Josh: New page: Duo 270c, specs from Apple SS and SP157, board, Sharp panel, upgrades

2026-10-02T08:37:22Z

New page: Duo 270c, specs from Apple SS and SP157, board, Sharp panel, upgrades

New page

{{Infobox computer
| name = PowerBook Duo 270c
| image = [[File:PowerBook Duo 270c (Bluedisk).jpg|260px|frameless]]
| caption = PowerBook Duo 270c with a third-party extended battery (Bluedisk, Wikimedia Commons, CC BY-SA 3.0)
| manufacturer = Apple Computer, Inc.
| type = Subnotebook computer
| release_date = 21 October 1993
| discontinued = 1 May 1994
| price = US$3,100
| cpu = Motorola 68030 at 33 MHz with 68882 FPU
| memory = 4 MB on the logic board; one Duo RAM card slot, to 32 MB
| rom = 1 MB
| storage = 240 MB 2.5-inch SCSI hard drive
| display = 9-inch colour active-matrix LCD, 640 × 480 at 256 colours or 640 × 400 at thousands of colours
| power = Type II NiMH battery; 24 V DC adapter
| dimensions = 1.5 × 10.9 × 8.5 in (H × W × D)
| weight = 4.8 lb (2.1 kg)
| os = System 7.1 to Mac OS 7.6.1
}}
The '''PowerBook Duo 270c''' is the first colour PowerBook Duo, introduced on 21 October 1993 alongside the [[PowerBook Duo 250]]. It has a 33 MHz 68030 with a 68882 floating-point unit on the logic board, the only one in the 68030 Duos, and a 9-inch colour active-matrix screen. It is thicker and heavier than the greyscale models, at 1.5 in and 4.8 lb.<ref name="sp157">Apple, [https://support.apple.com/kb/SP157 "Macintosh PowerBook Duo 270c: Technical Specifications"] (retrieved 2026-10-02). 68030 at 33 MHz; FPU 68882; 25 W, 1.04 A; Duo NiMH Type II battery; 4 MB on board, one Duo RAM slot, 4-32 MB; 640 × 400 at 16 bits, 640 × 480 at 8 bits; introduced 10/21/1993, discontinued 5/1/1994; Gestalt ID 77; 4.8 lb; 1.5 H × 10.9 W × 8.5 D in; System 7.1 with PowerBook Duo Enabler v1.0, supported to 7.6.1; 240 MB SCSI hard drive.</ref><ref name="ss">Apple Computer, ''PowerBook 200 Series'' Service Source, hosted here as [[:File:PowerBook Duo 200 Series Service Source.pdf]] (see [[PowerBook Duo 200 Series Service Source]]). PDF page numbers: processor and memory pp. 14-17; display p. 22; electrical pp. 24-25; physical p. 26; video symptom charts pp. 40-50; case bottom pp. 140-144; 270c/280c display cable pp. 167-176; inverter board pp. 177-181; brightness actuator pp. 182-186; speaker pp. 187-189; 270c upgrade pp. 212-215; 280/280c upgrade pp. 216-226; exploded view p. 266.</ref> It was replaced by the 68LC040-based [[PowerBook Duo 280|PowerBook Duo 280c]] in May 1994.<ref name="sp157" /><ref name="wp" />

== Specifications ==
<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:70%;"
|+ '''Apple's specifications'''<ref name="ss" /><ref name="sp157" />
! Item !! PowerBook Duo 270c
|-
| Processor || Motorola 68030, 33 MHz; Motorola 68882 FPU on the logic board
|-
| RAM || 4 MB soldered; one Duo RAM card of 4, 6, 8, 10, 12, 16 or 20 MB, to 32 MB, 70 ns<ref name="amg">Apple Computer, ''Apple Memory Guide'' (May 2000), hosted here as [[:File:Apple Memory Guide (May 2000).pdf]] (see [[Apple Memory Guide]]). PowerBook Duo 270c, PDF p. 110: 4 MB soldered DRAM; 32 MB maximum; Apple supplies 4 MB and 8 MB cards.</ref>
|-
| Display || 9-inch (229 mm) colour active-matrix LCD with CCFL backlight; 640 × 480 at 8 bits (256 colours) or 640 × 400 at 16 bits
|-
| Storage || 240 MB 2.5-inch SCSI hard drive
|-
| Main battery || NiMH Type II, 1.5 Ah; about 2 to 3 hours
|-
| Power adapter || 24 V DC, 1.04 A (25 W)
|-
| Size and weight || 1.5 in high; 4.8 lb (2.1 kg) with battery
|-
| Gestalt ID || 77
|}

Low End Mac gives the launch price as US$3,100 and lists a 24 MB maximum; Apple's own documents give 32 MB.<ref name="lem270c">Low End Mac, [https://lowendmac.com/1993/powerbook-duo-270c/ "PowerBook Duo 270c"] (retrieved 2026-10-02). Introduced 1993.10.21 at $3,100, discontinued 1994.05.01; 4 MB expandable to 24 MB; 640 × 480 at 8 bits and 640 × 400 at 16 bits, 89 ppi; 4.8 lb; power supply M7783; upgrade path Duo 280c. Secondary source.</ref><ref name="amg" /> Wikipedia states that 16-bit colour at 640 × 400 was a first for a notebook.<ref name="wp">Wikipedia, [https://en.wikipedia.org/wiki/PowerBook_Duo "PowerBook Duo"] (retrieved 2026-10-02). Duo 250 and 270c released October 1993; 270c display of 256 colours at 640 × 480 or 32,768 colours at 640 × 400; redesigned logic board with 68882 and 32 MB; Type II battery. Used for history only.</ref>

== Hardware ==
=== Logic board ===
The 270c has its own logic board, with the FPU and a different set of electrolytic capacitors from the 210/230/250 board: four 100 µF 35 V, one 100 µF 25 V, one 47 µF 35 V and one 33 µF 25 V, all surface-mount.<ref name="macdat270c">MacDat, [https://macdat.net/cap_reference/apple/powerbook/duo270c.html "PowerBook Duo 270c Capacitor Reference"] (retrieved 2026-10-02). Logic board: four 100 µF 35 V, one 100 µF 25 V, one 47 µF 35 V, one 33 µF 25 V; Sharp LQ9D041 LCD: three 100 µF 6 V, one 47 µF 16 V, six 47 µF 6 V, one 33 µF 10 V, two 22 µF 10 V, one 10 µF 25 V, one 10 µF 16 V; inverter: one 10 µF 35 V; early trackballs: one 10 µF 6.3 V; logic board photo by mitchW. Secondary source.</ref><ref name="mitch">68kMLA forum thread [https://68kmla.org/bb/threads/powerbook-duo-270c-restoration.38398/ "PowerBook Duo 270c Restoration"], m68k (July 2021) and mitchW (September 2023). Corroded 270c board with a burnt ceramic capacitor; mitchW's capacitor list with case sizes and height limits, the Sharp LQ9D041 panel list, and a leaking 10 µF 35 V capacitor on the inverter. Community repair report.</ref> mitchW's measurements of the footprints are 10 × 10 mm for the 100 µF 35 V parts, 8 × 8 mm for the 47 µF and the 100 µF 25 V, and 6 × 6 mm for the 33 µF, with all parts no taller than 10 to 11 mm.<ref name="mitch" /> In 2012 techknight, stripping a 270c with a broken screen, found these capacitors starting to leak. He identified the 35 V parts as the filter on the 24 V DC input and the others as the DC-DC converter filters.<ref name="tk">68kMLA forum thread [https://68kmla.org/bb/threads/notice-to-powerbook-duo-users.24829/ "Notice to Powerbook Duo Users!"], techknight and others, February-March 2012. Leaking electrolytics in the DC-DC circuit of a Duo 270c; 35 V parts on the 24 V input; capacitors full of leaks behind the 280c LCD. Community repair report.</ref>

Apple's exploded view lists service boards 661-1653 and 661-1717 for the 270c.<ref name="ss" /> When a 270c case bottom is replaced, the foam gaskets go into the two slots beside the white logic board support. Apple says not to fit those gaskets to any other Duo, because they can short components on the other boards.<ref name="ss" />

=== Display ===
The colour panel is a Sharp LQ9D041, driven through a display cable with separate connectors for the inverter board and the display driver board. The inverter board, brightness actuator and speaker sit inside the display housing, and the speaker cable is short enough to stop the inverter board being lifted until it is unplugged.<ref name="ss" /><ref name="macdat270c" /> The LCD carries fifteen small electrolytics and the inverter one more; mitchW found the LCD parts in good order but replaced a leaking 10 µF 35 V capacitor on the inverter.<ref name="mitch" /> Apple supplied the 270c display and its cable only to CPRC and international repairers.<ref name="ss" />

== Upgrades ==
* From a 210 or 230: the 270c upgrade kit was a complete 270c without keyboard, trackball and hard drive, into which the old parts and any modem were moved.<ref name="ss" />
* To a 280c: the 280/280c kit is a 280 case bottom, logic board and CPU stiffener assembly with a Type 3 battery and a 36 W adapter. Its new display cable is for upgrading a 250 only and must not be fitted to a 270c.<ref name="ss" />
* To a 2300c: the 2300 kit's logic board takes the 270c display cable on its TFT connector, J7.<ref name="ss" />

== Common problems ==
* Leaking electrolytics in the power circuit near the adapter socket. techknight warned that a failure there can destroy the DC-DC circuit beyond repair.<ref name="tk" /> See [[PowerBook Duo Capacitor Replacement Guide]].
* Corrosion and a burnt ceramic capacitor on a 270c that died after long use as a MIDI sequencer.<ref name="mitch" />
* Display, backlight and speaker faults that Apple's charts trace to the inverter board and display cable before the display itself.<ref name="ss" />

See [[PowerBook Duo Troubleshooting]] and [[PowerBook Duo General Maintenance]].

== Documentation ==
* [[PowerBook Duo 200 Series Service Source]]
* [[Apple Memory Guide]] (PDF p. 110)

== Related pages ==
* [[PowerBook Duo 210]], [[PowerBook Duo 230]], [[PowerBook Duo 250]], [[PowerBook Duo 280]], [[PowerBook Duo 2300]]

== References ==
<references />

{{Navbox-AppleVintage|state=collapsed}}

[[Category:Apple Vintage Computers]]

PowerBook Duo 270c - Revision history

Josh: New page: Duo 270c, specs from Apple SS and SP157, board, Sharp panel, upgrades