GS WorldView Presents an Online Exclusive [::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::] [: Apple IIE Repair Guide :] [::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::] [: Part 1 of 5 :] [::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::] Written By: Double Density [::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::] INTRODUCTION ------------ 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 moment. 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) driver 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) logic 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) This concludes the first part in this series. 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.