IBM 5151: Difference between revisions

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{Infobox computer peripheral | name = IBM Monochrome Display | image = | caption = IBM monitors, left to right: 5151 monochrome, 5153 colour, 5154 Enhanced Color Display | manufacturer = IBM | type = TTL monochrome CRT monitor | release_date = 1981 (with the original IBM PC) | interface = TTL digital, 9-pin D-shell (driven by the IBM Monochrome Display Adapter) | compatible = IBM PC (5150), IBM PC XT (5160), IBM PC AT (5170), MDA- and Hercules-compatible systems | dimensions = 280 mm H × 380 mm L × 350 mm D | weight = 7.9 kg (17.3 lb) | model = 5151 }

The IBM 5151, which IBM called simply the IBM Monochrome Display, is the green-phosphor TTL monitor sold with the original IBM PC (5150) when it was ordered with the IBM Monochrome Display Adapter (MDA). It displays 80 × 25 text only — it has no graphics capability — but the MDA's large 9 × 14 character box gives an image of 720 by 350 addressable dots, which is why MDA text is visibly sharper than CGA text.

Display Characteristics

IBM's own figures:^[1]

CRT: 28.3 cm (11.5 in) diagonal, 90° deflection.
Phosphor: P39, high persistence, green. Long persistence suppresses flicker at the 5151's low refresh rate, at the cost of smearing on moving content.
Screen surface: etched to reduce glare.
Presentation: 80 characters wide by 25 rows deep, each character defined in a 14 PEL high by 9 PEL wide matrix.
Vertical drive: screen refreshed at 50 Hz, with 350 lines of vertical resolution and 720 lines of horizontal resolution.
Horizontal drive: positive-level, TTL-compatible, at 18.432 kHz.
Video bandwidth: 16.257 MHz maximum at −3 dB.
Heat output: 325 BTU/hr. Cables: 0.914 m power, 1.22 m signal.

Measured at the adapter, the MDA horizontal sync is an 8 µs positive-going pulse every 54.3 µs and the vertical sync is an 850 µs negative-going pulse every 20 ms.^[2]

The 5151 will not work with a CGA card: CGA runs its horizontal scan at 15.75 kHz, well outside the 5151's fixed 18.432 kHz.^[2]

Power

The 5151 has no mains cord of its own. It takes both its signal and its power from the system unit: the signal cable comes from the display adapter, and a second cable takes ac power from a non-standard switched socket on the rear of the PC's power supply, so that the system unit's power switch controls the display.^[1] That outlet can supply a maximum of 0.75 A and IBM states it is intended only for this display.^[3]

Two models were made, a 110 Vac model and a 220/240 Vac model, and IBM's Options and Adapters section carries a separate full schematic for each.^[1]

Input Connector

A 9-pin D-shell at standard TTL levels — 0.0 to 0.6 Vdc at down level, +2.4 to 3.5 Vdc at up level.^[4]

**MDA / 5151 9-pin connector**
Pin	Signal
1	Ground
2	Ground
3, 4, 5	Not used
6	+ Intensity
7	+ Video
8	+ Horizontal sync
9	− Vertical sync

Pins 3, 4 and 5 being physically absent from the plug is normal, not damage — they are unused in the MDA standard.^[5]

The display's three brightness levels (off, normal, bright) come from the combination of the Video and Intensity lines, not from an analogue video level.^[4]

Common Faults

Stiff brightness and contrast knobs. Known behaviour on a healthy 5151, and probably deliberate. Not a fault.^[5]
Stable raster with the brightness turned up, but no characters. On a 5151 specifically, a stable raster proves the monitor is receiving correct horizontal and vertical sync from the MDA card. Work through: contrast set too low; a faulty MDA card that generates sync but no video; an open video wire in the cable; a poor connection on pin 7 at the plug; then the video path inside the monitor. IC201, an SN7406A, has been reported failed by more than one owner.^[5]
No display at all, not even a raster. The 5151 needs an incoming horizontal sync signal from a working, initialised MDA card to produce any raster at all. Before condemning the monitor, check that the card is present, seated and initialised — motherboard switch settings that select EGA instead of MDA will leave it uninitialised.^[5]
Full or partial vertical collapse. A known symptom with published circuit and waveform references.^[5]
Bright spot or line when switching off. Known behaviour, not a fault.^[5]
Dim or shrunken raster, or geometry that drifts as the set warms up. Points at ageing electrolytics on the analogue board. See Capacitor Failure Symptoms.

A self-inflicted fault worth knowing about

Because of the way the 5151 is designed, an improper horizontal sync signal can damage it — and software alone is enough to produce that situation by reprogramming the 6845 on the MDA card outside MDA timings.^[5] Do not run 6845 timing experiments, Hercules-mode software or untested demos against a 5151 you care about.

CRT Safety

The 5151's CRT retains a lethal anode charge after the set is switched off and unplugged, and its mains-derived circuitry sits at line potential while it is running. Discharge the tube before working inside it — see CRT Discharge Procedure.

References

↑ ^1.0 ^1.1 ^1.2 IBM, IBM Monochrome Display, Options and Adapters section, Personal Computer Hardware Reference Library — hosted on this wiki as File:IBM Options and Adapters - IBM Monochrome Display (5151).pdf. "Description" and "Specifications": the two-cable arrangement with power taken from the system unit, the 28.3 cm (11.5 in) diagonal 90-degree-deflection CRT, P39 high-persistence green phosphor with an etched anti-glare surface, 80 characters by 25 rows in a 14 PEL high by 9 PEL wide matrix, maximum video bandwidth 16.257 MHz at −3 dB, 50 Hz vertical refresh with 350 lines vertical and 720 lines horizontal resolution, positive-level TTL horizontal drive at 18.432 kHz, and the physical specifications quoted here. Also documented here as IBM Options and Adapters - IBM Monochrome Display.
↑ ^2.0 ^2.1 IBM: MDA / CGA / EGA, minuszerodegrees.net. Source for the side-by-side 9-pin assignments and for the measured sync pulse shapes: MDA, an 8 us positive-going horizontal pulse every 54.3 us and an 850 us negative-going vertical pulse every 20 ms; CGA, a 4 us positive-going horizontal pulse every 63.7 us and a 190 us positive-going vertical pulse every 16.7 ms.
↑ IBM, IBM 5150 Technical Reference — hosted on this wiki as File:IBM PC 5150 Technical Reference.pdf and documented as IBM PC 5150 Technical Reference. Section 1 "System Board" for the ROM and RAM subsystems; Section 3 "Power Supply", pages 3-3 to 3-6, for the 63.5 W continuous rating, the four dc outputs and their load and regulation figures, the −5 V dynamic-memory bias role, the switched 0.75 A ac outlet provided only for the IBM Monochrome Display, the overvoltage and overcurrent behaviour, the five-second minimum off time and the under- and over-voltage sense levels; Section 4 "Keyboard" for the capacitive keyboard, its Intel 8048, the permanently attached coiled five-wire cable, the 83-key layout, the scan-code protocol and the keyboard's own power-on self test.
↑ ^4.0 ^4.1 IBM, IBM Monochrome Display and Printer Adapter, Options and Adapters section, Personal Computer Hardware Reference Library — hosted on this wiki as File:IBM Options and Adapters - IBM Monochrome Display and Printer Adapter.pdf. Source for the Motorola 6845 CRT controller, the 4 KB display buffer with no parity, the two-bytes-in-553 ns fetch giving 1.8 MB/s, the 8 KB character generator holding 256 codes, the 9 PEL by 14 PEL character box carrying a 7 PEL by 9 PEL character, the 18 kHz monitor requirement, the statement that the adapter does not support a light pen with a P39-phosphor display, the register map, the 9-pin connector pin assignments and TTL signal levels, and the printer-adapter half with its 12 latched outputs and 5 steady-state inputs. Also documented here as IBM Options and Adapters - IBM Monochrome Display and Printer Adapter.
↑ ^5.0 ^5.1 ^5.2 ^5.3 ^5.4 ^5.5 ^5.6 IBM 5151 — Known Problems/Issues, minuszerodegrees.net. Source for the stiff brightness and contrast controls being normal, the raster-but-no-video diagnosis, the reported IC201 (SN7406A) failures, the vertical collapse and switch-off bright line notes, the statement that pins 3, 4 and 5 are absent from the connector by design, and the warning that an improper horizontal sync signal can damage the 5151.

Related Pages

IBM Monochrome Display Adapter — the adapter that drives the 5151
IBM 5153 — the colour equivalent
IBM PC (5150) · IBM PC XT (5160) · IBM PC AT (5170)
IBM Options and Adapters - IBM Monochrome Display — IBM's own specification, hosted here
CRT Discharge Procedure · Capacitor Failure Symptoms

[oa5151-1] 1.0 ^1.1 ^1.2 IBM, IBM Monochrome Display, Options and Adapters section, Personal Computer Hardware Reference Library — hosted on this wiki as File:IBM Options and Adapters - IBM Monochrome Display (5151).pdf. "Description" and "Specifications": the two-cable arrangement with power taken from the system unit, the 28.3 cm (11.5 in) diagonal 90-degree-deflection CRT, P39 high-persistence green phosphor with an etched anti-glare surface, 80 characters by 25 rows in a 14 PEL high by 9 PEL wide matrix, maximum video bandwidth 16.257 MHz at −3 dB, 50 Hz vertical refresh with 350 lines vertical and 720 lines horizontal resolution, positive-level TTL horizontal drive at 18.432 kHz, and the physical specifications quoted here. Also documented here as IBM Options and Adapters - IBM Monochrome Display.

[mzpins-2] 2.0 ^2.1 IBM: MDA / CGA / EGA, minuszerodegrees.net. Source for the side-by-side 9-pin assignments and for the measured sync pulse shapes: MDA, an 8 us positive-going horizontal pulse every 54.3 us and an 850 us negative-going vertical pulse every 20 ms; CGA, a 4 us positive-going horizontal pulse every 63.7 us and a 190 us positive-going vertical pulse every 16.7 ms.

[tr5150-3] IBM, IBM 5150 Technical Reference — hosted on this wiki as File:IBM PC 5150 Technical Reference.pdf and documented as IBM PC 5150 Technical Reference. Section 1 "System Board" for the ROM and RAM subsystems; Section 3 "Power Supply", pages 3-3 to 3-6, for the 63.5 W continuous rating, the four dc outputs and their load and regulation figures, the −5 V dynamic-memory bias role, the switched 0.75 A ac outlet provided only for the IBM Monochrome Display, the overvoltage and overcurrent behaviour, the five-second minimum off time and the under- and over-voltage sense levels; Section 4 "Keyboard" for the capacitive keyboard, its Intel 8048, the permanently attached coiled five-wire cable, the 83-key layout, the scan-code protocol and the keyboard's own power-on self test.

[oamda-4] 4.0 ^4.1 IBM, IBM Monochrome Display and Printer Adapter, Options and Adapters section, Personal Computer Hardware Reference Library — hosted on this wiki as File:IBM Options and Adapters - IBM Monochrome Display and Printer Adapter.pdf. Source for the Motorola 6845 CRT controller, the 4 KB display buffer with no parity, the two-bytes-in-553 ns fetch giving 1.8 MB/s, the 8 KB character generator holding 256 codes, the 9 PEL by 14 PEL character box carrying a 7 PEL by 9 PEL character, the 18 kHz monitor requirement, the statement that the adapter does not support a light pen with a P39-phosphor display, the register map, the 9-pin connector pin assignments and TTL signal levels, and the printer-adapter half with its 12 latched outputs and 5 steady-state inputs. Also documented here as IBM Options and Adapters - IBM Monochrome Display and Printer Adapter.

[mz5151-5] 5.0 ^5.1 ^5.2 ^5.3 ^5.4 ^5.5 ^5.6 IBM 5151 — Known Problems/Issues, minuszerodegrees.net. Source for the stiff brightness and contrast controls being normal, the raster-but-no-video diagnosis, the reported IC201 (SN7406A) failures, the vertical collapse and switch-off bright line notes, the statement that pins 3, 4 and 5 are absent from the connector by design, and the warning that an improper horizontal sync signal can damage the 5151.

[1]

[2]

[3]

[4]

[5]

@@ Line 1: / Line 1: @@
-{{Infobox computer peripheral
+{Infobox computer peripheral
-| name          = IBM 5151 Personal Computer Display
+| name          = IBM Monochrome Display
 | image         = [[File:IBM 5151 5153 5154 monitors.jpg|260px]]
-| caption       = IBM monitors from left to right: 5151 monochrome, 5153 colour CGA, 5154 EGA
+| caption       = IBM monitors, left to right: 5151 monochrome, 5153 colour, 5154 Enhanced Color Display
 | manufacturer  = IBM
 | type          = TTL monochrome CRT monitor
 | release_date  = 1981 (with the original IBM PC)
-| interface     = TTL digital, 9-pin D-shell (paired with the [[IBM Monochrome Display Adapter]])
+| interface     = TTL digital, 9-pin D-shell (driven by the [[IBM Monochrome Display Adapter]])
-| compatible    = [[IBM PC (5150)]], [[IBM PC XT (5160)]], any MDA / Hercules-compatible system
+| compatible    = [[IBM PC (5150)]], [[IBM PC XT (5160)]], [[IBM PC AT (5170)]], MDA- and Hercules-compatible systems
-| dimensions    = 12" CRT (~11.5" diagonal viewable area)
+| dimensions    = 280 mm H &times; 380 mm L &times; 350 mm D
+| weight        = 7.9 kg (17.3 lb)
 | model         = 5151
-}}
+}
-The '''IBM 5151''' (the '''IBM Personal Computer Display''') is the 12-inch green-phosphor TTL monitor IBM shipped with the original [[IBM PC (5150)]] when it was paired with the [[IBM Monochrome Display Adapter]] (MDA). The 5151 displays 80×25 text only — it has no graphics capability — but produces a 720×350-pixel character image because the MDA generates a 9×14 dot character cell rather than the smaller cell used by the CGA.
+The '''IBM 5151''', which IBM called simply the '''IBM Monochrome Display''', is the green-phosphor TTL monitor sold with the original [[IBM PC (5150)]] when it was ordered with the [[IBM Monochrome Display Adapter]] (MDA). It displays 80&nbsp;&times;&nbsp;25 text only &mdash; it has no graphics capability &mdash; but the MDA's large 9&nbsp;&times;&nbsp;14 character box gives an image of 720 by 350 addressable dots, which is why MDA text is visibly sharper than [[IBM Color Graphics Adapter|CGA]] text.
 == Display Characteristics ==
-* '''Phosphor:''' P39 (long-persistence green); reduces flicker but smears on moving content.
+IBM's own figures:<ref name="oa5151">IBM, ''IBM Monochrome Display'', ''Options and Adapters'' section, Personal Computer Hardware Reference Library &mdash; hosted on this wiki as [[:File:IBM Options and Adapters - IBM Monochrome Display (5151).pdf]]. "Description" and "Specifications": the two-cable arrangement with power taken from the system unit, the 28.3 cm (11.5 in) diagonal 90-degree-deflection CRT, P39 high-persistence green phosphor with an etched anti-glare surface, 80 characters by 25 rows in a 14 PEL high by 9 PEL wide matrix, maximum video bandwidth 16.257 MHz at &minus;3 dB, 50 Hz vertical refresh with 350 lines vertical and 720 lines horizontal resolution, positive-level TTL horizontal drive at 18.432 kHz, and the physical specifications quoted here. Also documented here as [[IBM Options and Adapters - IBM Monochrome Display]].</ref>
-* '''Resolution:''' 720 × 350 pixels, addressed as 80 × 25 characters in a 9 × 14 dot cell.
-* '''Horizontal scan:''' 18.432 kHz.
-* '''Vertical scan:''' 50 Hz.
-* '''Brightness levels:''' three (off / normal / bright), encoded across the TTL video + intensity pair.
-* '''Anti-glare:''' etched front glass.
-The 5151 will '''not''' work with the [[IBM Color Graphics Adapter|CGA]], because CGA runs at 15.75 kHz horizontal — well below what the 5151's flyback can lock to.
+* '''CRT:''' 28.3 cm (11.5 in) diagonal, 90&deg; deflection.
+* '''Phosphor:''' P39, high persistence, green. Long persistence suppresses flicker at the 5151's low refresh rate, at the cost of smearing on moving content.
+* '''Screen surface:''' etched to reduce glare.
+* '''Presentation:''' 80 characters wide by 25 rows deep, each character defined in a 14 PEL high by 9 PEL wide matrix.
+* '''Vertical drive:''' screen refreshed at '''50 Hz''', with 350 lines of vertical resolution and 720 lines of horizontal resolution.
+* '''Horizontal drive:''' positive-level, TTL-compatible, at '''18.432 kHz'''.
+* '''Video bandwidth:''' 16.257 MHz maximum at &minus;3 dB.
+* '''Heat output:''' 325 BTU/hr. '''Cables:''' 0.914 m power, 1.22 m signal.
+Measured at the adapter, the MDA horizontal sync is an 8&nbsp;&micro;s positive-going pulse every 54.3&nbsp;&micro;s and the vertical sync is an 850&nbsp;&micro;s '''negative'''-going pulse every 20&nbsp;ms.<ref name="mzpins">[https://www.minuszerodegrees.net/mda_cga_ega/mda_cga_ega.htm IBM: MDA / CGA / EGA], minuszerodegrees.net. Source for the side-by-side 9-pin assignments and for the measured sync pulse shapes: MDA, an 8 us positive-going horizontal pulse every 54.3 us and an 850 us '''negative'''-going vertical pulse every 20 ms; CGA, a 4 us positive-going horizontal pulse every 63.7 us and a 190 us positive-going vertical pulse every 16.7 ms.</ref>
+The 5151 will '''not''' work with a [[IBM Color Graphics Adapter|CGA]] card: CGA runs its horizontal scan at 15.75 kHz, well outside the 5151's fixed 18.432 kHz.<ref name="mzpins" />
+== Power ==
+The 5151 has '''no mains cord of its own'''. It takes both its signal and its power from the system unit: the signal cable comes from the display adapter, and a second cable takes ac power from a non-standard switched socket on the rear of the PC's power supply, so that the system unit's power switch controls the display.<ref name="oa5151" /> That outlet can supply a maximum of 0.75 A and IBM states it is intended only for this display.<ref name="tr5150">IBM, ''IBM 5150 Technical Reference'' &mdash; hosted on this wiki as [[:File:IBM PC 5150 Technical Reference.pdf]] and documented as [[IBM PC 5150 Technical Reference]]. Section 1 "System Board" for the ROM and RAM subsystems; Section 3 "Power Supply", pages 3-3 to 3-6, for the 63.5 W continuous rating, the four dc outputs and their load and regulation figures, the &minus;5 V dynamic-memory bias role, the switched 0.75 A ac outlet provided only for the IBM Monochrome Display, the overvoltage and overcurrent behaviour, the five-second minimum off time and the under- and over-voltage sense levels; Section 4 "Keyboard" for the capacitive keyboard, its Intel 8048, the permanently attached coiled five-wire cable, the 83-key layout, the scan-code protocol and the keyboard's own power-on self test.</ref>
+Two models were made, a 110 Vac model and a 220/240 Vac model, and IBM's ''Options and Adapters'' section carries a separate full schematic for each.<ref name="oa5151" />
 == Input Connector ==
-A 9-pin D-shell, TTL-level signals.
+A 9-pin D-shell at standard TTL levels &mdash; 0.0 to 0.6 Vdc at down level, +2.4 to 3.5 Vdc at up level.<ref name="oamda">IBM, ''IBM Monochrome Display and Printer Adapter'', ''Options and Adapters'' section, Personal Computer Hardware Reference Library &mdash; hosted on this wiki as [[:File:IBM Options and Adapters - IBM Monochrome Display and Printer Adapter.pdf]]. Source for the Motorola 6845 CRT controller, the 4 KB display buffer with no parity, the two-bytes-in-553 ns fetch giving 1.8 MB/s, the 8 KB character generator holding 256 codes, the 9 PEL by 14 PEL character box carrying a 7 PEL by 9 PEL character, the 18 kHz monitor requirement, the statement that the adapter does not support a light pen with a P39-phosphor display, the register map, the 9-pin connector pin assignments and TTL signal levels, and the printer-adapter half with its 12 latched outputs and 5 steady-state inputs. Also documented here as [[IBM Options and Adapters - IBM Monochrome Display and Printer Adapter]].</ref>
-* '''Pins 1, 2:''' Ground
+<templatestyles src="Template:StyledTable/styles.css" />
-* '''Pin 7:''' Video
+{| class="wikitable styled-table" style="width:60%; text-align:center;"
-* '''Pin 8:''' Horizontal sync
+|+'''MDA / 5151 9-pin connector'''
-* '''Pin 9:''' Vertical sync
+! Pin !! Signal
+|-
+| 1 || Ground
+|-
+| 2 || Ground
+|-
+| 3, 4, 5 || Not used
+|-
+| 6 || + Intensity
+|-
+| 7 || + Video
+|-
+| 8 || + Horizontal sync
+|-
+| 9 || &minus; Vertical sync
+|}
-The 5151 derives its three brightness levels from the combination of the Video and Intensity lines on the [[IBM Monochrome Display Adapter|MDA]].
+'''Pins 3, 4 and 5 being physically absent from the plug is normal''', not damage &mdash; they are unused in the MDA standard.<ref name="mz5151">[https://www.minuszerodegrees.net/5151/problems/5151_known_problems_issues.htm IBM 5151 &mdash; Known Problems/Issues], minuszerodegrees.net. Source for the stiff brightness and contrast controls being normal, the raster-but-no-video diagnosis, the reported IC201 (SN7406A) failures, the vertical collapse and switch-off bright line notes, the statement that pins 3, 4 and 5 are absent from the connector by design, and the warning that an improper horizontal sync signal can damage the 5151.</ref>
+The display's three brightness levels (off, normal, bright) come from the combination of the Video and Intensity lines, not from an analogue video level.<ref name="oamda" />
 == Common Faults ==
-* '''Yoke or flyback whine''' — reflow flyback transformer joints.
+* '''Stiff brightness and contrast knobs.''' Known behaviour on a healthy 5151, and probably deliberate. Not a fault.<ref name="mz5151" />
-* '''Dim or shrunken raster''' — service the analog board electrolytics.
+* '''Stable raster with the brightness turned up, but no characters.''' On a 5151 specifically, a stable raster proves the monitor is receiving correct horizontal and vertical sync from the MDA card. Work through: contrast set too low; a faulty MDA card that generates sync but no video; an open video wire in the cable; a poor connection on pin 7 at the plug; then the video path inside the monitor. '''IC201, an SN7406A, has been reported failed by more than one owner.'''<ref name="mz5151" />
-* '''Flickering brightness''' — clean the DB-9 input contacts.
+* '''No display at all, not even a raster.''' The 5151 needs an incoming horizontal sync signal from a working, initialised MDA card to produce any raster at all. Before condemning the monitor, check that the card is present, seated and initialised &mdash; motherboard switch settings that select EGA instead of MDA will leave it uninitialised.<ref name="mz5151" />
-* '''No display, audible flyback''' — failed video amplifier transistor, or open filament on the CRT.
+* '''Full or partial vertical collapse.''' A known symptom with published circuit and waveform references.<ref name="mz5151" />
+* '''Bright spot or line when switching off.''' Known behaviour, not a fault.<ref name="mz5151" />
+* '''Dim or shrunken raster, or geometry that drifts as the set warms up.''' Points at ageing electrolytics on the analogue board. See [[Capacitor Failure Symptoms]].
+=== A self-inflicted fault worth knowing about ===
+Because of the way the 5151 is designed, '''an improper horizontal sync signal can damage it''' &mdash; and software alone is enough to produce that situation by reprogramming the 6845 on the MDA card outside MDA timings.<ref name="mz5151" /> Do not run 6845 timing experiments, Hercules-mode software or untested demos against a 5151 you care about.
 == CRT Safety ==
-The 5151's CRT retains a lethal anode charge. Discharge before opening — see [[CRT Discharge Procedure]].
+The 5151's CRT retains a lethal anode charge after the set is switched off and unplugged, and its mains-derived circuitry sits at line potential while it is running. Discharge the tube before working inside it &mdash; see [[CRT Discharge Procedure]].
 == References ==
-* [https://en.wikipedia.org/wiki/IBM_5151 IBM 5151 — Wikipedia].
+<references />
-* IBM, ''[https://minuszerodegrees.net/oa/OA%20-%20IBM%20Monochrome%20Display%20(5151).pdf IBM Monochrome Display (5151)]'' service documentation.
 == Related Pages ==
-* [[IBM PC (5150)]] — the system the 5151 was sold with
+* [[IBM Monochrome Display Adapter]] &mdash; the adapter that drives the 5151
-* [[IBM Monochrome Display Adapter]] — the adapter card that drives the 5151
+* [[IBM 5153]] &mdash; the colour equivalent
-* [[IBM 5153]] — the colour equivalent
+* [[IBM PC (5150)]] &middot; [[IBM PC XT (5160)]] &middot; [[IBM PC AT (5170)]]
-* [[CRT Discharge Procedure]]
+* [[IBM Options and Adapters - IBM Monochrome Display]] &mdash; IBM's own specification, hosted here
+* [[CRT Discharge Procedure]] &middot; [[Capacitor Failure Symptoms]]
+{{Navbox-IBMComputers|state=collapsed}}
 [[Category:IBM]]

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