From: lapoint@adm.brl.mil (Claude Lapointe)
Newsgroups: comp.sys.mac.hardware,comp.sys.mac.misc
Subject: RE:  MacPlus failure (SUMMARY)
Date: 20 Nov 92 14:52:03 GMT
Followup-To: comp.sys.mac.hardware
Organization: Ballistic Research Lab (BRL), APG, MD.

Posted this earlier, but it hasn't appeared, so here it is again.
Sorry if it's a duplicate.




Earlier I posted (abbreviated)


     MacPlus, one of the earlier 1 meg versions, display collapsed to a
     single bright vertical line in middle of screen. Other symptoms:

     1- for some time, there had been intermittent screen jitter, as if
        small groups of and individual scan lines would rapidly oscillate
        laterally a few pixels

     2- for some time, displayed objects were narrower the closer to the
        right edge of the display they appeared

     3- very shortly before failure, several repetitions of single scan
        lines flashing very bright, giving the impression of a spark

     4- powering down, waiting 15-30 minutes or so, and restarting causes
        everything to work, apparently correctly, for about 10-20 minutes
        or so, then failure

I indicated this seemed to be the oft reported video failure and asked for
suggestions and sources of supply.

A responder asked me to assist him, so here is a summary of responses
and of information from earlier posts.

Thanks to all who provided info.

--------------------------------------------------------------

Books:

Macintosh Repair and Upgrade Secrets
   Larry Pina, Hayden Books, 1990, $32.95
   ISBN 0-672-48452-8

Dead Mac Scrolls
   Larry Pina, Goldstein & Blair, 1992, $32
   ISBN 0-940235-25-0

Chilton's Guide To Macintosh Repair and Maintenance
   Gene Williams, Chilton Book Company, 1986, $13.95
   ISBN 0-8019-7639-1

book out by Sam's, called something like "How to Repair
   and Upgrade Your Mac"

Pina's books are highly acclaimed, and reputed to contain specific
instructions for repairing my problem and many others. Individual
parts are identified. Pina's 1990 book is superseded by the 1992 one.

--------------------------------------------------------------

There was agreement that my problem is indeed the typical flyback
and/or cold solder joint and/or bad capacitor problem.

It was generally thought that people with soldering experience, attention
to detail, and willingness to be careful (to avoid mechanical/thermal
damage to the board itself, electrical (including static)/thermal damage
to components, and high voltage (DANGER) damage to themselves.

My solution was to order the $55 kit from Soft Solutions. For $12 extra
they include coil L2, but state it's almost never needed - if it is,
they'll supply it later at the same cost as if ordered with the kit. I
chose the kit over just the J1 connector and C1 capacitor because I
wanted maximum assurance I wouldn't have to do a 2nd repair. I avoided
the L2 coil because it probably isn't necessary, and because (I think)
it requires an adjustment, with which I didn't want to fuss. SS provides
2nd day delivery for $6, 72 hour turnaround if they do the repair.
They provide 12 mo warranties either way, but the warranty covers
more stuff if they do the repair.

I well might have had G.E. Computer swap the board had I received that
response sooner.

From repost by Werner about Mac repairs:

> Ideally, you need a long shaft Torx driver (similar to a hex key, but
> not the same) to get to the screws in the case handle. You can GET BY
> with a long, narrow-bladed, flat screwdriver. It will fit into
> the slots in the Torx nut. Be careful not to strip it out.
>         *
>         * DO NOT use a flat screw-driver; do NOT ADVISE to use such
>         * a screw-driver; I am certain that more than 50% of people
>         * who'd try would ruin the screws!   The cheapest way I have
>         * seen a TORX-substitue screw-driver done, was buying the
>         * right-sized (15, I believe) Torx head for a drill (<$1),
>         * a little 10 cents plastic tube (used in the American toilet
>         * flushing mechanism) that is just the right size (hollow)
>         * to stick the Torx head in, and hold it securely in place),
>         * stick it into the screw and use a pair of pliers to grip
>         * the tube at the other end and (have enough leverage to)
>         * turn...]

In addition, various parties have claimed ther is a need for a special tool
to pop the case open. I opened my Mac some time ago to add memory - don't
remember what I used for screwdriver/torx (perhaps I borrowed a torx),
but I do remember I did not need a special tool to pop open the case.
Perhaps just my hand, perhaps a screwdriver.

--------------------------------------------------------------

Sources of supply/repair

   Soft Solutions                individual parts, complete kits,
   907 River Road - Suite 98     repairs with 72 hour turnaround,
   Eugene, OR 97404-3228         all Mac models
   503-461-1136
   503-461-2005 (fax)

   MicroDoc Computer Repair      C1 on the power supply board for $3
   2477 W. 29th AV
   Eugene OR 97405
   503-344-5335
   503-344-5020 (fax)

   G.E. Computer                 $58 to exchange the analog board
   2338-G Walsh Avenue
   Santa Clara CA 95051
   408-998-2334

   Micromat Computer Systems
   7050 Redwood Blvd.
   Bay #4, Novato CA 94947
   415-898-6227

--------------------------------------------------------------

Consolidation of specific responses:

Indeed this is a classic failure, usually of C1 on the power supply board.

Experienced this problem myself, fixed it, and haven't had recurrence.
On the analog board, the vertically mounted one, there is a white cardboard
protector taped on the board to protect against shock - remove it.
Observe the four wires that come from the yoke of the display tube and see
where they connect to the board. Observe whether the solder is yellowed and
nasty looking. Resolder if the connection seems bad.

It's most likely the J9 connector or the flyback transformer on the video board.

I had Soft Solutions do a full upgrade of my board before giving my mac to
my brother and was quite happy with their service.  If you have the
original packaging, shipping UPS shouldn't be a problem.

The first time I had this problem, I had the mac repairman in a little shop
in town replace the J9 connector while I watched over his shoulder.  He
charged $25 for the job and it worked for a few years.

This is a classic failure.  Documented on p. 46 of the Dead Mac Scrolls.

Replace high freq capacitor C1 ... 3.9 micro farad NP 25/35V HF
with 3.9 NP 100V HF (a heavy-duty equivalent).

Almost certainly caused by cracked solder joints on the analog board.
You can fix it yourself in an hour or so. The joints that usually fail
are the 4 pins of plug J1 (especially the top pin). Also check capacitor
C1 and coil L2. This area is on the upper right corner of the analog
board when you face the solder side of the installed board. Resoldering
these joints will cure the problem. Look for heat discoloration of the
vinyl cover taped to the analog board. Remove the jacket. The joints in
question are often under the adhesive pad holding the jacket to the
board.

I resoldered a couple of joints on my machine and fixed it for several
months.  Later, C1 failed and I put a Soft Solutions kit in it. It's
still going strong 18 months later.

When my machine developed a similar problem, I fixed my own Mac Plus
for about 35 cents by replacing a transistor on the analog board. I
probably didn't even have to replace it. There was a cold solder
joint so bad that when I cut the glue off the transistor, it
practically fell out of the board. So, the first step is to look for
cold solder joints on your analog board. Use proper safety precautions.

Pina's "The Dead Mac Scrolls" says that if you don't smell smoke, the
probable cause is a cracked solder joint on the analog board. The
cracked joint may be covered by a foam pad. Check/resolder pin 4
(top, horizontal yoke) of the J1 connector and check/resolder tunable
coil L2 (marked width).

The Soft Solutions kit doesn't really document the upgrade process.

The solution I recommend is board-level swap of the analog/power supply
board.  Component level repairs will cost you about the same, but take
tens of hours. Call G.E. Computer. I maintain about eight "toaster"
Maintoshes at my kids' school, and have used G.E.C. twice to swap power
supplies. Total satisfaction -- very reasonable price.

You have to know how to disassemble your Plus, and safely discharge the
high-voltage components. Pina's book has all the tricks for this.