Apple IIe


The Apple IIe (styled as Apple //e, or sometimes Apple ][e) is the third model in the Apple II series of personal computers produced by Apple Computer. The e in the name stands for enhanced, referring to the fact that several popular features were now built-in that were only available as upgrades and add-ons in earlier models. It also improved upon expandability and added a few new features, which, all combined, made it very attractive to first-time computer shoppers as a general-purpose machine. The Apple IIe has the distinction of being the longest-lived computer in Apple's history, having been manufactured and sold for nearly 11 years with relatively few changes.
Although Apple hoped that 1984's Apple IIc would outsell the IIe, the latter was more popular because of its slots.[8] In March 1985, the company replaced the original machine with a new revision called the Enhanced IIe. It is completely identical to the previous machine except for 4 chips changed on the motherboard (and a small "Enhanced" or "65C02" sticker placed over the keyboard power indicator). The purpose of the update was to make the Apple IIe more compatible with the Apple IIc (released the previous year) and, to a smaller degree, the Apple II Plus. This change involved a new processor, the CMOS-based 65C02 CPU, a new character ROM for the text modes, and two new ROM firmware chips. The 65C02 added more CPU instructions, the new character ROM added 32 special "MouseText" characters (which allowed the creation of a GUI-like display in text mode, similar to IBM code page 437), and the new ROM firmware fixed problems and speed issues with 80-column text, introduced the ability to use lowercase in Applesoft BASIC and Monitor, and contained some other smaller improvements (and fixes) in the latter two (including the return of the Mini-Assembler—which had vanished with the introduction of the II Plus firmware).

Although it affected compatibility with a small number of software titles (particularly those that did not follow Apple programming guidelines and rules, used illegal opcodes that were no longer available in the new CPU, or used the alternate 80-column character set that MouseText now occupied) a fair bit of newer software — mostly productivity applications and utilities — required the Enhanced chipset to run at all. An official upgrade kit, consisting of the four replacement chips and an "Enhanced" sticker badge, was made available for purchase to owners of the original Apple IIe. An alternative at the time, which some users choose as a cost-cutting measure, was to simply purchase their own 65C02 CPU and create (unlicensed and illegal) duplicates of the updated ROMs using re-rewritable EPROM chips. When Apple phased out the Enhancement kit in the early 1990s, this became the only available method for users looking to upgrade their IIe, and remains so right up until present day. An Enhanced machine identifies itself with the name "Apple //e" on its start up splash screen (as opposed to the less-specific "Apple ][").

In January 1987 came the final revision of the Apple IIe, often referred to as the Platinum IIe, due to the color change of its case to the light-grey color scheme that Apple dubbed "Platinum". Changes to this revision were mostly cosmetic to modernize the look of the machine. Besides the color change, there was a new keyboard layout with built-in numeric keypad. The keyboard was changed to match the layout of the Apple IIGS, with the reset key moved above the ESC and '1' keys, the Open and Solid Apple modifier keys replaced by Command and Option and the power LED relocated above the numeric keypad. Gone were the recessed metal ID badges (showing the Apple logo and name, with "//e" beside it) replaced with a simpler "Apple IIe" silk screened on the case lid in the Apple Garamond font. A smaller Apple logo badge remained, which was moved to the right side of the case.

Internally, a (reduced in size) Extended 80 Columns Card was factory pre-installed, making it come standard with 128 KB RAM and Double-Hi-Res graphics enabled. The motherboard has a reduced chip count by merging the two system ROM chips into one and used higher density memory chips so its 64 KB RAM could be made up of two (64 Kbx4) chips rather than eight (64 Kbx1) chips, bringing the count down to a total of 24 chips. A solder pad location on the motherboard, present since the original IIe, for (optionally) making presses of the "Shift" keys detectable in software, is now shorted by default so that the feature is always active. Next, in a move to reduce radio frequency interference when a joystick plugs into the motherboard's Game I/O socket, filtering capacitors were added. While this made no difference to the average user, it had the negative effect of lowering the available bandwidth to the socket, which is often used by specialized devices for such purposes as measuring temperature, controlling a robotic device, or even simplistic networking for data transfer to another computer. In such cases the specialized devices were rendered useless on the Platinum IIe unless the user removed the capacitors from the board.

There were no firmware changes present, and functionally the motherboard is otherwise identical to the Enhanced IIe. This final model of the Apple IIe was discontinued on November 15, 1993, officially retiring the entire Apple II family line with it.



External links

Additional information

Apple //e repair guide

[:                         Apple IIE Repair Guide                           :] 
                                Written By: 
                              Double  Density 



I bring this series to all of the Apple //E users who have experienced the 
unfair and outrageous prices that repairmen of computers (especially at 
Computerland) charge for their services, only to replace a $0.50 chip. I myself 
have been charged $75 to have a $2.50 chip replaced, not to mention it took them 
two weeks to get to my computer to replace the damn thing.  At the end of this 
series, most repairs on your computer you should be able to do on your own, and 
most for less than the cost of a movie. 

Before I get heavily into this discussion, may I make a small suggestion? Print 
this out NOW! If you don't and your computer breaks down, then what are you 
gonna do?  Yup, you are gonna pay big bucks. 

Open your computer and take a look at the motherboard. Looks confusing, eh? Not 
really. The big black things are called integrated circuits, and these are what 
break down or fail most often. The other things we will not worry about at the 

Up and down the left side of the motherboard you will see letters A-F, and along 
the bottom the numbers 1-14. This is the way Apple locates their chips on the 
board - much like a city map with grids. Here are the names, and locations, and 
the approximate costs for each of the chips on the board. Don't let the names of 
the chips scare you or anything on this chart. It is mainly for information, and 
you won't need to know anything about the chips on the board (aside from the 
fact they are broken, which will come later). 

IC #       Location        Approximate $     Description        Notes 
74LS02        B8              0.78          Quad 2-input NOR 
74S10         C5              0.78          Triple 3-input NAND 
74S109        C1              1.34          Dual JK Flip-flop 
74LS125       E1              1.12          Tri-state quad buffer 
74LS138       B5              1.22          Expandable 3/8 Encoder 
74LS154       C10             2.80          4-16 decoder/multiplexer 
74LS166       F5              1.84          8-bit serial in, 
                                            parallel out shift register 
74LS244      B1,B3            2.80          Tri-State octal line driver 
74LS245       B2              1.70          Tri-State octal bus receiver 
74LS251       C11             1.55          Tri-State 8-input multiplexer 
74LS374       D3              1.98          Tri-State octal-D flip-flop 
NE558         A12             2.00          Quad 555 timer 
MC741         A11             0.75          Operational Amplifier 
ULN2003    Analog Card        ????          7-channel input       (from Apple) 
LM3146     Analog Card        ????          Transistor Array      (from Apple) 
MC3470     Analog Card        ????          Floppy disk           (from Apple) 
                                            read amplifier 
MC3764      F6-F13           20.00          64k x 1 bit RAM 
6502B         B4             14.00          8 bit microprocessor 
KB ROM        D12             8.00          Keyboard ROM 
VID ROM       F4             12.00          Video ROM 
CD ROM        D10            20.00          Applesoft ROM 
EF ROM        D8             20.00          Monitor ROM 
HAL           D1             56.00          Programmed Array      (from Apple) 
IOU           D6             56.00          I/O unit              (from Apple) 
MMU           D4             56.00          Memory Mgmt Unit      (from Apple) 
AY3600        D14            16.00          Keyboard Decoder 

Ok, that's all of the chips on the motherboard, and a few from the Analog card, 
that is the one inside your disk drive (apple drives only). If you need to order 
one of these chips from Radio Shack or some other local electronics store, then 
you ask for the chips by the number in the left hand column. For example, if 
your paddles were not working and the cables were good, you would need to start 
with the NE558 chip, and that is what you order. More about that later, though. 
Don't worry about the big costs of the ROM chips or the CPU. Most computer 
breakdowns are of the 74LSxxxx series and you will most normally have to deal 
with those only. 

Now, before you go poking around your motherboard popping out chips and sticking 
them back in, a few tips and reminders to keep your apple running right, and how 
not to screw anything up... 

1) Never touch ANYTHING in or on your computer, including your disk drives, 
   before grounding yourself on something. Static electricity, especially in 
   the wintertime can reach as high as 10,000 volts - enough to fry any of the 
   delicate chips inside your computer. 

2) Buy a chip puller. They are cheap, and you will save your fingers from 
   getting pins from the chips stuck in them, and blood all over everything. 

3) Always note the orientation of the chip you pull out, so that you can put 
   the new chip in the same way. There is a notch in one end of the chip, or a 
   dot at one end. Either way, be sure the new chip has the notch or dot in the 
   same place as the old one. 

4) Use power strips and surge protectors. The surge protector for obvious 
   reasons, and the power strip for preventing wear and tear on the switches. 
5) Keep your coke off the keyboard. Liquids can blow every chip they touch. 
6) Take special care about static electricity when messing around with the CPU, 
   the ROM chips, the MMU and the IOU chips. These are quite sensitive to 
   static charges. 

7) Don't open your monitor. This is stupid, xrays and 30kV's are running around 
   inside and if you don't know what you are doing, you will have radiation 
   damage, or worse yet, your parent will smile when they collect life 
   insurance on you. 

8) Don't pull cards out or put cards in when the power is on. You will kill 
   either the card or the computer, I promise. 

9) Check everything outside of the computer before you start fiddling around 
   inside.  Usually cables, switches or other shit like that are the cause of 
   the problem. 

Now: I am dividing up this series into 5 parts as follows: 

                        1) Start-Up Problems 
                        2) Run Problems 
                        3) Display Problems 
                        4) Keyboard Problems 
                        5) Other I/O Problems 

And I will release them as I type them. Don't hold your breath, as I am in 
school and hardly have lots of time... 

Part I - Start-Up Problems 

This section covers all problems that occur at the time you turn the power on, 
or at start up, including no power, no boot up, no beep and no display... 

1) No power light, no beep, drive won't run: 
        Probable defect:    1) 74LS125 at E1 is bad  (replace and test) 
                            2) 74S109  at C1 is bad  (replace and test) 
                            3) 74S02   at B8 is bad  (replace and test) 

2) Power light on, no message, no beep: 
        Probable defect:    1) 74S02   at B8 is bad  (replace and test) 
                            2) 74S109  at C1 is bad  (replace and test) 

3) Power light on, message, no beep: 
        Probable defect:    1) (experts only) PAL 16R8/8323T at D1 is bad 

4) System won't boot, power light on, drive won't run, garbage on screen: 
        Probable defect:    1) Bad EF ROM at E10 (replace and test) 
                            2) Bad 6502B at C4 (replace and test) 

5) System won't boot, power light on, message on screen, drive won't boot: 
        Probable defect:    1) Clean connector pins 
                            2) Clean or replace ribbon cable 
                            3) Bad ULN2003 on analog card (replace and test) 
                            4) Bad regulator on analog card (replace card) 

6) System won't boot, everything on, drive keeps running: 
        Probable defect:    1) Reseat disk, check disk, check cable, reseat 
                               card. (coming later if this doesn't work) 

7) System won't boot, disk drive runs and then stops: 
        Probable defect:    1) Bad DOS 
                            2) Bad Disk 
                            3) Bad RAM chip on motherboard (f6-14) replace 
                                                and test 

8) System boots and then stops, no display: 
        Probable defect:    1) Video cable bad (replace and test) 
                            2) Video connector bad (replace) 
                            3) Brightness knob on monitor? 
                            4) 74LS02 at B8 bad (replace and test) 
                            5) 74LS10 at C5 bad ("""""""""""""""") 
                            6) 74LS166 at F5 bad (replace and test) 
                            7) 74LS374 at D3 bad (replace and test) 
                            8) IOU at E5 bad (replace and test) 
                            9) 2732 ROM at F4 bad (replace and test) 

If you need advance help, you can reach me at my board by chat or by mail. If you have questions or suggestions, also call my board. 

Part II - Run Problems 

1) Disk drive will not read (I/O error or disk just runs on and on) 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad Disk                              Replace Disk 
     b) Wrong DOS                             Try another disk 
     c) Disk not seated                       Reseat disk 
     d) Read head not reading                 Replace head 
     e) Cable loose or bad                    Reseat or replace cable 
     f) Bad chip on analog card               Replace Analog Card 

2) Disk drive will not write (read is OK) 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Write protected                       Remove tab 
     b) Protect switch bad                    Replace switch 
     c) Disk not formatted                    format disk 
     d) Cable bad or loose                    Check/Replace cable 
     e) Corroded connectors                   Clean connectors 
     f) Bad 74LS125                           replace (analog card) 
     g) Bad CA3146                            replace    "    " 
     h) Bad MC3470                            replace    "    " 
     i) Bad ULN2003                           replace    "    " 
     j) Bad Write head                        replace 
     k) head alignment off                    realign head 

3) Disk reads or writes occasionally 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Cable corrosion                       clean connector pins 
     b) Connector corrosion                   clean connector pins 
     c) noise interference                    good luck 
     d) disk tracking off                     realign head 

4) Occasionally keyboard locks up and computer locks up 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Program error                         debug program 
     b) no keyboard out put                   coming later 
     c) bad RAM chip                          replace and test 
     d) bad MMU chip                          replace and test 
     e) bad CPU at C4                         replace and test 

Part III - Display Problems 

1) No Display - Screen all White 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) shift register latch-up               replace 74LS166 at F5 and test 
     b) ROM data hung up                      replace 2732 character ROM (F4) 

2) No Display - No Video 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad Cable                             Replace and test 
     b) low signal                            adjust brightness 
     c) Bad monitor                           test monitor 
     d) Bad 74LS02 at E8                      replace and test 
     e) Bad 2N3906 at A14                     replace and test 
     f) Bad 2N3904 at A14                     replace and test 
     g) Bad 74LS10 at C5                      replace and test 
     h) Bad 74LS166 at F5                     replace and test 
     i) Bad 2732 ROM at F4                    replace and test 
     j) Bad 74LS374 at D3                     replace and test 
     k) Bad IOU at E5                         replace and test 
     l) Bad PAL 16R8 at D1                    replace and test 

3) No Display - Screen Black 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Brightness bad                        Adjust 
     b) Bad monitor                           test monitor 
     c) Bad IOU at E5                         replace and test 
     d) Bad 2732 ROM at F4                    replace and test 

4) No Color 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad IOU at E5                         replace and test 
     b) Capacitor C32 shorted                 replace (soldering required) 
     c) Inductor L3 Bad                       replace (soldering required) 

5) No Syncronization 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad IOU at E5                         replace and test 
     b) Bad monitor                           replace or repair 

6) Bad cursor or no cursor 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad EF ROM at E10                     replace and test 
     b) Bad 2732 ROM at F4                    replace and test 

7) Bad inverse or flash 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad 2732 ROM at F4                    replace and test 

8) No text 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad 2732 ROM at F4                    Replace and test 
     b) Bad IOU ROM at E5                     Replace and test 

9) Video - Bad color 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad HAL at D1                         Replace and test 

10) Bad Graphics (lo and Hi bad); text ok 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad IOU at E5                         Replace and test 

11) Bad Graphics (HI), low and text ok 

     Probable Defect:                         Remedy: 
     ---------------                          ------- 
     a) Bad IOU at E5                         replace and test 

Part IV - Keyboard Problems 

1) Bad key action - some keys or no keys work 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad Key                               replace key 
     b) Bad or loose cable                    check and replace cable 
     c) Bad AY3600 at E14                     replace and test 
     d) Bad 2716 ROM at E12                   replace and test 

2) Bad key action - prints wrong characters 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad 2716 ROM at E12                   replace and test 
     b) Bad AY3600 at E14                     replace and test 

3) Bad key action - unwanted repeat 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad AY3600 at E14                     replace and test 
     b) Bad capacitor C71                     replace (soldering required) 

4) Repeat key won't work 

     Probable Defect:                         Remedy: 
     ----------------                         ------- 
     a) Bad Key                               replace and test 
     b) Bad AY3600 at E14                     replace and test 
     c) Bad Capacitor C70                     replace (soldering required) 

5) Key top pops off 

     Well, just glue that fucker back on or get a new keyboard. 

Part V - Other input/output problems 

1) Speaker - volume too low 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) transistor Q5 marginal                replace (soldering required) 

2) Speaker - won't click 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) Bad speaker                           Replace speaker 
     b) speaker wires bad or loose            check or replace 
     c) Bad transistor (Q5)                   replace (soldering) 
     d) Bad IOU at E5                         replace and test 

3) Cassette - can't load data 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) Bad cable                             Replace and test 
     b) Volume not set pproperly              Retry at different volume 
     c) No signal on tape                     Replace tape 
     d) Bad LM741 at A11                      Replace and test 
     e) Bad 74LS251 at C12                    Replace and test 
     f) Bad 74LS154 at C10                    Replace and test 

4) Cassette - Can't write data 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) No signal to tape                     reconnect or replace cable 
     b) Tape bad                              replace tape 
     c) Bad IOU at E5                         replace and test 

5) Game paddle - does not work at all 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) Bad cable                             Replace 
     b) Bad 558 timer at A12                  Replace and test 
     c) Bad 74LS251 at C12                    Replace and test 
     d) Bad 74LS154 at C10                    Replace and test 

6) Game paddle button won't work 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) Button bad                            Replace button 
     b) Broken wire                           Replace wire 

7) Game Paddle - knob does not work correctly 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) Bad pot in paddle                     Replace pot 
     b) Broken wire in cable                  Replace wire 

8) Card in peripheral slot does not work 

     Probable Cause:                          Remedy: 
     ---------------                          ------- 
     a) Bad 74LS138 at B5                     replace and test 
     b) Bad 74LS154 at C10                    replace and test 
     c) Bad 74LS10 at C5                      replace and test 

Additional hints: 

Look and smell and feel the chips in your computer for things that seem to be 
bad or out of place. Feel for hot spots, smell for blown capacitors, etc etc. 
Notice anything out of the ordinary and replace it if it doesn't look, smell or 
feel right. You can search for heat-blown chips by cooling each chip one at a 
time with freon from a can and examining the results on the operation of your 
computer. I f you find a chip that allows the computer to work cold, but when it 
warms up, p hooey, replace it. If all fails, take it to Computerland. Their 
prices are unreasonable, but i f you couldn't fix it from what I typed, you can 
be sure that you are going to g et your money's worth from them as they try to 
track down the problem, and cry t he whole way. 


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