Tuesday, June 18, 2013

Macintosh LC Repair Part 4 - Final

You're all wondering how the repair went, right? (I hope at least) Lets review the process:

Remove caps
Clean board
Order new caps
Replace caps

The parts I ordered all came nicely packaged in separate, marked baggies and an invoice. The one mistake I made was ordering no pins for my D-Sub 9 connector! Its a shame, but I have already located a replacement. The good news is that my chance-purchase of the 26 pin connector fits the Apple IIe card perfectly!

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I will not build the cable in this post because I do not have any software to test it with, but be sure that I will in the near future. Anyhow, back to the board. My first repair was of the Power supply. The power supply was the first problem to arise when I powered up the computer.

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The first picture is of the clean board ready for new caps. You will note that the caps are not the same size as the original, but I only needed to match the pin distance. Most caps today are smaller than old ones if not at least in height, so diameter was not an issue. Through hole capacitors are very easy to replace as long as you have cleaned the hole of residual solder. Simply match the negative pin to that on the board and slide them in. The Negative pin is always denoted by either a stripe down the side or by a dark half circle on the SMT caps which follow below.

Immediately after closing the metal housing on the PSU, I plugged it in and tested the voltages. +5v, +12v and -3v...It should be a -5v, not -3. Also, the clicking was still present. Very disappointing. However I read that the TDK power supply happened to be "smart" in a way. It was able to notice load on the outputs so I hoped for the best and proceeded onward with the motherboard.

Clearly the motherboard would take the longest of all, but all I have on a day off is free time. I began on the cap furthest from the board's edge as would prove to be the easiest to reach. If I started on the outside, each following pin would be more difficult to solder. Because I recorded each cap's value, all I needed to do was check my list to ensure a proper replacement. One after the other, I replaced caps and the few soic-8 integrated circuits and the other misc. components. Oddly enough, the most difficult component to replace was the LM3080 because of the size. Once I tacked one pin in place, the other side wanted to rise up! Even the large PLCC type chip was easier to replace. Have a close look at the final board:

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The most valuable item I use during solder jobs is my flux. I have a small jar with a needle used to apply it. I place a dab on each contact to ensure a clean and evenly heated joint every time. It may be messy, but isopropyl (rubbing) alcohol cleans nearly anything from a board without damaging silk screens or plastic components. Never use "Goo gone" or "goof off." These both contain turpentine and will eat away nearly everything...

All that is left is two more caps; the caps on the Apple IIe card of course. Remember that one pad was damaged? This was relatively easy to fix. All that I needed to do was scrape up the silk screen on top of the trace that led from the missing pad and solder the cap on sideways. With both caps replaced I assumed that the card would function properly, but I later read that it requires a boot disk which I do not own.

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We are now at the point of closing her up. The Mac LC's simple clipping design means that nothing is secured with a screw and each component snaps in place. I wish more devices were designed this way today. LETS BOOT IT UP!

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System software 7.0
4,096 Kbits of RAM
Macintosh Name: Zombie LC (brought back to life in pursuit of BRAINS!) ;)

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Our new kitten Elsie approves. Cute name, eh?
All that is left is to play some terrible games, finish that cable and find some software so I can run 'real' games from the Apple IIe. Text adventures, HERE I COME!

Thank you for all reading. This has been a repair by Jazz.
Stay Tuned for some circuit bending, more dissassemblies and a top secret Jazz-invention!

Friday, June 14, 2013

Macintosh LC Repair Part 3

With a list like the one I made in my last post, you would think that writing up an order would be simple. Well, it certainly could not have been more time consuming! Finding the value of capacitors I needed was simple enough with Mouser's filter at my disposal, but locating a cap of the perfect pin distance and a reasonable diameter by a reputable brand...now that takes time. The caps I chose are all from either Nichikon or Panasonic as recommended on the Bad-Caps forum. Luckily, each one of them was only a few cents more than a bad brand of caps, so no loss.

All of my parts arrived today, but first allow for me to supply links to the parts that I purchased:


















You will notice that I ordered two connectors and hoods. This is what I will use to make the proprietary Apple Y-cable for connecting a floppy drive and joystick. I do not plan on supporting a floppy drive though as I will probably never get one, but I will need a joystick for games!

Anyhow, if I plan on putting these caps on the board then I have to remove the old first! My personal favorite devices of choice: one radioshack desoldering iron and chip quik solder. I have used the same desoldering iron for several years now and have only needed to replace the $1.99 tip a couple of times, it just depends on how rough you treat it.

Chip Quik solder on the other hand is a special 63/37 Tin/Lead solder which has an incredibly low melting point. This low melting point makes it ideal for removing surface mount components such as PLCC chips, SMT caps, soic chips and more; I sometimes use it on pesky through-hole parts. The solder will remain molten for nearly a minute after applying it, so the component can be plucked right off the board without damaging contacts. It also cleans nicely from the board when you need to use ordinary solder for putting chips back on your boards.

I could not have removed any of these components from the boards without these items. I started with the Power Supply which has all through-hole caps:

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The first picture is of the filthy board after removal. Several of the caps had leaked and left a thick goo behind. The second pic is after I cleaned the board and the last picture is of all of the caps. Notice that some have a crusty residue, but others do not. Even though some of them had not leaked, they are all the same age and it is in my best interest to replace all of them.

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I started removing components as you can see above and the finished removing them and then cleaned the board. This was the most corroded area on the board and I lost none of the pads! Even the LM3080 which looked irreparable may be useable after removing the corrosion.

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Last of all as the Apple IIe card. This turned out to be the most difficult because the components are much closer together and I certainly could remove the PDS connector! One cap lost a pad, so I will have to make a repair...but only one trace out of a hundred seems to be a success! The Third is a picture of everything I removed from the motherboard. Caps, IC's and even the through-hole audio jacks. I felt that I had to remove more than was afflicted to access all of the caps.

In my final part of these posts, I will populate the board with all of my new caps and the old IC's. With any luck, we will have a fully functioning Macintosh LC!

Wednesday, June 12, 2013

Macintosh LC Repair Part 2

If I plan on making this function, I will have to replace all of the corroded and leaking capacitors as well as replace any non-functioning components that were damaged in the 20 something years of storage.

Below, I have drawn up a few quick diagrams of the board layouts and recorded all top-side capacitor values. I have not recorded any bottom-side capacitors because they do not need to be replaced. My board is marked: "APPLE COMPUTER INC. AP1455-03 © 1990 630-?3?9 - "

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Apple Macintosh LC Motherboard:

C1: Electro: 10uF/16v
C2: Tantalum: 3.3uF/16v
C3: Electro:10uF/16v
C4: Electro: 47uF/16v
C5: Electro: 10uF/16v
C6: Electro: 10uF/16v
C7: Electro: 10uF/16v
C8: Electro: 100uF/6v
C9: Electro: 47uF/16v
C10: Tantalum: 3.3uF/16v
C11: Tantalum: 3.3uF/16v
C12: Tantalum: 3.3uF/16v
C13: Electro: 47uF/16v
C14: Electro: 47uF/16v
C15: Electro: 47uF/16v
C16: Tantalum: 3.3uF/16v
C17: Tantalum: 3.3uF/16v
C19: Tantalum: 3.3uF/16v
C100: Electro: 1uF/50v
C105: Electro: 10uF/16v
C108: Electro: 10uF/16v
C111: Electro: 10uF/16v
C890: Tantalum: 3.3uF/16v

And as for my Apple IIe Card:

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C1: Electro: 22uF/35v C2: Electro: 22uF/35v

TDK Power Supply:

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C5: Electro: 180uF/385v
C8: Electro: 8.2uF/50v
C51: Electro: 1000uF/10v
C52: Electro: 1000uF/10v
C53: Electro: 270uF/25v
C54: Electro: 270uF/25v
C55: Electro: 1000uF/10v
C56: Electro: 56uF/25v
C60: Electro: 47uF/25v
C64: Electro: 270uF/10v

My plan is to purchase every capacitor that I need to replace these, keeping as close to the same values to stay safe. I may also attempt to make the Apple IIe card's proprietary cable which was originally design to hook up an original Apple II floppy drive and joystick. Apparently I am able to stored games and other software for the Apple IIe card on the internal HDD, so all I need is a joystick connector. All of the appropriate pin connections are listed here:

"Joystick (9 pin) to IIe card connector

01 01
02 21
03 02
04 20
05 12
06 19
07 10
08 03
09 11

Disk drive (19 pin) to IIe card connector

01 04
02 04
03 13
04 14
05 NC
06 05
07 22
08 23
09 06
10 15
11 24
12 07
13 16
14 25
15 08
16 17
17 26
18 09
19 18"

Ignoring the Disk Drive portion, I should be able to wire a joystick very easily; given I find the appropriate 3-row, 26-pin D-sub connector for a reasonable price.

Tuesday, June 11, 2013

Macintosh LC Repair Part 1

A generation of video gaming that I missed out on was the Apple II.Text adventures especially are something that I have always found interesting but had no means to explore. Now you may wonder "The title of your post is Mac LC not Apple II, silly" and you're right but I will get to that shortly.

This past week, I was scouring good old Craigslist for my next project and came across a cheap and complete Macintosh LC. This is one of, if not the first in the line of Low-cost-color computers around the time when Jobs was booted and the company moved exclusively to high-end expensive machines. This computer was released in 1990, the year I was born so by the time I entered middle school, they had already been replaced by IBM PCs. A shame really.

Back to the point. After picking up the computer and hearing the oh so common phrase, "It worked when we packed it up", I rushed home to find that it did in fact ... not work. Which is totally fine for me! I paid very little in my opinion and was just happy to find a new project that I knew could be repaired.

Once powered on, nothing; only a quite hum and click from the power supply area. The Floppy drive does not power up and the Hard disk drive does not spin up, so it must be an issue with the power supply. Inside I found the very most exciting component that I could have hoped for: The Apple IIe card! This particular daughter card is used to emulate an Apple IIe and an array of other daughter cards that an Apple IIe owner may install. Together with the upgraded processor and extra RAM, this machine will emulate an Apple IIe better than one itself can!...Once working of course.

It turns out that after exploring the more obvious issue, the power supply only measures voltages of +0.5v, +0.7v and -0.5v when it must supply +5v, +12v and -5v. It would seem that I now know the reason why none of the drives power on. Inspecting the motherboard though .. proved to be even more disappointing. All of the SMT capacitors are leaking and have corroded many contacts and pins of surrounding components. Even if I get the power supply running at full power, the board may not work!

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The second image is of the Apple IIe card which has two caps which are also leaking. Luckily they have done less damage than the others. Each one of these will have to be replaced if I intend on having it last another 23 years. I will also have to get it working if I plan on doing a proper 'disassembly' on it.