020) also allows the attachment of
the IBM 4863 PCjr Color Display, IBM 5153 Color Display, or a standard
From Don Hills
The original systems had a first generation LCD display-
my first machine came with one. These were grey and low contrast. They
were upgraded with a supertwist LCD (sort of green/navy blue) that had
much better contrast. My first machine came bundled with this upgrade which
I performed myself. I only ever saw one system with the backlit LCD. It
used an electroluminescent
panel rather than a fluorescent tube and diffuser. They fell out of
favour because they couldn't produce as much light as a tube. The backlit
LCD was OK in very poor light conditions, but in normal room lighting or
sunlight you were much better off with the standard supertwist. I used
to sit up in bed writing code (DOS device drivers in ASM, for example)
with my machine. I had a small lamp mounted on the wall behind me that
shone at just the right angle for good visibility. The display characters
were large, and it was easy to load different fonts into the font memory
until you found one you liked.
INTERNAL MODEM (#4025):
Provides the user the capability to communicate with other compatible
units/systems over existing telephone lines. It uses modulation methods
and frequency tolerances equivalent to either Bell 212A (1,200 baud) in
high-speed mode or Bell 103A (300 baud) in low-speed mode. It is offered
as a complete assembly consisting of two cards connected by a cable. The
entire assembly is installed in the system unit.
IBM 5140 AP Internal Modem Connector Pinout
I/O Pin Signal Name
I / O
01 + Adress/Data Bit 0
02 + Adress/Data Bit 1
03 + Adress/Data Bit 2
04 + Adress/Data Bit 3
05 + Adress/Data Bit 4
06 + Adress/Data Bit 5
07 + Adress/Data Bit 6
08 + Adress/Data Bit 7
09 + Adress Bit 8
10 + Adress Bit 9
11 + Interupt Request 4
12 - I/O Read
13 + Reset
14 - Data Enable
16 + Adress Latch Enable
18 + Adress Enable
20 + 12 VDC
25 - 13 VDC
27 - I/O Write
28 + 5 VDC
30 + High Z
PRINTER CABLE (#4055):
A cabling accessory 22 inches (0.6 meter) in length with a custom 72-pin
system-type connector attached to each end. It provides the user the option
of operating the Printer (#4010) immediately adjacent to (that is, physically
detached from) the system unit, to provide flexibility of placement for
ease-of-use and visibility.
Mad Max has one of these, looks like THIS
IBM 5144 PC CONVERTIBLE MONOCHROME DISPLAY
The 5144 Display is a 9-inch (measured
diagonally) composite video display that is attached to the system unit
via the CRT Display Adapter. The display stand, an AC power cord, and a
signal cable that connects the 5144 to the CRT Display Adapter are provided
with the 5144. Character box size is 8 x 8 pels. Text modes are 80
x 25 and 40 x 25. Graphics modes are 640 x 200 and 320 x 200.
IBM 5145 PC CONVERTIBLE COLOR DISPLAY MODEL
The 5145 is a 13-inch (measured
diagonally) color display that displays in medium resolution (320 x 200).
It is designed for those customers whose application requirements will
be satisfied by that resolution. It is attached to the system unit via
the CRT Display Adapter (#4020). The display stand, an AC power cord,
and a signal cable that connects the 5145 to the CRT Display Adapter are
provided with the 5145. The display includes a speaker for external
audio output. The 5145 will display business and graphics data in 40 x
25 character mode. In 80 x 25 character mode, the 5145 can be used for
word processing and text applications.
CARRYING CASES: Two soft-sided carrying cases are offered for the IBM
PC Convertible. The standard model (#4090) will accommodate the system
unit, system-attached printer, various accessories, and supplies.
The system unit and printer can be operated from within the case.
The compact model (#4095) may be carried by hand, worn over the shoulder,
or carried backpack style. This model holds the system unit in the main
compartment and has an expandable pocket
where the printer, accessories, and paper or a notebook may be stored.
o IBM 5153 Color Display
o IBM PCjr Adapter Cable for the IBM Color Display (#0021)
o IBM 4863 PCjr Color Display
o IBM PCjr Connector for TV (#0020)
o IBM Communications Adapter Cable (#2067)
o IBM Proprinter (#4201)
o IBM Graphics Printer
o IBM 3708 Network Control Unit
o IBM 3710 Communication Adapter
o IBM Personal Computer Printer Cable
o IBM 5841 Modem - 1200 bps
All IBM Personal Computer, IBM
PCjr, IBM Personal Computer XT, IBM Personal Computer AT, or IBM Portable
Personal Computer options, adapters, and devices not specifically listed
above have not been tested on the IBM PC Convertible System and are not
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