Tragic SIMMS installation

Tragic SIMMS installation

Post by Chris Del Gran » Sun, 21 Apr 1991 04:50:48



        A friend of mine installed two 1 meg SIMMS chips into a Mac SE a few
days ago to achieve a 2.5 megabyte configuration, and apparently everything
went fine exceptuUpon startup, the monitor was filled with vertical black
stripes and the machine never made it past the 'Happy Mac' startup icon.
        He first suspected that he had accidentally clipped the wrong
resistors (R35 & R36) but upon further examination everything was in order.
The 1 meg chips were also in the proper rows/banks, etc. All wires and cables
were intact also. The mac still would not startup properly.
        He took the machine to a local Mac dealer who said it was a fried
CPU (I believe) and charged him > $400 for a replacement. Does this seem in
order? My friend says that he didn't touch any of the other components and
such, so just how sensitive are these inner components to the human presence.
Any information would be greatly appreciated...(his dad didn't appreciate the
VISA charge and would like some answers.)  Thanks!


 
 
 

Tragic SIMMS installation

Post by Kenneth K.F. L » Sun, 21 Apr 1991 12:44:28


[Stuff about upgrading an SE and the CPU ended up being fried
somehow.]

There are a lot of sensitive components in today's computers and
it wouldn't take a whole lot to fry a component via electrostatic
discharge.  You don't have to actually touch anything because the
charge stored in your body can leap through the air; all it takes
is for the charge to touch the right place and wham!  When the SE
was upgraded, did you/your friend wear a grounding wrist strap?
If you/your friend did, was the strap connected to _metal_
(painted metal don't count)?  The environment is also important
because I've opened up my SE many times (~50) without any ill
effects (and this was before I knew about ESD, so naturally, I
had no grounding wrist strap) for which I was grateful and very
lucky.

That's one possibility.  Another is improper mounting of the new
SIMMs.  When I upgraded SIMMs in my SE to 4MB (I had upgraded to
2.5MB before without any problems) I didn't set a pair of
high-profile SIMMs and I got the same result your friend did.  I
opened up the Mac again and after careful inspection, noticed the
SIMM pins weren't in contact with their holder pins.  Reseating
the suspect SIMMs fixed it.

Ken
difficult to
______________________________________________________________________________



 
 
 

Tragic SIMMS installation

Post by Rick Bri » Wed, 24 Apr 1991 06:46:30



>         A friend of mine installed two 1 meg SIMMS chips into a Mac SE a few
> days ago to achieve a 2.5 megabyte configuration, and apparently everything
> went fine exceptuUpon startup, the monitor was filled with vertical black
> stripes and the machine never made it past the 'Happy Mac' startup icon.
>         He first suspected that he had accidentally clipped the wrong
> resistors (R35 & R36) but upon further examination everything was in order.
> The 1 meg chips were also in the proper rows/banks, etc. All wires and cables
> were intact also. The mac still would not startup properly.
>         He took the machine to a local Mac dealer who said it was a fried
> CPU (I believe) and charged him > $400 for a replacement. Does this seem in
> order? My friend says that he didn't touch any of the other components and
> such, so just how sensitive are these inner components to the human presence.
> Any information would be greatly appreciated...(his dad didn't appreciate the
> VISA charge and would like some answers.)  Thanks!



Seems like I had one SE install do that to me [I've done 50 or more] and I
was the connector on the cpu board loose (I'm guessing, it may have been
another connector for the diskdrive), anyway I just readjusted the connections
and it came up normal.  You didn't mention if there were any tones on startup,
or if there were any sadmac error codes.  The most common problem I ever had
was bad simm chips.  Dead out of the box.  As I write this, it seems the
simms in the wrong slots gives that stripe pattern.  In any event, the
problem it created, could have killed the cpu.  Loose connectors can cause
voltage surges that will zap that 68000 in a flash.  

Warning to anyone doing memory upgrades.  Pay the apple shop th $50 to
install the chips?  Or pay the Apple shop $400 for a new logic board?  They
like it either way.  If you aren't willing to take the risk (have no exper.,
etc.) don't open the box.

As to weather the Apple shope ripped you off?  I suppose it's possible, but
apple shops don't need to be dishonest to make a good buck, the design of
the Mac+ is enought to keep them rich.  I hear a lot of IIsi's are putting
smiling faces on them now...

 
 
 

Tragic SIMMS installation

Post by Jason Gar » Thu, 25 Apr 1991 01:36:13



[stuff deleted...]
  >         He first suspected that he had accidentally clipped the wrong
  > resistors (R35 & R36) but upon further examination everything was in order.
  > The 1 meg chips were also in the proper rows/banks, etc. All wires and cables
  > were intact also. The mac still would not startup properly.
There are atleast 4 different revisions of the logic board and some require
the higher density SIMMs closer to the CPU (in the back) and some require them
to be farther from the CPU (in the front).  Did your friend try it both ways?

  >         He took the machine to a local Mac dealer who said it was a fried
  > CPU (I believe) and charged him > $400 for a replacement. Does this seem in
  > order? My friend says that he didn't touch any of the other components and
  > such, so just how sensitive are these inner components to the human presence.
  > Any information would be greatly appreciated...(his dad didn't appreciate the
  > VISA charge and would like some answers.)  Thanks!

Actually the most common cause of the symptom you just described is a problem
with the ROMs.  This can usually be corrected by just replaceing the ROMs.
Many Apple dealer don't do this. (or maybe they don't realize that they can do
this).  A possible cheaper alternative would have been to have an FDHD ROM
upgrade installed.  This would only have cost about $100 instead of the $400.

Jason Garms

 
 
 

Tragic SIMMS installation

Post by daniel j rub » Thu, 25 Apr 1991 08:54:11


When I installed my simms, I could not get my mac to boot up correctly.
I thought that I fried a cmos chip or something, but actually I just did
not shove the simms in their sockets hard enough and all of the traces on
the simms pc board were not making good contacts with the socket.  Try to
re-install the simms with a little more force.
 
 
 

Tragic SIMMS installation

Post by Theodore John Swi » Fri, 10 May 1991 06:30:10


Quote:> A friend of mine installed two 1 meg SIMMS chips into a Mac SE a few
> days ago to achieve a 2.5 megabyte configuration, and apparently everything
> went fine exceptuUpon startup, the monitor was filled with vertical black
> stripes and the machine never made it past the 'Happy Mac' startup icon.
> ...He took the machine to a local Mac dealer who said it was a fried
> CPU (I believe) and charged him > $400 for a replacement. Does this seem in
> order? My friend says that he didn't touch any of the other components and
> such, so just how sensitive are these inner components to the human presence.

Hmmm... if it really made it as far as the "happy Mac" icon, then it's not
strictly a fried CPU: if the 68000 itself was fried, you wouldn't even get
the "bing" at start time, and it certainly woundn't have it together enough
to get the Happy Mac on the screen; it would just be an 80 watt paperweight.
From your description, it sounds like the dealer probably said "it's a fried
CPU _board_ (as opposed to the only other board, the power supply board).
Field repair of Macs is almost too simple: it's either the CPU (or logic)
board, the power supply/video board, the floppy drive, or the picture tube.
The dealer undoubtedly has no clue as to what's wrong, but $400 is the price
of pulling the logic board, popping in a replacement, and sending the sick
one back to Apple for repairs.  So as far as it goes, that seems like it's
"in order".  But it still doesn't explain what went wrong.  It's moot now,
but I would go over the instructions a few more times, maybe get some
independant confirmation, try the SIMMs in a known working configuration to
determine that they're not the problem, etc.
--
----------------------

"You bally well are informed, Jeeves!  Do you know everything?"
"I don't know, sir"    ~P.G. Wodehouse
 
 
 

1. Simm installation

I recently received four 1 meg simms from the chip merchants for my IICX.
I figured that I would leave the four original 256k simms in bank A and
install the four new 1 meg simms in bank B. When I booted the system it
would indicate only 2 megs total ram. I then reinstalled the four 1 meg
simms in bank A and the 256k simms in bank B. When I booted the system
again I got the correct configuration of 5 megs total ram. Was it really
necessary to install the 1 meg simms in bank A and the smaller 256 in
bank B or was it just an odd coincidence?

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