5140 - PC Convertible

5140start_v100.zip IBM PC Convertible Start-Up Diskette v1.00 (31 Oct 1985, 6280631) [P]
5140start_v101.zip IBM PC Convertible Start-Up Diskette v1.01 (18 Mar 1986, 59X9546) [P]
5140start_v102.zip IBM PC Convertible Start-Up Diskette v1.02 (01 May 1986, 74X9774) [P]
5140start_v104.zip IBM PC Convertible Start-Up Diskette v1.03 (20 Jun 1986, 84X0107) [P]
   Zipped images. All disks imaged by David Beem.
5140star.exe IBM PC Convertible Start-Up Diskette v1.01 (self-extracting executable)
   Produces the same disk as 5140start_v101 above.
pccadv11.zip PS/1 Advanced Diagnostics Diskette (zipped image)

186-049 5140 Models 2/22, 5144 Mono Display 1, 5145 Color Display 1
187-140 5140 Model 003 And Backlit LCD Option Kit
187-006 New Special Features And Functions For 5140 Models 002 / 022

PC Convertible Technical Reference Volume 1, Feb 1986 (6280655)
PC Convertible Technical Reference Volume 2, Feb 1986 (55X8817)
PC Convertible Hardware Maintenance and Service, Feb 1986 (6280646) (thx Joe Bossalini)

Low-res IBM 5140 Convertible photos (MAD Max)
IBM 5140 Convertible photos (oldcrap.org)
IBM PC Convertible (5140) Battery Pack "DIY"

5140 Memory (memory cards types & pinout)
5140 Video (LCD displays, CRT adapter)

System Description
5140 Planar
Floppy Drive
Battery Pack
   Battery Charger
   Automobile Power Adapter
5140 Printer
Serial-Parallel Adapter
Internal Modem
   Internal Modem Pinout
   Internal Modem Board
Speech Adapter
Opening the 5140
Carrying Case

System Description

The 5140 is available in two models. The Model 2 is equipped with a CMOS 80C88 microprocessor, 64 KB ROM, 256 KB 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 512 KB RAM via 128 KB RAM memory card features, and may include an asynchronous modem in the system unit. The Model 003 has a backlit LCD and uses 256K memory cards.

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.

5140 System Unit Options

Optional Displays

Other Supported Options

  • IBM 5153 Color Display 183-002 Color Display, 5153
  • IBM PCjr Adapter Cable for the IBM Color Display (#0021)
  • IBM 4863 PCjr Color Display
  • IBM PCjr Connector for TV (#0020)
  • IBM Communications Adapter Cable (#2067)
  • IBM Proprinter (#4201)
  • IBM Graphics Printer
  • IBM 3708 Network Control Unit
  • IBM 3710 Communication Adapter
  • IBM Personal Computer Printer Cable
  • 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 supported.

DOS 3.2 or higher is required. (to support the 720K floppy)

5140 Planar [P] [P] [P]

No silkscreen, no reference designators, single-side load, all parts surface mounted (including the through-hole components!).

6453806 Interrupt, KB, Audio, system clock, I/O controller
6453807 DMA Controller
6487157 Floppy, Printer, system timer
6487158 LCD Controller
SRM2064M15 LCD Controller RAM
30-pin socket Modem Connector
Memory header More info HERE

Extendable Bus Interface

>Don, you mentioned that the 72 pin connector is ISA, but multiplexed.

Difficult. I looked at hacking ISA bus cards onto the Convertible bus. The main problem is that the address and data lines are multiplexed to get it all on the connector. You need extra logic to separate the address and data lines. I visualise a CRT slice (in this part of the world, they were cheaper and more common than the serial/parallel slice), with the CGA logic removed, and a slot in the top of the slice with an ISA riser sticking out. If you have the upgraded power supply (originally released with the backlit LCD option, but standard in later production), you should be able to run at least 2 ISA adapters if they aren't power hogs. Anyone got the schematic diagrams for the CGA slice?

Floppy Drive

3.5" 720K Toshiba 4452A0P11 with a 34-pin edgecard connector. Both drives are jumpered DS1.
3.5" 720K ALPS DFL413C02B, 34-pin edgecard. There are two jumpers on the top- SW1 (right rear corner) is jumpered "1", J1 (center-left front) is jumpered "B-C".

Floppy bezel snaps on drive case. I have used an 8580 cardedge floppy with the big button- slipped right in, bezel snapped right on (now to figure out how to get 5140 to recognize 1.44!). I see no P/N or FRU on it.

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.

Battery Pack P/N 2684331

Rating: 9.6 V, 1.8 Ah

Additional info about the battery pack and how to rebuild it can be found HERE.

From Gfretwell:
   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. Use Standard charge rate cells.

Consider standard C cells (with tabs) instead of sub-C, if they are cheaper yet. The only reason for sub-C cells is that they will fit back in the battery case. I used standard C cells (not even solder tabs, but I am good at soldering).

Of course they did not fit in the case, but I wired them up in the same physical pattern to the old cells, re-using the connector and thermal fuse from the old battery. Then I placed strips of cardboard where required between the cell ends to stop them shorting, sandwiched the cells between two sheets of cardboard cut using the old case as a template, and bound the whole lot in plastic insulation tape.

This package looked untidy, but fit just fine in the battery compartment. Since the battery compartment is a complete plastic box in its own right, the original battery pack casing is not essential.

Open the pack with a hammer and chisel. Clamp the pack on its side lightly in a vise with a piece of wood under it for support. Or, take a piece of scrap lumber and nail 2 short bits of 2x4 to it spaced so as to snugly hold the pack on its side. Apply chisel to the case join and tap a little harder each time until it cracks. Start at a corner and work around the pack.

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" (P/N 2684292) 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 don't get 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 electrical system.

5140 Printer (#4010)

Attaches to the back of the system unit, or to an optional printer attachment cable for adjacent printer operation. It is an intelligent CPU-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 printed using a high-resolution, 24-element print head. An all-points-addressable (APA) print mode for graphics is also provided. NLQ 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.

Printer Controls

There are three controls- A slide potentiometer on the left is for Density, left is light, right is dark. A two position switch in the middle, left is Off-Line, right is On-Line. A button is on the right for Line Feed. There is a blue lever on the left corner for clamping the guide against the roller. A paper advance wheel is on the right.

Detach Printer

Open printer cover. Look on the left side of the printer at the front corner of the smoked plastic cover. Notice the well with the silver loop. Lift up and pivot it out. This unlatches the left side, and the right side is just a pivot. Twist off the slice, pivoting it to the right.

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.

Serial/Parallel Adapter (#4015)

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.

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.

Internal Modem Port Board Racal Vadic., FCC ID ANO96M4025

J3 Modem port
J4 Dummy port
M1 ZP 94008-022
M3 Motorola 4N35Q8647
P1 30-pin header to sysboard
P2 20-pin header to Modem Board

IBM 5140 AP Internal Modem Connector Pinout

PinSignal NameDir PinSignal NameDir
01Address/Data Bit 0I/O 16Address Latch EnableI
02Address/Data Bit 1I/O 17Ground
03Address/Data Bit 2I/O 18Address EnableI
04Address/Data Bit 3I/O 19Ground
05Address/Data Bit 4I/O 20+12 VDC
06Address/Data Bit 5I/O 21Ground
07Address/Data Bit 6I/O 22Ground
08Address/Data Bit 7I/O 23Ground
09Address Bit 8I 24Ground
10Address Bit 9I 25-13 VDC
11Interrupt Request 4O 26Ground
12-I/O ReadI 27-I/O WriteI
13ResetI 28+5 VDC
14-Data EnableI 29Ground
15Ground 30High ZI

Internal Modem Board

J1 4-pin header, pins snipped
J2 20-pin header to Modem port
M2 M83C154-29
M4 ZP 9410-015
M8 ZP 2120CP
Y1 11.0592 MHz xtal
Y2 4.0320 MHz xtal
Y3 3.579545 MHz xtal

The main modem board slides into place on top of the battery pack's enclosure.

Speech Adapter (#4040)


The speech adapter is functionally equivalent to the IBM PCjr Speech Adapter.

  • CMOS ROM has 196 stored vocabulary words
  • Supports two types of speech reproduction:
    • CVSD (Continuously Variable Slope Delta modulation)
    • LPC (Linear Predictive Coding)
  • Microphone interface
  • Audio output

Opening the 5140

From Don Hills:
   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 handle.
Note that the keyboard pivots on two small hinges at the front of the lower case.

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 do so.

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)

From Us, the god-Emperor of Microchannel:
   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 pillars 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.

Back to Don:
   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 things 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 to 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.

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.

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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