Apple Computers

The 8-Bit Guy talks about the history of the Apple I and shows of a modern kit of the Apple I in this video:

Apple would go on to release many more lucrative products over the years, making them the electronics giant they are known for today yet it's their early years that I find most interesting, serving as their foundations. To learn more about Apple's older computers please check out the rest of this page.

Apple Enhanced IIe

Overview

Please note that unless otherwise stated all screenshots on this page were taken from an Enhanced IIe via its composite connection, converted to HDMI and then captured using an Elgato capture card. Aspect ratio has been corrected but in the conversion to HD there will be large borders.

While this section concerns the Enhanced IIe, much of it will also be applicable to the standard IIe.

The Apple Enhanced IIe is an enhanced version of the Apple IIe -which is an enhanced version of the Apple II- so in a sense it's doubly enhanced, and was released in March 1985, 2 years after the IIe. The Enhanced IIe has a 65C02 CPU (additional instructions and ran cooler compared to the standard 6502), a new character ROM (includes MouseText characters) and 2 new firmware chips (bug fixes, lowercase support in Applesoft BASIC and the Monitor). Although some software required the Enhanced IIe, there were some compatibility issues with older programs. From the outside the Enhanced IIe is distinctive because it has either an Enhanced sticker or a 65C02 sticker on the power indicator,  between the caps lock and the open-Apple key. Additionally, an Enhanced IIe identifies itself with 'Apple //e' on its start up screen as opposed to 'Apple ][' for the standard IIe.

There are 62 keys that make up the keyboard (63 including the reset button) and each key has automatic repeat (hold down a key for to activate) and the keyboard also has N-key rollover, that is, you can hold down any combination of keys and each one is detected individually. The caps lock is of the latching type and is required to be down (caps lock on) for compatibility with software designed for Apple computers that only supported upper case. The IIe, as with other II models, has no numpad as standard but it is possible to add one to connector J16 on the motherboard, located next to the main keyboard connector J17, and the IIe Platinum does feature a keyboard with a numpad. 

A downside with the IIe trying to maintain backward compatibility with the II is that text is monochrome only; text is normally white on black, or black on white using the INVERSE BASIC command. No support for coloured text was added, and this is the case for all Apple II computers. 

Trying to use a IIe, enhanced version or not, on a modern TV or monitor will likely look very bad as the machines had very poor composite signal for both NTSC and PAL machines, a video signal that was non-standard at the time, but worked with the monitors available when the computers were on sale. Most modern monitors and TVs will have a difficult time interpreting the video signal, resulting in poor quality images. There are RGB plug-in cards and 80 column cards with their own composite or other type of video connector available but if you don't have access to one an option is to use a composite to HDMI converter. In my striving to improve the composite output of the IIe I tried two SCART composite to HDMI converters and found the cheaper one did an amazing job in producing crisp, clear composite images when the IIe is in text mode, to the point it looked like RGB rather than composite because of how clear the video looked. In graphics mode the images are not too bad (some colour bleeding) and on the downside of using the adapter it forces the image to be stretched so any captures I do I then have to correct in an image/video editing program to be the correct aspect ratio. You can see the screenshots taken using the HDMI converter along with my Elgato capture card on this page.

Sound on the IIe, as with the other II models, is very limited, only capable of 1 bit tones, by rapidly switching the speaker on/off at a particular frequency and by not having a dedicated sound chip, sound generation tied up the CPU and limited what sounds could be produced. A simple bleep can be made using PRINT CHR$(7) in BASIC but to do anything else with the built-in speaker you must use PEEK, passing certain values, which may seem odd as PEEK is normally used for returning a value from memory but certain addresses cause an action to occur, such as for the speaker to toggle on/off.

For more information about creating sound on the Apple II computers please see:

https://lateblt.tripod.com/appl2snd.htm

The Apple II uses analog joysticks/paddles (a.k.a. hand controls) which plugged into a 16-pin connector on the motherboard, and that is also present on the IIe as J15, but the IIe additionally has a DE9 game port connector at the back of the computer, which was lacking on the II. The motherboard joystick 16-pin connector is in the form of what looks to be an IC holder and carries the same game port lines as the DE9 connector but with extra signals not available through the DE9 connector. This includes the ‘annunciator’ connections, which are digital outputs that can be used to control external LEDs, for e.g., and as the joystick/paddle inputs are analogue there is no reason why they can't be used with additional components to make other types of readings, such as temperature or light.

Please see the Building an Analogue Joystick section if you would like to know how to make you own analogue controller for the IIe.

Applesoft BASIC Introduction

Apple IIe users can take advantage both of Applesoft BASIC, which is built into the computer, and Integer BASIC, which can be loaded from disk. Please see the Technical and reference section on this page for links to various documentation on BASIC, as well as the Applesoft BASIC  Vs. Integer BASIC section also on this page for a summary of some of the key differences between the two versions of BASIC.

In this section we will look at some simple BASIC programs I wrote to give a little taste of what both BASIC and the IIe can do, which I wrote and tested using Applesoft BASIC.

The first program displays a number of coloured vertical bars across the screen using the low resolution graphics mode, which uses pixels that appear as rectangular blocks. In the following program the GR command is used to enter low resolution graphics mode, COLOR sets the colour to use, and VLIN draws the vertical bars, with space between each one.

5 GR

10 FOR X = 0 TO 15

20 COLOR = X

30 VLIN 0,39 AT X * 2

40 NEXT

Running this program results in 16 vertical coloured bars appearing across the screen, showing off all the colours available in low resolution graphics mode. The colours are as follows:

0 black 4 dark green 8 brown 12 green

1 magenta 5 grey 9 orange 13 yellow

2 dark blue 6 medium blue 10 grey 14 aqua

3 purple 7 light blue 11 pink 15 white

This is what the result should look like (may vary somewhat depending on your screen/capture card):

Note that as the background is black the first vertical bar is invisible but is included for consistency. While the colours match closely what they should appear as you can see with most of the vertical bars that there appear to be made up of individual lines (even though they are supposed to be 'blocks') and additionally, some of the vertical bars are slimmer. Due to the way that the IIe handles colours by having pixels on or off in succession the pixels blocks are actually made up of a different number of coloured lines. This can be seen even clearer if we switch the computer to mono video output using its internal colour switch (PAL models only):

Clearly it can be seen that some of the vertical bars are made up of less lines and there are varying number of lines depending on the colour used, with white being the most solid.

The IIe's high resolution graphics mode has smaller pixels than the low resolution graphics mode as well, of course, higher resolution, but at the cost of far less colours. The available colours are:

0 black 1 

1 green

2 purple

3 white 1

4 black 2

5 orange

6 blue

7 white 2

Although it seems like there are 8 colours to choose from in fact there are two sets of four meaning we can only use colours from 1 set for every 7 pixels and every two pixels allows for three colours (4 if you include black which is both pixels off), effectively halving the horizontal resolution from 280 to 140.

Group 1: Black 1(00) Purple (01) Green (10) White 1(11)

Group 2: Black 2(00) Blue (01) Orange (10) White 2(11)

This gives us the limitation that only pixels with odd X-coordinates can be green or orange, and only even-numbered pixels can be purple or blue.

The high resolution graphics mode test program I wrote draws a number of coloured shapes, showing how flexible HPLOT is although Applesoft BASIC has no command to easily draw curves. HGR is used to switch to high resolution graphics mode, HCOLOR changes the colour and HPLOT draws the shapes.

5 HGR

10 HCOLOR=3

20 HPLOT 10,10 TO 50,10 TO 50,50 TO 10,50 TO 10,10

30 HPLOT 100,20 TO 70,50 TO 130,50 TO 100,20

40 HCOLOR=1

50 HPLOT 11,70 TO 71,70 TO 71,90 TO 11,90 TO 11,70

60 HCOLOR=6

70 HPLOT 40,80 TO 100,80 TO 100,100 TO 40,100 TO 40,80

80 HCOLOR=5

90 HPLOT 151,70 TO 211,70 TO 211,90 TO 151,90 TO 151,70

100 HCOLOR=6

110 HPLOT 180,80 TO 240,80 TO 240,100 TO 180,100 TO 180,80

120 HCOLOR=7

130 HPLOT 161,10 TO 178,10 TO 189,21 TO 189,39 TO 178,50 TO 161,50 TO 150,39 TO 150,21 TO 161,10

This is the result of running the program:

In the top row we have a white square, triangle and octagon. Notice how the sides of the square appear purple and one side of the octagon is blue and the opposite side orange. In the row below we have two pairs of overlapping rectangles; green and blue on the left, and orange and blue on the right. You should be able to make out that the blue rectangle 'corrupts' where it meets the green rectangle (especially the left side of the blue rectangle), whereas there is less disruption where the blue rectangle overlaps the orange rectangle.

In summary the program lines do the following:

20 Draw white square 

30 Draw white triangle

50 Draw green rectangle (start at pixel 11 rather than 10 because green is used).

70 Draw blue rectangle overlapping green rectangle (start at pixel 40 rather than 41 because blue is used).

90 Draw orange rectangle (start at pixel 151 rather than 150 because orange is used).

110 Draw blue rectangle overlapping orange rectangle.

130 Draw white octagon using white 2.

As mentioned, the IIe handles colour by use of alternating pixels on and off in different combinations which becomes even more apparent when using the high resolution graphics mode and in turn means we have to be more careful where we place certain colours, which is why in lines 50, 70 and 90 I started the shape one pixel to the right/left of where I had wanted otherwise the shape doesn't appear.

Applesoft BASIC  Vs. Integer BASIC

A few pointers highlighting just some of the differences between two versions of BASIC - Applesoft BASIC and Integer BASIC - for the Apple II computers.

The IIe DOS 3.3 system disk automatically loads Integer basic into RAM so you can use it or Applesoft BASIC which is built into the ROM. You can use the INT command to get to Integer BASIC; you will see the > prompt. To return to Applesoft BASIC use command FP. The advantage of Integer BASIC is that it's faster than Applesoft BASIC since it handles integers only whereas Applesoft BASIC can handle floating-point numbers also, and thus is more versatile.

You can use ? as shorthand for PRINT when using Applesoft BASIC but not Integer BASIC. 

Applesoft BASIC supports keywords in any case, Integer BASIC doesn’t, which requires keywords to be entered in upper case only.

Applesoft BASIC supports both low and high resolution graphics modes whereas Integer BASIC only supports low resolution graphics mode.

More differences can be read in the Applesoft BASIC programming reference manual in appendix M page 142, see link in the Technical and reference section.

Audio Line Out Adapter

The Apple IIe, like the II, has a built-in speaker so connecting to headphones or capturing the audio for a recording poses a problem. There are adapter boards you can buy that plug into the motherboard speaker connector and provide a headphone socket while still allowing the internal speaker to work if no headphones are plugged in. An example can be found at (not a sponsored link):

https://retroconnector.com/products/apple-ii/speakerheadphone-adapter-for-apple-ii/

Even with such an adapter it's not suitable to be connected to an amp, capture card or similar, which has a line-in connection. It is quite straightforward to put together a circuit that converts the speaker signal to a line level signal and still let the internal speaker work when the line-out is not in use. This is the circuit I put together:

The circuit is designed to be placed on a small circuit board that can be placed in the bottom left corner of the machine above the loudspeaker, being sure to insulate the board if you have a metal case (I used two pieces of sticky velcro). The speaker needs to be disconnected from the J18 connector on the motherboard and plugged into a suitable connector on the adapter board, marked as 'To spk' in the schematic above. Note that pin 1 is marked as a dot on the motherboard for the connector. The adapter board then has its own connector which plugs into J18 of the motherboard, observing polarity.

There are only a few components that make up the adapter board other than the already mentioned connectors, which are a couple of resistors and capacitors, which convert the speaker signal that is DC biased to line level which is centred around zero volts. To reduce the voltage to a suitable level we use a preset variable resistor PR1, which needs to be adjusted to get about 0.5V peak-to-peak; it's a good idea to use an oscilloscope. As checking with an oscilloscope while using a game can be difficult, what with infrequent and different sounds, you can use the following BASIC program which produces a constant rumbling sound:

10 A=PEEK (49200): GOTO 10

The line out connector is a headphone socket and it needs to be the type which has a normally closed, independent switch, as to disconnect the computer's internal speaker when an audio cable is plugged in. You will need to probe the socket with a multimeter if you are unsure of the pinout of your particular headphone socket. I used a TS (mono) socket but you can use a stereo socket if you like and perhaps connect both the left and right channels together.

A GND connection is needed by the circuit and I took it from pin 1 of the RF modulator connector, J13, which was quite convenient since I placed the headphone socket to the rear of the computer. You can 3D print a holder for the headphone socket to hold it in place in an available expansion connector hole at the back of the machine.

An interesting side effect of using the adapter circuit is that the sound test LED, CR2, will light when a sound is being played (which normally only happens if the internal speaker is disconnected), unless there is nothing plugged into the headphone socket.

Building an Analogue Joystick

Analogue joysticks and paddles for the Apple II feature 150K potentiometers as contrast to typical PC joysticks at the time which used 100K, so it's possible to either adapt an existing joystick/paddle to work on the II series or make our own. When an analogue joystick/paddle for the II series is operated the resistance of the potentiometer is altered which affects a timer and it is the duration of the time value that is read by the computer, resulting in a value of 0 to 255 for each axis. Thus the pots aren't actually used as potential dividers, as with other analogue joysticks of the time or modern analogue sticks, and is not an ideal way to detect joystick/paddle position since the computer has to wait between readings for the timer to finish. 

The circuit diagram for a simple analogue joystick/paddle follows that is designed to be connected to the 9-pin game port of a IIe (the pin numbering is of the connector on the IIe):

This circuit only supports 2 axes but the II series does support 4 axes so the circuit could be adapted to use 4 axes, such as for 2 joysticks or 4 paddles.

Starting with the buttons, resistors R1 to R3 pull each input low unless a button (SW1/SW2/SW3) is pressed, in which case the input goes high. Variable resistors VR1 and VR2 can be used as the axes of a joystick or as 2 paddles. If VR1 and VR2 are 150K, which matches an original Apple II controller, then C1 and C2 aren't needed. However, the capacitors allow the use of lower value variable resistors since the capacitors are placed in parallel with the IIe's internal timing capacitors, increasing the total capacitance and in turn allowing for smaller resistance values for the pots. This circuit could also be used to adapt an existing analogue joystick or paddles intended for a different system that use variable resistors other than 150K, by adding the capacitors. To calculate the capacitance of the capacitors  use this formula:

((original_potentiometer_value * internal_timing_capacitor) / new_potentiometer_value) – internal_timing_capacitor

original_potentiometer_value = 150K

internal_timing_capacitor = 0.022 uF

E.g., new_potentiometer_value = 100K we get:

((150,000 * 0.022) / 100,000) - 0.022 = 0.011uf

The formula and example were take from the following site:

https://atariage.com/forums/topic/247814-apple-ii-joystick-game-problems/

As well as testing using a game, you can use a BASIC program to print out the axes values and button states, which for the axes gives us precise values. I wrote such a program, as seen in the image below, which outputs the current values of the 4 axes as ranging from 0 to 255, and whether each button is pressed (o=not pressed, 1=pressed).

PDL(x) is used to get an axis value, passing a value from 0 to 3 for axis 1 to 4, and returning a value from 0 to 255 in relation to the associated resistance value. The FOR loops are required as a simple means to create a short delay as it's recommended to not do multiple PDL() calls in quick succession as one reading can affect another. PEEK(-16287), PEEK(-16286) and PEEK(-16285) give the state of buttons 1 to 3 but as a value <=127 if the button is not pressed, which gets converted to 0 for button not pressed or 1 for the button pressed just by PRINTing the PEEK along with a test for >127.

The result of running the program can be found as follows:

I built a simple analogue joystick for playing Star Trek: Strategic Operations Simulator since it requires the use of a joystick even though supposedly you can use the keyboard but I couldn't get that working. For the variable resistors I used an analogue stick module but it turned out to be far from ideal as for one thing there wasn't equal resistance for the same amount of push on both axes and even though the variable resistors were marked as 10K they didn't get anywhere near that value when pressed to the extreme. I also found that pressing in one direction on the analogue stick affected the value of the other axis even though I had put in a suitable delay in my BASIC test program.

When used as a voltage divider, as would typically be the case for an analogue stick, it would likely work better but when the resistances are used for timing it's not so ideal. Additionally, I didn't have the ideal capacitor values which also made the analogue stick not function so well but enough to make Star Trek playable, even with difficulty.

Emulators

Not everyone has access to original hardware so the next best thing is to use an emulator.

Apple II emulator, AppleWin:

https://github.com/AppleWin/AppleWin

Applesoft BASIC emulator in a browser:

calormen.com/jsbasic/

Keyboard differences

The IIe and Enhanced IIe don’t have the REPT key of the II, as the keys automatically repeat when held down. 

The IIe added the open and solid (a.k.a. closed) Apple keys, which the Enhanced IIe also has, with the open Apple key having the same effect as hand control #0 button and solid Apple key the same as pressing the button on hand control #1.

Software

Software was available on tapes, which could be loaded through an attached cassette player, and on 5.25 inch disks, loaded through a disk drive along with a disk controller card connected to an expansion socket. Modern solutions involve using cassette images loaded into the computer using a mobile phone/tablet/PC via the cassette interface, and the use of floppy drive emulators. Here is a site hosting software that can be downloaded

Here is an Apple II disk server that writes directly to a disk via a phone/PC/tablet:

http://asciiexpress.net/diskserver/

When I bought my Enhanced IIe second hand I got with it a number of disks including one labelled as 'Apple Arcade', which is possibly an amateur endeavour as there is no Apple copyright message and the disk includes Mario Bros, which was never officially ported to the Apple II, and a 'cracked' version of Star Trek. Here is a copy I found on Archive.org:

https://archive.org/details/a2_cple_Mario_Bros_Pac_man_Robotron_Star_Trek

The disk includes Robotron, Pac-Man, Mario Bros., and Star Trek: Strategic Operations Simulator, which are presented as selectable in the boot menu, including the 'hello' option, which is the menu itself ('hello' is the name sometimes given to a BASIC program that automatically runs when a disk is loaded). While at the menu options scroll across the bottom of the screen to manage the menu so likely it's a common program that was used on multiple disks.

I did a video showing off me playing the games which you can see below:

We will look briefly in a bit more detail at a couple of the games available on the Apple Arcade disk, the first of which we will look at is Pac-Man, released in 1982 for the Apple II by Atarisoft. While the gameplay is familiar the sound is lacking due to the II's primitive sound capabilities and the II's colour quirks show as parts of the maze take on the colour of a nearby ghost (quite minor though, compared to other microcomputers). Oddly, Pac-Man is white as there is no yellow colour in high resolution mode and white may have been chosen to allow Pac-Man to move consistently across the screen without flickering unlike the ghosts (which is quite appropriate).

Here are some screens showing the game being played:

Technical and reference

A Touch of Applesoft BASIC:
http://www.apple2.pl/books/applesoft.pdf

About your enhanced Apple IIe: user's guide:
https://www.apple.asimov.net/documentation/hardware/machines/About%20Your%20Enhanced%20Apple%20IIe%20User%27s%20Guide.pdf

Applesoft BASIC programming reference manual:
https://www.apple.asimov.net/documentation/programming/basic/Applesoft%20BASIC%20Programming%20Reference%20Manual%20-%20Apple%20Computer.pdf

Apple II BASIC programming manual:

http://cini.classiccmp.org/pdf/Apple/Apple%20II%20Basic%20Programming%20Manual.pdf

Apple IIe owner’s guide:
https://www.apple.asimov.net/documentation/hardware/machines/Apple%20IIe%20Owner%27s%20Guide.pdf

Apple II Plus/IIe Troubleshooting & Repair Guide:

https://vintageapple.org/apple_ii/pdf/Apple_II_Plus_IIe_Troubleshooting_&_Repair_Guide_1984.pdf

Apple IIe Schematic:

https://www.apple.asimov.net/documentation/hardware/schematics/Schematic%20Diagram%20of%20the%20Apple%20IIe.pdf

Apple IIe technical reference manual

http://www.applelogic.org/files/AIIETECHREF1.pdf

Assembly lines The complete book:
https://mirrors.apple2.org.za/ftp.apple.asimov.net/documentation/programming/6502assembly/Assembly%20Lines%20Complete.pdf

Apple IIe reference manual:
http://www.applelogic.org/files/AIIEREF.pdf

Apple IIe Technical Service Manual
https://www.applefritter.com/node/6911

Index to lots of technical documents for various Apple computers:
https://www.apple.asimov.net/documentation/hardware/machines/

Inside the Apple IIe
https://fabiensanglard.net/fd_proxy/prince_of_persia/Inside%20the%20Apple%20IIe.pdf

Intro to using Applesoft BASIC:
https://www.youtube.com/watch?v=1AiUPVIPd0Y&list=PLCVBS5-oiZWB7VJg8m_ehJ0SiE2taL1fE&index=5 

PEEKS, POKES, CALLS AND PROGRAMMING NOTES for IIe:
https://mirrors.apple2.org.za/ground.icaen.uiowa.edu/Collections/1WSW/MEGA.PEEKS.AND.POKES.html

Understanding the Apple IIe:

https://dmcmillan.co.uk/blog/apple-iie-without-a-keyboard/Understanding_the_Apple_IIe.pdf

Troubleshooting

Built-in testing

The most simple way to test a IIe that boots but you want to be sure that its other functions are working is to turn the computer on and then press the solid-Apple key + Control + Reset. You will see the screen full of random coloured squares and eventually some bleeping and then hopefully the System OK message otherwise if a fault is detected you will get an error message. If there is an error message, a previously running program could have set a 'soft-switch' causing a misleading error so it's worth powering the computer off and on and then running the self test again. If you still get an error then indeed there is a problem that needs to be fixed.

No colour

If don’t get any colours on the screen make sure that SW1 (on the motherboard) is set to Colour not Mono - only PAL machines have this switch. Also, text is only ever in monochrome when using text mode so you will only get colour in graphics modes (such as when playing a game, for example).

Power

Like with all old computers it's sensible to have the power supply serviced if it hasn't been recently and if looking to buy a retro Apple computer be sure to enquire as to whether the power supply has been serviced.

Repairs

A video from Noel's Retro Lab: PAL Apple IIe repair with colour issues, also, good explanation of how PAL colour video signal is generated on the IIe:

Reset

The reset button does nothing on its own, you must press Control + Reset, which should fix a computer freeze or if you just want to start fresh without turning the computer off and on again.

Apple Macintosh LC

Overview

The Macintosh LC (Low-Cost) from Apple was available from October 1990 to March 1992 and sold for $2,499, and features a Motorola 68020 32-bit CPU running at 16MHz, 2MB system RAM (expandable to 10 MB), 512KB system ROM, 256KB VRAM (expandable to 512KB), 40MB SCSI hard drive, 1.44MB floppy SuperDrive, and 8-bit mono sound (with internal speaker). The computer weighs 4.0 kg and measures 31cm x 7.4cm x 38.2cm (WHD). 

One of the consequences of the low cost design was that even though the CPU is 32-bit, the system data bus is only 16-bit, resulting in slower memory access. There is no L2 cache and the system RAM is limited to 10MB by design rather than being a CPU limit. The result is that the LC ran slower than the 16 MHz 68020-based Macintosh II from 1987, which ran almost twice as fast.

At the back of the LC you will find the power switch, IEC 3-pin mains in socket (100-240VAC 47-63hz 50W), and the following connectors; DA-15 monitor, two mini DIN 8-pin RS-422 serial (printer/modem/network), DB-25 SCSI (hard drive/floppy drive), mini DIN 4-pin ADB (Apple Desktop Bus) (keyboard/mouse), TRS 3.5mm sound out, and TRS 3.5mm microphone. The LC has an internal 96-pin PDS (Processor-Direct Slot) supporting 020 direct slot expansion card.

The LC supports Apple Keyboard, Apple Keyboard II, Apple Extended Keyboard II, and Apple Adjustable Keyboard via the ADB port, and ADB mouse and ADB Mouse II, also through the ADB port. An Apple High-Resolution Monochrome Monitor, AppleColor High-Resolution RGB Monitor, Macintosh 12-inch RGB Display, Macintosh 12-inch Monochrome Display, Macintosh Color Display, or Apple Basic Color Monitor can be connected to the monitor port. An 8VDC omnidirectional electret microphone can be connected to the microphone port. Networking could be achieve using Apple LocalTalk via the LC's serial port or through an Ethernet expansion card using the internal PDS slot. 

Even with its hardware limitations, the Macintosh LC sold well, probably in part due to the low cost and backward compatibility with the Apple II thanks to the Apple IIe Card, selling 500,000 in the first year of release, proving popular in the education and home markets. In March 1992, the LC was followed up with the 68030-based Macintosh LC II, and support for the original LC was discontinued September 1998.

Expansions

Apple IIe Card:

Resources

User manual:

https://www.manualsdir.com/manuals/548448/apple-macintosh-lc.html

Tips

The serial port is restricted to 57.6kbps.

Troubleshooting

General

Apple Macintosh LC Specification (includes troubleshooting):

https://archive.org/details/manualzz-id-1212362/mode/1up

Monitor

Macintosh LC Monitor Restoration:

Video

If your LC was working but now you get nothing on your display (or sometimes you do) even though you hear the boot chime and there is hard drive access, it may be that the computer's PRAM battery is dead or low; it is recommended to replace the battery if it measures less than 3V. The battery is rated 3.6v, 850mAh, 1/2 "AA" and once replaced you should get video output again, fortunately it's still possible to buy new compatible batteries as of 2023. Here's a video showing how to change the battery on an LC III, which is the same for all LC versions:

On a related note, if you don't intend to use your LC for a long period then it's a good idea to take the battery out, although the computer will loose its settings, there have been cases of the PRAM battery leaking or even exploding when left in.

All content of this and related pages is copyright (c) James S. 2021-2023